Graphics and Visualization

Transcription

1 Chapter 25. Graphics and Visualization Graphics tools available in FLUENT allow you to process the information contained in your CFD solution and easily view the results. The following sections explain how to use these tools to examine your solution. (Note that the procedure for saving hardcopy files of graphics displays is described in Section 3.12.) Section 25.1: Basic Graphics Generation Section 25.2: Customizing the Graphics Display Section 25.3: Controlling the Mouse Button Functions Section 25.4: Modifying the View Section 25.5: Composing a Scene Section 25.6: Animating Graphics Section 25.7: Creating Videos Section 25.8: Histogram and XY Plots Section 25.9: Turbomachinery Postprocessing 25.1 Basic Graphics Generation! In FLUENT you can generate graphics displays showing grids, contours, profiles, vectors, and pathlines. The following sections describe how to create these plots. (Generation of histogram and XY plots is discussed in Section 25.8.) If your model includes a discrete phase, you can also display the particle trajectories, as described in Section c Fluent Inc. November 28,

2 Graphics and Visualization Section : Displaying the Grid Section : Displaying Contours and Profiles Section : Displaying Vectors Section : Displaying Pathlines Section : Displaying Results on a Sweep Surface Displaying the Grid During the problem setup or when you are examining your solution, you may want to look at the grid associated with certain surfaces. You can display the outline of all or part of the domain, as shown in Figure ; draw the grid lines (edges), as shown in Figure ; draw the solid surfaces (filled grids) for a 3D domain, as shown in Figure ; and/or draw the nodes on the domain surfaces, as shown in Figure See also Section for information about displaying the grid on a surface that sweeps through the domain. Steps for Generating Grid or Outline Plots You can draw the grid or outline for all or part of your domain using the Grid Display panel (Figure ). Display Grid... The basic steps for generating a grid or outline plot are as follows: 1. Choose the surfaces for which you want to display the grid or outline in the Surfaces list. If you want to select several surfaces of the same type, you can select that type in the Surface Types list instead. All of the surfaces of that type will be selected automatically in the Surfaces list (or deselected, if they are all selected already). Another shortcut is to specify a Surface Name Pattern and click Match to select surfaces with names that match the specified pattern. For example, if you specify wall*, all surfaces whose names 25-2 c Fluent Inc. November 28, 2001

3 25.1 Basic Graphics Generation Y X Z Grid Outline Figure : Outline Display Y X Z Grid Figure : Grid Edge Display c Fluent Inc. November 28,

4 Graphics and Visualization Y X Z Grid Figure : Grid Face (Filled Grid) Display Y X Z Node Display Figure : Node Display 25-4 c Fluent Inc. November 28, 2001

5 25.1 Basic Graphics Generation Figure : The Grid Display Panel begin with wall (e.g., wall-1, wall-top) will be selected automatically. If they are all selected already, they will be deselected. If you specify wall?, all surfaces whose names consist of wall followed by a single character will be selected (or deselected, if they are all selected already). To choose all outline surfaces (i.e., surfaces on the outer boundary of thedomain), click the Outline button below the Surface Types list. If all outline surfaces are already selected, this will deselect them. To choose all interior surfaces, click the Interior button. If all interior surfaces are already selected, this will deselect them. 2. Depending on what you want to draw, do one or more of the following: To draw an outline of the selected surfaces (as in Figure ), select Edges under Options and Outline under Edge Type. If c Fluent Inc. November 28,

6 Graphics and Visualization you need more detail in the outline display of a complex geometry, see the description of the Feature option, below. To draw the grid edges (as in Figure ), select Edges under Options and All under Edge Type. To generate a filled-grid display (as in Figure ), select Faces under Options. To draw the nodes on the selected surfaces (as in Figure ), select Nodes under Options. 3. Set any of the options described below. 4. Click on the Display button to draw the specified grid or outline in the active graphics window. If you choose to display filled grids, and you want a smoothly shaded display, you should turn on lighting and select a lighting interpolation method other than Flat in the Display Options panel or the Lights panel. If you display nodes, and you want to change the symbol representing the nodes, you can change the Point Symbol in the Display Options panel. See Section for details. Grid and Outline Display Options The options mentioned in the procedure above include modifying the grid colors, adding the outline of important features to an outline display, drawing partition boundaries, and shrinking the faces and/or cells in the display. Modifying the Grid Colors FLUENT allows you to control the colors that are used to render the grids for each zone type or surface. This capability can help you to understand grid plots quickly and easily. To modify the colors, open the Grid Colors panel (Figure ) by clicking on the Colors... button in the Grid Display panel. (Note that you can set colors individually for the grids displayed on each surface, using the Scene Description panel.) 25-6 c Fluent Inc. November 28, 2001

7 25.1 Basic Graphics Generation Figure : The Grid Colors Panel To change the color used to draw the grid for a particular zone type, select the zone type in the Types list and then select the new color in the Colors list. You will see the effect of your change when you next display the grid. Note that the surface type in the Types list applies to all surface grids (i.e., grids that are drawn for surfaces created using the panels opened from the Surface menu) except zone surfaces. Adding Features to an Outline Display For closed 3D geometries such as cylinders, the standard outline display often will not show enough detail to accurately depict the shape. This is because for each boundary, only those edges on the outside of the geometry (i.e., those that are used by only one face on the boundary) are drawn. In Figure , which shows the outline display for a complicated duct geometry, only the inlet and outlet are visible. You can capture additional features using the Feature option in the Grid Display panel. (See Figure ) Turn on Feature under Edge Type, andthensetthefeature Angle. With the default Feature Angle of 20, if the difference between the normal directions of two adjacent faces is c Fluent Inc. November 28,

8 Graphics and Visualization Figure : Standard Outline of Complex Duct Figure : Feature Outline of Complex Duct 25-8 c Fluent Inc. November 28, 2001

9 25.1 Basic Graphics Generation more than 20, the edge between those faces will be drawn. Decreasing the Feature Angle will result in more edge lines (i.e., more detail) being added to the outline display. The appropriate angle for your geometry will depend on its curvature and complexity. You can modify the Feature Angle until you find the value that yields the best outline display. Drawing Partition Boundaries If you have partitioned your grid for parallel processing, you can add the display of partition boundaries to the grid display by turning on the Partitions option in the Grid Display panel. Shrinking Faces and Cells in the Display If you need to distinguish individual faces or cells in the display, you may want to enlarge the space between adjacent faces or cells by increasing the Shrink Factor in the Grid Display panel. The default value of zero produces a display in which the edges of adjacent faces or cells overlap. A value of 1 creates the opposite extreme: each face or cell is represented by a point and there is considerable space between each one. A small value such as 0.01 may be large enough to allow you to distinguish one face or cell from its neighbor. Displays with different Shrink Factor values are shown in Figures and Remember that you must click on Display to see the effect of the change in Shrink Factor. c Fluent Inc. November 28,

10 Graphics and Visualization Figure : Grid Display with Shrink Factor = 0 Figure : Grid Display with Shrink Factor = c Fluent Inc. November 28, 2001

11 25.1 Basic Graphics Generation Displaying Contours and Profiles FLUENT allows you to plot contour lines or profiles superimposed on the physical domain. Contour lines are lines of constant magnitude for a selected variable (isotherms, isobars, etc.). A profile plot draws these contours projected off the surface along a reference vector by an amount proportional to the value of the plotted variable at each point on the surface. Sample plots are shown in Figures and See also Section for information about displaying contours or profiles on a surface that sweeps through the domain. 6.60e e e e e e e e e e e-02 Natural Convection in a Power Bus Configuration Contours of Static Pressure (pascal) Figure : Contours of Static Pressure Steps for Generating Contour and Profile Plots You can plot contours or profiles using the Contours panel (Figure ). Display Contours... The basic steps for generating a contour or profile plot are as follows: c Fluent Inc. November 28,

12 Graphics and Visualization 1.45e e e e e e e e e e e-02 Natural Convection in a Power Bus Configuration Profiles of Y-Velocity (m/s) Figure : Profile Plot of y Velocity 1. Select the variable or function to be contoured or profiled in the Contours Of drop-down list. First select the desired category in the upper list; you may then select a related quantity in the lower list. (See Chapter 27 for an explanation of the variables in the list.) 2. Choose the surface or surfaces on which to draw the contours or profiles in the Surfaces list. For 2D cases, if no surface is selected, contouring or profiling is done on the entire domain. For 3D cases, you must always select at least one surface. If you want to select several surfaces of the same type, you can select that type in the Surface Types list instead. All of the surfaces of that type will be selected automatically in the Surfaces list (or deselected, if they are all selected already). Another shortcut is to specify a Surface Name Pattern and click Match to select surfaces with names that match the specified pattern. For example, if you specify wall*, all surfaces whose names begin with wall (e.g., wall-1, wall-top) will be selected automatically. If they are all selected already, they will be deselected. If c Fluent Inc. November 28, 2001

13 25.1 Basic Graphics Generation Figure : The Contours Panel you specify wall?, all surfaces whose names consist of wall followed by a single character will be selected (or deselected, if they are all selected already). 3. Specify the number of contours or profiles in the Levels field. The maximum number of levels allowed is If you are generating a profile plot, turn on the Draw Profiles option. In the resulting Profile Options panel (Figure ) you will define the profiles as described below: (a) Set the zero height reference value for the profile (Reference Value) and the length scale factor for projection (Scale Factor). AnypointontheprofilewithavalueequaltotheReference c Fluent Inc. November 28,

14 Graphics and Visualization Figure : The Profile Options Panel Value will be plotted exactly on the defining surface. Values greater than the Reference Value will be projected ahead of the surface (in the direction of Projection Dir.) andscaledby Scale Factor), and values less than the Reference Value will be projected behind the surface and scaled. These parameters can be used to create fuller profiles when you need to display the variation in a variable which is small compared to the absolute value of the variable. Consider, for example, the display of temperature profiles when the temperature range in the domain is from 300 K to 310 K. The 10 K range in the temperature will be hard to detect when profiles are drawn using the default scaling (which will be based on the absolute magnitude of 310 K). To create a fuller profile, you can set the Reference Value to 300 and the profile Scaling Factor to 5 (for example) to magnify the display of the remaining 10 K range. In subsequent display of the profiles, the reference value of 300 will be effectively subtracted from the data before display so that the temperatures of 300 K will not be offset from the baselines. The profiles will then reflect only the variation of temperature from 300 K. (b) Set the direction in which profiles are projected (Projection c Fluent Inc. November 28, 2001

15 25.1 Basic Graphics Generation Dir.). In 2D, for example, a contour plot of pressure on the entire domain can be projected in the z direction to form a carpet plot, or a contour plot of y velocity on a sequence of y-coordinate slice lines can be projected in the y direction to form a series of velocity profiles (as shown in Figure ). (c) Click Apply and close the Profile Options panel. 5. Set any of the options described below. 6. Click on the Display button to draw the specified contours or profiles in the active graphics window. The resulting display will include the specified number of contours or profiles of the selected variable, with the magnitude on each one determined by equally incrementing between the values shown in the Min and Max fields. Contour and Profile Plot Options The options mentioned in the procedure above include drawing colorfilled contours/profiles (instead of the default line contours/profiles), specifying a range of values to be contoured or profiled, including portions of the grid in the contour or profile display, choosing node or cell values for display, and storing the contour or profile plot settings. Drawing Filled Contours or Profiles Color-filled contour or profile plots show a contour or profile display containing a continuous color display (see Figure ), instead of just drawing lines representing specific values. (Note that a color-filled profile display is often referred to as a carpet plot.) To generate a filled contour or profile plot, turn on the Filled option in the Contours panel during step 5 above. To display smoothly shaded filled contours, you must turn on lighting and select a lighting interpolation method other than Flat in the Display Options panel or the Lights panel. Note that you will not get smooth shading of filled contours if the Clip to Range (see below) option is turned on. Smooth shading of filled profiles is not available. c Fluent Inc. November 28,

16 Graphics and Visualization 1.38e e e e e e e e e e e+04 Z Y X Contours of Static Pressure (pascal) Fluent Inc. Thu Aug Figure : Filled Contours of Static Pressure Specifying the Range of Magnitudes Displayed By default, the minimum and maximum values contoured or profiled are set based on the range of values in the entire domain. This means that the color scale will start at the smallest value in the domain (shown in the Min field) and end at the largest value (shown in the Max field). If you are plotting contours or profiles on a subset of the domain (i.e., on a surface), your plot may cover only the midrange of the color scale. For example, if blue corresponds to 0 and red corresponds to 10, and the values on your surface range only from 4 to 6, your plot will contain mostly green contours or profiles, since green is the color at the middle of the default color scale. If you want to focus in on a smaller range of values, so that blue corresponds to 4 and red to 6, you can manually reset the range to be displayed. (You can also use the minimum and maximum values on the selected surfaces rather than in the entire domain to determine the range, as described below.) Another reason to manually set the range is if you are interested only in certain values. For example, if you want c Fluent Inc. November 28, 2001

17 25.1 Basic Graphics Generation to determine the region where pressure exceeds a certain value, you can increase the minimum value for display so that the lower pressure values are not displayed. To manually set the contour/profile range, turn off the Auto Range option in the Contours panel. The Min and Max fields will become editable, and you can enter the new range of values to be displayed. To show the default range at any time, click on the Compute button and the Min and Max fields will be updated. If you are drawing filled contours or profiles (as described above) you can control whether or not values outside the prescribed Min/Max range are displayed. To leave areas in which the value is outside the specified range empty (i.e., draw no contours or profiles), turn on the Clip to Range option. This is the default setting. If you turn Clip to Range off, values below the Min value will be colored with the lowest color on the color scale, and values above the Max value will be colored with the highest color on the color scale. Figures and show the results of enabling/disabling the Clip to Range option. You can also choose to base the minimum and maximum values on the range of values on the selected surfaces, rather than in the entire domain. To do this, turn off the Global Range option in the Contours panel. The Min and Max values will be updated when you next click Compute or Display. Including the Grid in the Contour Plot For some problems, especially complex 3D geometries, you may want to include portions of the grid in your contour or profile plot as spatial reference points. For example, you may want to show the location of an inlet and an outlet along with the contours. This is accomplished by turning on the Draw Grid option in the Contours panel. The Grid Display panel will appear automatically when you turn on the Draw Grid option, and you can set the grid display parameters there. When you click on Display in the Contours panel, the grid display, as defined in the Grid Display panel, will be included in the contour or profile plot. c Fluent Inc. November 28,

18 Graphics and Visualization 1.30e e e e e e e e e e e+05 Z Y X Contours of Static Pressure (pascal) Fluent Inc. Thu Aug Figure : Filled Contours with Clip to Range On 1.30e e e e e e e e e e e+05 Z Y X Contours of Static Pressure (pascal) Fluent Inc. Thu Aug Figure : Filled Contours with Clip to Range Off c Fluent Inc. November 28, 2001

19 25.1 Basic Graphics Generation Choosing Node or Cell Values In FLUENT you can choose to display the computed cell-center values or values that have been interpolated to the nodes. By default, the Node Values option is turned on, and the interpolated values are displayed. For line contours or profiles, node values are always used. If you are displaying filled contours or profiles and you prefer to display the cell values, turn the Node Values option off. Filled contours/profiles of node values will show a smooth gradation of color, while filled contours/profiles of cell values may show sharp changes in color from one cell to the next. If you are plotting contours to show the effect of a porous medium or fan, to depict a shock wave, or to show any other discontinuities or jumps in the plotted variable, you should use cell values; if you use node values in such cases, the discontinuity will be smeared by the node averaging for graphics and will not be shown clearly in the plot. Storing Contour Plot Settings! For frequently used combinations of contour variables and options, you can store the information needed to generate the contour plot by specifying a Setup number and setting up the desired information in the Contours panel. When you click on the Display button, the settings for Options, Contours Of, Min, Max, andsurfaces will be saved. You can then change the Setup number to an unused value (i.e., an ID for which no information has been saved) and generate a different contour plot. To generate a plot using the saved setup information, change the Setup number back to the value for which you saved contour information and click Display. You can save up to 10 different setups. Note that the number of contour Levels, the surfaces selected for display in the Grid Display panel (when the Draw Grid option is activated), and the settings for profiles in the Profile Options panel (when the Draw Profiles option is activated) will not besavedinthesetup, nor will the Setups be saved in the case file. c Fluent Inc. November 28,

20 Graphics and Visualization Displaying Vectors You can draw vectors in the entire domain, or on selected surfaces. By default, one vector is drawn at the center of each cell (or at the center of each facet of a data surface), with the length and color of the arrows representing the velocity magnitude (Figure ). The spacing, size, and coloring of the arrows can be modified, along with several other vector plot settings. Velocity vectors are the default, but you can also plot vector quantities other than velocity. Note that cell-center values are always used for vector plots; you cannot plot node-averaged values. See also Section for information about displaying vectors on a surface that sweeps through the domain. 1.45e e e e e e e e e e e+00 Natural Convection in a Power Bus Configuration Velocity Vectors Colored By Velocity Magnitude (m/s) Figure : Velocity Vector Plot Steps for Generating Vector Plots You can plot vectors using the Vectors panel (Figure ). Display Vectors... The basic steps for generating a vector plot are as follows: c Fluent Inc. November 28, 2001

21 25.1 Basic Graphics Generation Figure : The Vectors Panel 1. In the Vectors Of drop-down list, select the vector quantity to be plotted. By default, only velocity and relative velocity are available, but you can create your own custom vectors as described below. 2. In the Surfaces list, choose the surface(s) on which you want to display vectors. If you want to display vectors on the entire domain, select none of the surfaces in the list. If you want to select several surfaces of the same type, you can c Fluent Inc. November 28,

22 Graphics and Visualization select that type in the Surface Types list instead. All of the surfaces of that type will be selected automatically in the Surfaces list (or deselected, if they are all selected already). Another shortcut is to specify a Surface Name Pattern and click Match to select surfaces with names that match the specified pattern. For example, if you specify wall*, all surfaces whose names begin with wall (e.g., wall-1, wall-top) will be selected automatically. If they are all selected already, they will be deselected. If you specify wall?, all surfaces whose names consist of wall followed by a single character will be selected (or deselected, if they are all selected already). 3. Set any of the options described below. 4. Click on the Display button to draw the vectors in the active graphics window. Displaying Relative Velocity Vectors If you are solving your problem using one or more moving reference frames or moving meshes, you will have the option to display either the absolute vectors or the relative vectors. If you select Velocity (the default) in the Vectors Of list, the vectors will be drawn based on the absolute, stationary reference frame. If you select Relative Velocity, the vectors will be drawn based on the reference frame of the Reference Zone in the Reference Values panel. See Section for details. (If you are modeling a single rotating reference frame, you need not specify the Reference Zone; the vectors will be drawn based on the rotating reference frame.) Vector Plot Options The options mentioned in the procedure above include scaling the vector arrows, skipping the display of some vectors, displaying vectors in the plane of the data surface, displaying fixed-length or fixed-color vectors, displaying directional components of the vectors, specifying a range of values to be displayed, coloring the vectors by a different scalar field, c Fluent Inc. November 28, 2001

23 25.1 Basic Graphics Generation including portions of the grid in the vector display, and changing the style of the arrows or the scale of the arrowheads. The most common options are set in the Vectors panel, and others are set in the Vector Options panel (Figure ), which you can open by clicking on the Vector Options... button in the Vectors panel. Figure : The Vector Options Panel Scaling the Vectors By default, vectors are scaled automatically so that the arrows overlap minimally when no vectors are skipped. (See below for instructions on thinning the vector display.) With the Auto Scale option, you can modify the Scale factor (which is set to 1 by default) to increase or decrease the vector scale from the default auto scale. The main advantage of autoscaling is that the vector display with a scale factor of 1 will always be appropriate, regardless of the size of the domain, giving you a better starting point for fine-tuning the vector scale. If you turn off the Auto Scale option, the vectors will be drawn at their actual sizes scaled by the scale factor (Scale, which is set to 1 by default). The actual size of a vector is the magnitude of the vector variable (velocity, by default) at the point where it is drawn. A vector drawn at a point where the velocity magnitude is 100 m/s is drawn 100 m long, whether the domain is 0.1 m or 1000 m. You can modify the vector scale c Fluent Inc. November 28,

24 Graphics and Visualization by changing the value of Scale in the Vectors panel until the size of the vectors (i.e., the actual size multiplied by Scale) is satisfactory. Skipping Vectors If your vector display is difficult to understand because there are too many arrows displayed, you can thin out the vectors by changing the Skip value in the Vectors panel. By default, Skip is set to 0, indicating that a vector will be drawn for each cell in the domain or for each face on the selected surface (e.g., n vectors). If you increase Skip to 1, every other vector will be displayed, yielding n/2 vectors. If you increase Skip to 2, every third vector will be displayed, yielding n/3 vectors, and so on. The order of faces on the selected surface (or cells in the domain) will determine which vectors are skipped or drawn; thus adaption and reordering will change the appearance of the vector display when a nonzero Skip value is used. Drawing Vectors in the Plane of the Surface For some problems, you may be interested in visualizing velocity (or other vector) components that are normal to the flow. These secondary flow components are usually much smaller than the components in the flow direction and are difficult to see when the flow direction components are also visible. To easily view the normal flow components, you can turn on the In Plane option in the Vector Options panel. When this option is on, FLUENT will display only the vector components in the plane of the surface selected for display. If the selected surface is a cross-section of the flow domain, you will be displaying the components normal to the flow. Figure shows velocity vectors generated using the In Plane option. (Note that these vectors have been translated outside the domain, as described in Section , so that they can be seen more easily.) Displaying Fixed-Length Vectors By default, the length of a vector is proportional to its velocity magnitude. If you want all of the vectors to be displayed with the same length, you can turn on the Fixed Length option in the Vector Options c Fluent Inc. November 28, 2001

25 25.1 Basic Graphics Generation 1.50e e e e e e e e e e e-04 Z Y X Velocity Vectors in Plane Colored By Velocity Magnitude (m/s) Figure : Velocity Vectors Generated Using the In Plane Option panel. To modify the vector length, adjust the value of the Scale factor in the Vectors panel. Displaying Vector Components All Cartesian components of the vectors are drawn by default, so that the arrow points along the resultant vector in physical space. However, sometimes one of the components, say, the x component, is relatively large. In such cases, you may want to suppressthe x component and scale up the vectors, in order to visualize the smaller y and z components. To suppress one or more of the vector components, turn off the appropriate button(s) (X, Y, orz Component) inthevector Options panel. Specifying the Range of Magnitudes Displayed By default, the minimum and maximum vectors included in the vector display are set based on the range of vector-variable (velocity, by default) magnitudes in the entire domain. If you want to focus in on a smaller range of values, you can restrict the range to be displayed. The color c Fluent Inc. November 28,

26 Graphics and Visualization scale for the vector display will change to reflect the new range of values. (You can also use the minimum and maximum values on the selected surfaces rather than on the entire domain to determine the range, or change the scalar field by which the vectors are colored from velocity magnitude to any other scalar, as described below.) To manually set the range of velocity magnitudes (or the range of whatever scalar field is selected in the Color By drop-down list), turn off the Auto Range option in the Vectors panel. The Min and Max fields will become editable, and you can enter the new range of values to be displayed. For example, if you want to display velocity vectors only in regions where the velocity magnitude exceeds 150 m/s but is less than 300 m/s, you will change the value of Min to 150 and the value of Max to 300. Similarly, if you are coloring the vectors by static pressure, you can choose to display velocity vectors only in regions where the pressure is within a specified range. To show the default range at any time, click on the Compute button and the Min and Max fields will be updated. When you restrict the range of vectors displayed, you can also control whether or not values outside the prescribed Min/Max range are displayed. To leave areas in which the value is outside the specified range empty (i.e., draw no vectors), turn on the Clip to Range option. This is the default setting. If you turn Clip to Range off, values below the Min value will be colored with the lowest color on the color scale, and values above the Max value will be colored with the highest color on the color scale. This feature is the same as the one available for displaying filled contours (see Figures and ). You can also choose to base the minimum and maximum values on the range of values on the selected surfaces, rather than the entire domain. To do this, turn off the Global Range option in the Vectors panel. The Min and Max values will be updated when you next click Compute or Display. Changing the Scalar Field Used for Coloring the Vectors If you want to color the vectors by a scalar field other than velocity magnitude (the default), you can select a different variable or function in the Color By drop-down list. Select the desired category in the upper c Fluent Inc. November 28, 2001

27 25.1 Basic Graphics Generation list, and then choose one of the related quantities from the lower list. If you choose static pressure, for example, the length of the vectors will still correspond to the velocity magnitude, but the color of the vectors will correspond to the value of pressure at each point where a vector is drawn. Displaying Vectors Using a Single Color If you want all of the vectors to be the same color, you can select the color to be used in the Color drop-down list in the Vector Options panel. If no color is selected (i.e., if you choose the empty space at the top of the drop-down list the default selection), the vector color will be determined by the Color By field specified in the Vectors panel. Singlecolor vectors are useful in displays that overlay contours and vectors. Including the Grid in the Vector Plot For some problems, especially complex 3D geometries, you may want to include portions of the grid in your vector plot as spatial reference points. For example, you may want to show the location of an inlet and an outlet along with the vectors. This is accomplished by turning on the Draw Grid option in the Vectors panel. The Grid Display panel will appear automatically when you turn on the Draw Grid option, and you can set the grid display parameters there. When you click on Display in the Vectors panel, the grid display, as defined in the Grid Display panel, will be included in the vector plot. Changing the Arrow Characteristics There are five different styles available for drawing the vector arrows. Choose cone, filled-arrow, arrow, harpoon, orheadless in the Style dropdown list in the Vectors panel. The default arrow style is harpoon. If you choose a vector arrow style that includes heads, you can control the size of the arrowhead by modifying the Scale Head value in the Vector Options panel. c Fluent Inc. November 28,

28 Graphics and Visualization Creating and Managing Custom Vectors In addition to the velocity vector quantity provided by FLUENT, you can also define your own custom vectors to be plotted. This capability is available with the Custom Vectors panel. Any custom vectors that you define will be saved in the case file the next time that you save it. You can also save your custom vectors to a separate file, so that they can be used with a different case file. Creating Custom Vectors To create your own custom vector, you will use the Custom Vectors panel (Figure ). This panel allows you to define custom vectors based on existing quantities. Any vectors that you define will be added to the Vectors Of list in the Vectors panel. To open the Custom Vectors panel, click on the Custom Vectors... button in the Vectors panel. Figure : The Custom Vectors Panel The steps for creating a custom vector are as follows:! 1. Specify the name of the custom vector in the Vector Name field. Be sure that you do not specify a name that is already used for a standard vector (e.g., velocity or relative-velocity) c Fluent Inc. November 28, 2001

29 25.1 Basic Graphics Generation 2. Select the variable or function for the x component of the vector in the X Component drop-down list. First select the desired category in the upper list; you may then select a related quantity in the lower list. (See Chapter 27 for an explanation of the variables in the list.) 3. Repeat the step above to select the variable or function for the y component (and, in 3D, the z component) of the custom vector. 4. Click on the Define button. Manipulating, Saving, and Loading Custom Vectors Once you have defined your vectors, you can manipulate them using the Vector Definitions panel (Figure ). You can display a vector definition to be sure that it is correct, delete the vector if you decide that it is incorrect and needs to be redefined, or give the vector a new name. You can also save custom vectors to a file or read them from a file. The custom vector file allows you to transfer custom vectors between case files. To open the Vector Definitions panel, click on the Manage... button in the Custom Vectors panel. The following actions can be performed in the Vector Definitions panel: To check the definition of a vector, select it in the Vectors list. Its definition will be displayed in the X Component, Y Component, and Z Component fields at the top of the panel. This display is for informational purposes only; you cannot edit it. If you want to change a vector definition, you must delete the vector and define it again in the Custom Vectors panel. To delete a vector, select it in the Vectors list and click on the Delete button.! To rename a vector, select it in the Vectors list, enter a new name in the Name field, and click on the Rename button. Be sure that you do not specify a name that is already used for a standard vector (e.g., velocity or relative-velocity). c Fluent Inc. November 28,

30 Graphics and Visualization Figure : The Vector Definitions Panel To save all the vectors in the Vectors list to a file, click on the Save... button, and specify the file name in the resulting Select File dialog box (see Section 2.1.2). To read custom vectors from a file that you saved as described above, click on the Load... button and specify the file name in the resulting Select File dialog box. (Custom vectors are valid Scheme functions, and can also be loaded with the File/Read/Scheme... menu item, as described in Section 3.15.) c Fluent Inc. November 28, 2001

31 25.1 Basic Graphics Generation Displaying Pathlines Pathlines are used to visualize the flow of massless particles in the problem domain. The particles are released from one or more surfaces that you have created with the tools in the Surface menu (see Chapter 24). A line or rake surface (see Section 24.5) is most commonly used. Figure shows a sample plot of pathlines. 3.00e e e e e e e e e e+00 Y 0.00e+00 X Z Path Lines Colored by Particle Id Fluent Inc. Tue Aug Figure : Pathline Plot Note that the display of discrete-phase particle trajectories is discussed in Section Steps for Generating Pathlines You can plot pathlines using the Path Lines panel (Figure ). Display Path Lines... The basic steps for generating pathlines are as follows: 1. Select the surface(s) from which to release the particles in the Release From Surfaces list. c Fluent Inc. November 28,

32 Graphics and Visualization Figure : The Path Lines Panel 2. Set the step size and the maximum number of steps. The Step Size sets the length interval used for computing the next position of a particle. (Note that particle positions are always computed when particles enter/leave a cell; even if you specify a very large step size, the particle positions at the entry/exit of each cell will still be computed and displayed.) The value of Steps sets the maximum number of steps a particle can advance. A particle will stop when it has traveled this number of steps or when it leaves the domain. One simple rule of thumb to follow when setting these two parameters is that if you want the particles to advance through a domain of length L, thestep Size times the number of Steps should be approximately equal to L. 3. Set any of the options described below c Fluent Inc. November 28, 2001

33 25.1 Basic Graphics Generation 4. Click on the Display button to draw the pathlines, or click on the Pulse button to animate the particle positions. The Pulse button will become the Stop! button during the animation, and you must click on Stop! to stop the pulsing. Options for Pathline Plots The options mentioned in the procedure above include the following. You can include the grid in the pathline display, control the style of the pathlines (including the twisting of ribbon-style pathlines), and color them by different scalar fields and control the color scale. You can also thin the pathline display, trace the particle positions in reverse, and draw oil-flow pathlines. If you are pulsing the pathlines, you can control the pulse mode. In addition to the regular pathline display, you can also generate an XY plot of a specified quantity along the pathline trajectories. Finally, you can choose node or cell values for display (or plotting). Including the Grid in the Pathline Display For some problems, especially complex 3D geometries, you may want to include portions of the grid in your pathline display as spatial reference points. For example, you may want to show the location of an inlet and an outlet along with the pathlines (as in Figure ). This is accomplished by turning on the Draw Grid option in the Path Lines panel. The Grid Display panel will appear automatically when you turn on the Draw Grid option, and you can set the grid display parameters there. When you click on Display in the Path Lines panel, the grid display, as defined in the Grid Display panel, will be included in the plot of pathlines. Controlling the Pathline Style Pathlines can be displayed as lines (with or without arrows), ribbons, cylinders (coarse, medium, or fine), triangles, or a set of points. You can choose line, line-arrows, point, ribbon, triangle, coarse-cylinder, mediumcylinder, or fine-cylinder in the Style drop-down list in the Path Lines panel. (Note that pulsing can be done only on point or line styles.) c Fluent Inc. November 28,

34 Graphics and Visualization Once you have selected the pathline style, click on the Style Attributes... button to set the pathline thickness and other parameters related to the selected Style: If you are using the line or line-arrows style, set the Line Width in the Path Style Attributes panel that appears when you click on the Style Attributes... button. For line-arrows you will also set the Arrow Scale, which controls the size of the arrow heads. If you are using the point style, you will set the Marker Width in the Path Style Attributes panel. The thickness of the pathline will be the thickness of the marker. If you are using the triangle or any of the cylinder styles, you will set the Width in the Path Style Attributes panel. For triangles, the specified value will be half the width of the triangle s base, and for cylinders, the value will be the cylinder s radius. If you are using the ribbon style, clicking on the Style Attributes... button will open the Ribbon Attributes panel, in which you can set the ribbon s Width. You can also specify parameters for twisting the ribbon pathlines. In the Twist By drop-down list, you can select a scalar field on which the pathline twisting is based (e.g., helicity). Select the desired category in the upper list and then select a related quantity in the lower list. Note that the twisting may not be displayed smoothly because the scalar field by which you are twisting the pathline is calculated at cell centers only (and not interpolated to a particle s position). The Twist Scale sets the amount of twist for the selected scalar field. To magnify the twist for a field with very little change, increase this factor; to display less twist for a field with dramatic changes, decrease this factor. (When you click on Compute, themin and Max fields will be updated to show the range of the Twist By scalar field.) Controlling Pathline Colors By default, the pathlines are colored by the particle ID number. That is, each particle s path will be a different color. You can choose to color the c Fluent Inc. November 28, 2001

35 25.1 Basic Graphics Generation pathlines byany of the scalar fieldsin thecolor By drop-down list. (Select the desired category in the upper list and then select a related quantity in the lower list.) If you color the pathlines by velocity magnitude, for example, each particle s path will be colored depending on the speed of the particle at each point in the path. The range of values of the selected scalar field will, by default, be the upper and lower limits of that field in the entire domain. The color scale will map to these values accordingly. If you prefer to restrict the range of the scalar field, turn off the Auto Range option (under Options) and set the Min and Max values manually beneath the Color By list. If you color the pathlines by velocity, and you limit the range to values between 30 and 60 m/s, for example, the lowest color will be used when the particle speed falls below 30 m/s and the highest color will be used when the particle speed exceeds 60 m/s. To show the default range at any time, click on the Compute button and the Min and Max fields will be updated. Thinning Pathlines If your pathline plot is difficult to understand because there are too many paths displayed, you can thin out the pathlines by changing the Skip value in the Path Lines panel. By default, Skip is set to 0, indicating that a pathline will be drawn from each face on the selected surface (e.g., n pathlines). If you increase Skip to 1, every other pathline will be displayed, yielding n/2 pathlines. If you increase Skip to 2, every third pathline will be displayed, yielding n/3, and so on. The order of faces on the selected surface will determine which pathlines are skipped or drawn; thus adaption and reordering will change the appearance of the pathline display when a non-zero Skip value is used. Reversing the Pathlines If you are interested in determining the source of a particle for which you know the final destination (e.g., a particle that leaves the domain through an exit boundary), you can reverse the pathlines and follow them from their destination back to their source. To do this, turn on the Reverse option in the Path Lines panel. All other inputs for defining c Fluent Inc. November 28,

36 Graphics and Visualization the pathlines will be exactly the same as for forward pathlines; the only difference is that the surface(s) selected in the Release From Surfaces list will be the final destination of the particles instead of their source. Plotting Oil-Flow Pathlines If you want to display oil-flow pathlines (i.e., pathlines that are constrained to lie on a particular boundary), turn on the Oil Flow option in the Path Lines panel. You will then need to select a single boundary zone in the On Zone list. The selected zone is the boundary on which the oil-flow pathlines will lie. Controlling the Pulse Mode If you are going to use the Pulse button in the Path Lines panel to animate the pathlines, you can choose one of two pulse modes for the release of particles that follow the pathlines. To release a single wave of particles, select the Single option under Pulse Mode. To release particles continuously from the initial positions, select the Continuous option. Generating an XY Plot Along Pathline Trajectories If you want to generate an XY plot along the trajectories of the pathlines you have defined, turn on the XY Plot option in the Path Lines panel. The Color By drop-down list will be replaced by Y Axis Function and X Axis Function lists. Select the variable to be plotted on the y axis in the Y Axis Function list, and specify whether you want to plot this quantity as a function of the Time elapsed along the trajectory, or the Path Length along the trajectory by selecting the appropriate item in the X Axis Function drop-down list. Specify the Step Size, numberofsteps, and other parameters as usual for a standard pathline display. Then click Plot to display the XY plot. Once you have generated an XY plot, you may want to save the plot data to a file. You can read this file into FLUENT at a later time and plot it alone using the File XY Plot panel, as described in Section , or add it to a plot of solution data, as described in Section c Fluent Inc. November 28, 2001

37 25.1 Basic Graphics Generation To save the plot data to a file,turn on the Write to File option in the Path Lines panel. The Plot button will change to the Write... button. Clicking on the Write... button will open the Select File dialog box, in which you can specify a name and save a file containing the plot data. The format of this file is described in Section Choosing Node or Cell Values In FLUENT you can determine the scalar field value at a particle location using the computed cell-center values or values that have been interpolated to the nodes. By default, the Node Values option is turned on, and the interpolated values are used. If you prefer to use the cell values, turn the Node Values option off. If you are plotting pathlines to show the effect of a porous medium or fan, to depict a shock wave, or to show any other discontinuities or jumps in the plotted variable, you should use cell values; if you use node values in such cases, the discontinuity will be smeared by the node averaging for graphics and will not be shown clearly in the plot Displaying Results on a Sweep Surface Sweep surfaces can be used when you want to examine the grid, contours, or vectors on various sections of the domain without explicitly creating the corresponding surfaces. For example, if you want to display solution results for a 3D combustion chamber, instead of creating numerous surfaces at different cross-sections of the domain, you can use a sweep surface to view the variation of the flow and temperature throughout the chamber. Steps for Generating a Plot Using a Sweep Surface You can plot grids, contours, or vectors on a sweep surface using the Sweep Surface panel (Figure ). Display Sweep Surface... The basic steps for generating a grid, contour, or vector plot using a sweep surface are as follows: c Fluent Inc. November 28,

38 Graphics and Visualization Figure : The Sweep Surface Panel 1. Under Sweep Axis, specify the (X, Y, Z) vector representing the axis along which the surface should be swept. 2. Click Compute to update the Min Value and Max Value to reflect the extents of the domain along the specified axis. 3. Under Display Type, specify the type of display you want to see: Grid, Contours, or Vectors. The first time that you select Contours or Vectors, FLUENT will open the Contours panel or the Vectors panel so you can modify the settings for the display. To make subsequent modifications to the display settings, click the Properties... button to open the Contours or Vectors panel. 4. Move the slider under Value (which indicates the value of x, y, or z) to move the sweep surface through the domain along the specified Sweep Axis. FLUENT will update the grid, contour, or vector display when you release the slider. You can also enter a c Fluent Inc. November 28, 2001

39 25.1 Basic Graphics Generation position in the Value field and press the <RETURN> key to update the display. 5. If you want to save the currently-displayed sweep surface so that you can use it for a different type of plot (e.g., a pathlines plot or an XY plot) or combine it with displays on other surfaces, click Create... to open the Create Surface panel (Figure ). Enter the Surface Name and click OK. Figure : The Create Surface Panel The surface that is created is an isosurface based on the grid coordinates; the contour or vector settings are not stored in the surface. You can also animate the sweep-surface display, as described below, rather than moving the slide bar yourself. Animating a Sweep-Surface Display The steps for animating a sweep-surface display are as follows: 1. Specify the Sweep Axis and Display Type as described above. 2. Under Animation, enter the Initial Value and Final Value for the animation. These values correspond to the minimum and maximum values along the Sweep Axis for which you want to animate the display. 3. Specify the number of Frames you want to see in the animation. 4. Click Animate. c Fluent Inc. November 28,

40 Graphics and Visualization 25.2 Customizing the Graphics Display There are a number of ways in which you can alter the graphical display once you have generated the basic elements in it (contours, grids, etc.). For example, you can overlay multiple graphics, add descriptive text or lighting to the plot, and modify the captions. These and other customizations are described in this section. Section : Overlay of Graphics Section : Opening Multiple Graphics Windows Section : Controlling Captions Section : Adding Text to the Graphics Window Section : Changing the Colormap Section : Adding Lights Section : Modifying the Rendering Options Overlay of Graphics Normally, you can see only one picture at a time in the graphics window; i.e., as one plot is generated, the previous plot is erased. Sometimes, however, you may want to see two plots overlaid. For example, you may want to plot vectors and pressure contours on the same plot (see Figure ). You can do this by turning on the Overlays option (and clicking Apply) inthescene Description panel. Display Scene... Once overlaying is enabled, subsequent graphics that you generate will be displayed on top of the existing display in the active graphics window. To generate a plot without overlays, you must turn off the Overlays option in the Scene Description panel (and remember to click Apply). When you are overlaying multiple graphics, the captions and color scale that will appear in the latest display are those that correspond to the most recently drawn graphic c Fluent Inc. November 28, 2001

41 25.2 Customizing the Graphics Display Note that when overlaying is enabled, it will apply to all graphics windows, including those that are not yet open. Turning overlays on and off does so for all graphics windows, not just for the active window. That is, if you enable overlays, open a new graphics window (as described in Section ), and then generate two or more graphics in that window, they will be overlaid. 1.27e e e e e e e e e e e-01 Velocity Vectors and Pressure Contours Fluent Inc. Tue Aug Figure : Overlay of Velocity Vectors and Pressure Contours Opening Multiple Graphics Windows During your FLUENT session, you can open up to 12 graphics windows at one time. The windows are numbered 0 through 11 and the ID number for each window will appear at the top of the frame that surrounds it. The first time you display graphics, window 0 will open automatically. To open an additional window, you can use the Display Options panel (Figure ). Display Options... Use the up arrow to increment the window ID in the Active Window field under Graphics Window and then click on the Open button. c Fluent Inc. November 28,

42 Graphics and Visualization Figure : The Display Options Panel To close an open window, increase or decrease the Active Window value to the ID of the window to be closed, and then click on the Close button that appears next to the Active Window field. (The Open button will change to the Close button if the Active Window is open.) Setting the Active Window When you have more than one graphics window open, you must identify the active window so that FLUENT will know which one to draw the plot in. There are two ways to set the active window: you can simply click any mouse button in the desired graphics window, or you can specify the ID for the desired graphics window in the Active Window field (in the Display Options panel) and click on the Set button. Regardless of the method used, this window will remain active until you set a new active window c Fluent Inc. November 28, 2001

43 25.2 Customizing the Graphics Display Controlling Captions FLUENT graphics include, by default, a caption block that consists of fields of text describing the contents of the graphic, the FLUENT product identification, an axis triad indicating the orientation of the displayed object, and a color key defining the correspondence between each color and the magnitude of the plotted variable. You can turn off the display of the captions and color scale, and/or the axis triad, if you want. You can also edit the captions directly in the graphics window. Enabling/Disabling the Captions and Color Scale You can disable the display of the captions and the color scale by turning off the Captions Visible option under Captions in the Display Options panel (Figure ). Display Options... Note that you can use the text interface to enable/disable the captions and color scale individually, and to change the size and position of the captions and color scale. display set windows text display set windows scale Editing the Captions When captions are displayed in the graphics window, you may choose to modify, delete, or add to the text that appears in the caption box. To do so, click the left mouse button in the desired location. A cursor will appear, and you can then type new text or delete the text that was originally there (using the backspace or delete key). Note that changes to existing text in the caption block will be removed when you draw new graphics in the window (unless you are overlaying multiple graphics in the same window), but text that you add on a previously empty line in the caption block will not be removed until the default caption text makes use of that line. c Fluent Inc. November 28,

44 Graphics and Visualization Adding a Title to the Caption You can define a title for your problem using the title text command: display set title! The title you define will appear on the top line of the caption, at the far left, in all subsequent plots. It will also be saved in the case file. You will need to enclose your title in quotation marks (e.g., "my title"). Enabling/Disabling the Axes You can disable the display of the axis triad by turning off the Axes Visible option under Captions in the Display Options panel (Figure ). Display Options Adding Text to the Graphics Window There are two ways to add text annotations with optional attachment lines to the graphics windows. You can either use the mouse-annotate function for one of the mouse buttons, or use the Annotate panel. Both of these methods are described in this section. Figure shows an example of a graphics display with annotated text in it. Adding Text Using the Annotate Panel Adding text to the graphics window using the Annotate panel (Figure ) allows you to control the font and color of the text. Display Annotate... The steps for adding text are as follows: 1. Under Font Specification, select the font type in the Name dropdown list, the font weight (Medium or Bold) intheweight dropdown list, the size (in points) in the Size drop-down list, the color in the Color drop-down list, and the slant (Regular or Italic) inthe Slant drop-down list c Fluent Inc. November 28, 2001

45 25.2 Customizing the Graphics Display 3.00e e e e e e e e e e+00 Y 0.00e+00 X Z Path Lines Colored by Particle Id Fluent Inc. Tue Aug Figure : Graphics Window with Text Annotation Figure : The Annotate Panel c Fluent Inc. November 28,

46 Graphics and Visualization 2. Enter the text to be added in the Annotation Text field. 3. Click on Add. You will be asked to pick the location in the graphics window where you want to place the text, using the mouse-probe button. (By default, the mouse-probe button is the right button, but you can change this using the Mouse Buttons panel, as described in Section 25.3.) If you click the mouse button once in the desired location, the text will be placed at that point. Dragging the mouse with the mouse-probe button depressed will draw an attachment line from the point where the mouse was first clicked to the point where it was released. The annotation text will be placed at the point where the mouse button was released. Adding Text Using the mouse-annotate Function To add text annotations to the graphics window using the mouse-annotate function, you must first set the function of one of the mouse buttons to be mouse-annotate in the Mouse Buttons panel. (See Section 25.3 for details about modifying the mouse button functions.) Then, click the mouse-annotate button in the desired location in the graphics window. A cursor will appear and you can type the text directly in the graphics window. Dragging the mouse with the mouse-annotate button depressed will draw an attachment line from the point where the mouse was first clicked to the point where it was released. The cursor will then appear at the point where the mouse button was released. You can use the Annotate panel to edit or delete text added using the mouse, as described below. Editing Existing Annotation Text Once you have added text to the graphics display, using either the Annotate panel or the mouse-annotate function, you may change the font characteristics of one or more text items, or delete individual text items. To modify or delete existing text, follow these steps: 1. Select the appropriate item in the Names list in the Annotate panel (Figure ). When you select a name, the associated text will c Fluent Inc. November 28, 2001

47 25.2 Customizing the Graphics Display be displayed in the Annotation Text field, and the Add button will become the Edit button. 2. Modify the Font Specification entries as desired, and click on the Edit button to modify the text, or simply click on the Delete Text button below the Names list to delete the selected text. Note that if you want to make changes to all current annotation text, you can select all of the Names instead of just one in step 1. You can move the text in the same way that you move other geometric objects in the display, using the Scene Description panel and the Transformations panel. See Section for details. Clearing Annotation Text Annotation text is associated with the active graphics window and is removed only when the annotations are explicitly cleared. To remove the annotations from the graphics window, you must click on the Clear buttonintheannotatepanel (even if you use the mouse-annotate function to add the text). If you draw new graphics in the window without clearing the annotations, they will remain visible in the new display Changing the Colormap The default colormap used by FLUENT to display graphical data (e.g., vectors) ranges from blue (minimum value) to red (maximum value). Additional predefined colormaps are available, and you can also create custom colormaps. To make any changes to the colormap, you will use the Colormap panel (Figure ). Display Colormaps...! (When you plot contours, you can temporarily modify the number of colors in the colormap by changing the number of contour levels in the Contours panel; you will only need to use the Colormap panel if you wish to change other characteristics of the colormap.) Note that if you are using a gray-scale colormap and you wish to save a gray-scale hardcopy, you should actually save a color hardcopy. When c Fluent Inc. November 28,

48 Graphics and Visualization Figure : The Colormap Panel you save a gray-scale hardcopy, FLUENT uses an internal gray scale, not the gray scale specified by the colormap. If you save a color hardcopy, the colormap you selected (i.e., your gray scale) will be used. Predefined Colormaps The following colormaps are automatically available in FLUENT: bgr: Blue represents the minimum value, green the middle, and red the maximum value. Colors in between are interpolated from blue to green, and from green to red. (This is the default colormap.) bgrb: Blue represents the minimum and maximum values, and green and red are values 1/3 and 2/3 of the maximum value, respectively. Colors in between are interpolated from blue to green, from green to red, and from red to blue. blue: The minimum value is represented by blue-black, and the maximum value by pure blue. cyan-yellow: Cyan represents the minimum value and yellow represents the maximum value c Fluent Inc. November 28, 2001

49 25.2 Customizing the Graphics Display fea: Blue represents the minimum value and red represents the maximum value. The colors in between are those used in third-party finite element analysis packages. gray: Black is used for the minimum value and white for the maximum value. green: The minimum value is represented by green-black, and the maximum value by pure green. purple-magenta: Purple represents the minimum value and magenta represents the maximum value. red: The minimum value is represented by red-black, and the maximum value by pure red. The number of colors interpolated between the colors in the scale name (e.g., between purple and magenta) will depend on the size of the colormap. Selecting a Colormap The procedure for selecting a new colormap to be used in graphics displaysisasfollows: 1. In the Colormap panel (Figure ), select the desired colormap in the Currently Defined drop-down list. This list will contain all of the colormaps predefined by FLUENT as well as any custom colormaps that you have created as described below. 2. Set any of the options described below. 3. Click Apply to update the current graphics display with the new colormap. All future displays will use the newly selected colormap and options. c Fluent Inc. November 28,

50 Graphics and Visualization Specifying the Colormap Size and Scale Once you have selected the desired colormap from the Currently Defined list, you may modify the Colormap Size. This value is the number of distinct colors in the color scale. You can also choose to use a logarithmic scale instead of a decimal scale by turning on the Log Scale option. With a log scale, the color used in the graphics display will represent the log of the value at that location in the domain. The values represented by the colors will, therefore, increase exponentially. Changing the Number Format You can change the format of the labels that define the color divisions at the left of the graphics window using the controls under the Number Format heading in the Colormap panel. To display the real value with an integral and fractional part (e.g., ), select float in the Type drop-down list. You can set the number of digits in the fractional part by changing the value of Precision. To display the real value with a mantissa and exponent (e.g., 1.0e-02), select exponential in the Type drop-down list. You can define the number of digits in the fractional part of the mantissa in the Precision field. To display the real value with either float or exponential form, depending on the size of the number and the defined Precision, choose general in the Type drop-down list. Creating a Customized Colormap You can create your own colormap by manipulating the anchor colors and the colormap size. A color scale is created by linear interpolation between the anchor colors. The color, number, and position of the anchor colors will therefore control the description of the colormap. By c Fluent Inc. November 28, 2001

51 25.2 Customizing the Graphics Display increasing the colormap size, you can increase the total number of colors and obtain a color scale that changes more gradually. The procedure you will follow is listed below: 1. In the Colormap panel, click on the Edit... button to open the Colormap Editor panel (Figure ). Figure : The Colormap Editor Panel 2. In the Colormap Editor panel, select a color scale in the Currently Defined list as your starting point. The colors in the scale will be displayed at the top of the panel. A white bar below a color is an anchor point indicating that this color is an anchor color. c Fluent Inc. November 28,

52 Graphics and Visualization! 3. If you want to add more colors to the color scale, increase the Colormap Size; to use fewer colors, decrease this value. When you use the counter arrows (or type in a value and press <RETURN>), the color scale display at the top of the panel will be updated immediately. The total number of colors must not be less than the number of anchor points. 4. To obtain the desired color scale interpolation, manipulate the anchor colors as needed:! To add an anchor point, click any mouse button on the black space directly below the desired anchor color (or click on the color itself). A white bar will appear below the color to identify it as an anchor color, and the color will automatically be selected for color-definition modification. To remove an anchor point, click on the white bar below the anchor color. The white bar will disappear and the color scale will be updated to reflect the new interpolation. To select a current anchor color in order to modify its color definition, click on the color itself at the top of the panel. To modify the color of the selected anchor color, you can change either the red/green/blue components (choose RGB, the default) or the hue/saturation/value components (choose HSV). HSV is recommended if you plan to record the graphics display on video, as it allows you to create a more subtle gradation of color and reduce the tendency of bright colors to bleed. Move the Red, Green, andblue or Hue, Sat, and Value sliders to obtain the desired color. The color scale at the top of the panel will be updated automatically to show the effect of your change. It is a good idea to note the original value of a color component before moving the slider so that you will be able to return to it if you change your mind. (See Section for instructions on using a scale slider.) c Fluent Inc. November 28, 2001

53 25.2 Customizing the Graphics Display If you make a mistake while modifying the color scale, you can start over by selecting the starting-point colormap in the Currently Defined list. 5. If you want to change the default name of the new colormap, enter the new name in the Name field. By default, custom color maps are called cmap-0, cmap-1, etc. 6. Click on OK to save the new colormap. The colormap name will now appear in the Currently Defined list in the Colormap panel and can be selected for use in the graphics display. Custom colormap definitions will be saved in the case file Adding Lights In FLUENT you can add lights with a specified color and direction to your display. These lights can enhance the appearance of the display when it contains 3D geometries. By default one light is defined. You can turn on the effect of the existing light(s) using the Display Options panel or the Lights panel, and you can add new lights using the Lights panel. Turning on Lighting Effects with the Display Options Panel To turn on the effect of lighting, you can use the Display Options panel. Display Options... IfyouturnontheLights On option under Lighting Attributes and click on the Apply button, you will see the lighting effects in the active graphics window. To turn off the lighting effects, simply turn off the Lights On option and click Apply. You can also choose the method to be used in lighting interpolation; select Flat, Gouraud, or Phong in the Lighting drop-down list. (Flat is the most basic method: there is no interpolation within the individual polygonal facets. Gouraud and Phong have smoother gradations of color because they interpolate on each facet.) c Fluent Inc. November 28,

54 Graphics and Visualization Turning on Lighting Effects with the Lights Panel You can also turn on lighting effects using the Lights panel (Figure ). Display Lights... In the Lighting Method drop-down list, choose Flat, Gouraud, orphong to enable the appropriate lighting method. (These methods are described above.) To disable lighting, select Off in the list. To see the lighting effects in the active graphics window, click on the Apply button. Defining Light Sources You can control individual lights in the Lights panel (Figure ). The Lights panel allows you to create a light and then turn it off without deleting it. In this way, you can retain lights that you have defined previously but do not wish to use at present. Display Lights... Figure : The Lights Panel c Fluent Inc. November 28, 2001

55 25.2 Customizing the Graphics Display (You can also open the Lights panel by clicking on the Lights... button in the Display Options panel.) By default, light 0 is defined to be dark gray with a direction of (1,1,1). A light source is a distant light, similar to the sun. The direction (1,1,1) means that the rays from the light will be parallel to the vector from (1,1,1) to the origin. To create an additional light (e.g., light 1), follow the steps listed below. 1. Increase Light ID to a new value (e.g., 1). 2. Turn on the Light On check button. 3. Define the light color by entering a descriptive string (e.g., lavender) in the Color field, or by moving the Red, Green, andblue sliders to obtain the desired color. The default color for all lights is dark gray. 4. Specify the light direction by doing one of the following: Enter the (X,Y,Z) Cartesian components under Direction. Click the middle mouse button in the desired location on the sphere under Active Lights. (You can also move the light along the circles on the surface of the sphere by dragging the mouse while holding down the middle button.) You can rotate the sphere by pressing the left mouse button and moving the mouse (like a trackball). Use your mouse to change the view in the graphics window so that your position in reference to the geometry is the position from which you would like a light to shine. Then click on the Use View Vector button to update the X,Y,Z fields with the appropriate values for your current position and update the graphics display with the new light direction. This method is convenient if you know where you want a light to be, but you are not sure of the exact direction vector. 5. Repeat steps 1 4 if you want to add more lights. 6. When you have defined all the lights you want, click Apply to save their definitions. c Fluent Inc. November 28,

56 Graphics and Visualization Removing a Light To remove a light, enter the ID number of the light to be removed in the Light ID field and then turn off the Light On button. When a light is turned off, its definition is retained, so you can easily add it to the display again at a later time by turning on the Light On button. For example, you may want to define three different lights to be used in different scenes. You can define each of them, and then turn on only one or two at a time, using the Light ID field and the Light On button. Once you have made all the desired modifications to the lights, remember to click on the Apply button to save the changes. Resetting the Light Definitions If you have made changes to the light definitions, but you have not yet clicked on Apply, you can reset the lights by clicking on the Reset button. All lighting characteristics will revert to the last saved state (i.e., the lighting that was in effect the last time you opened the panel or clicked on Apply) Modifying the Rendering Options Depending on the objects in your display window and what kind of graphics hardware and software you are using, you may want to modify some of the rendering parameters listed below. All are listed under the Rendering heading in the Display Options panel (Figure ). Display Options... After making a change to any of these rendering parameters, click on the Apply button to re-render the scene in the active graphics window with the new attributes. To see the effect of the new attributes on another graphics window, you must redisplay it or make it the active window (see Section ) and click Apply again. Line Width: By default, all lines drawn in the display have a thickness of 1 pixel. If you want to increase the thickness of the lines, increase the value of Line Width c Fluent Inc. November 28, 2001

57 25.2 Customizing the Graphics Display Figure : The Display Options Panel Point Symbol: By default, nodes displayed on surfaces and data points on line or rake surfaces are represented in the display by a + sign inside a circle. If you want to modify this representation (e.g., to make the nodes easier to see), you can select a different symbol in the Point Symbol drop-down list. Wireframe Animation: When you use the mouse to modify the view in the display, a wireframe representation will be displayed for all geometry during the mouse manipulation. If your computer has a graphics accelerator, you may want to disable this feature by turning off the Wireframe Animation option. Turning this option off when your computer does not have a graphics accelerator may make mouse manipulation very slow. Double Buffering: Enabling the Double Buffering option can dramatically reduce screen flicker during graphics updates. Note, however, that c Fluent Inc. November 28,

58 Graphics and Visualization if your display hardware does not support double buffering and you turn this option on, double buffering will be done in software. Software double buffering uses extra memory. Outer Face Culling: This option allows you to turn off the display of outer faces in wall zones. Outer Face Culling is useful for displaying both sides of a slit wall. By default, when you display a slit wall, one side will bleed through to the other. When you turn on the Outer Face Culling option, the display of a slit wall will show each side distinctly as you rotate the display. This option can also be useful for displaying two-sided walls (i.e., walls with fluid or solid cells on both sides). Hidden Line Removal: If you do not use hidden line removal, FLUENT will not try to determine which lines in the display are behind others; it will display all of them, and a cluttered display will result for most 3D grid displays. For most 3D problems, therefore, you should turn on the Hidden Line Removal option. You should turn this option off (for optimal performance) if you are working with a 2D problem or with geometries that do not overlap. Hidden Surface Removal: If you do not use hidden surface removal, FLU- ENT will not try to determine which surfaces in the display are behind others; it will display all of them, and a cluttered display will result for most 3D grid displays. For most 3D problems, therefore, you should turn on the Hidden Surface Removal option. You should turn this option off (for optimal performance) if you are working with a 2D problem or with geometries that do not overlap. You can choose one of the following methods for performing hidden surface removal in the Hidden Surface Method drop-down list. These options vary in speed and quality, depending on the device you are using. Hardware Z-buffer is the fastest method if your hardware supports it. The accuracy and speed of this method is hardwaredependent. Note that if this method is not available on your computer, selecting it will cause the Software Z-buffer method to be used c Fluent Inc. November 28, 2001

59 25.3 Controlling the Mouse Button Functions Painters will show fewer edge-aliasing effects than Hardware-Z-buffer. This method is often used instead of Software-Z-buffer when memory is limited. Software Z-buffer is the fastest of the accurate software methods available (especially for complex scenes), but it is memoryintensive. Z-sort only is a fast software method, but it is not as accurate as Software-Z-buffer. Graphics Device Information If you need to know which graphics driver you are using and what graphics hardware it recognizes, you can click on the Info buttoninthedisplay Options panel. The graphics device information will be printed in the text (console) window Controlling the Mouse Button Functions A convenient feature of FLUENT is that it allows you to assign a specific function to each of the mouse buttons. According to your specifications, clicking a mouse button in the graphics window will cause the appropriate action to be taken. These functions apply only to the graphics windows; they are not active when an XY plot or histogram is displayed. (See Section for information about the use of mouse buttons in these plots.) Clicking any mouse button in a graphics window will make that window the active window. Button Functions The predefined button functions available are listed below: mouse-rotate allows you to rotate the view by dragging the mouse across the screen. Dragging horizontally rotates the object about the screen s y axis; vertical mouse movement rotates the object about the screen s x axis. The function completes when the mouse button is released or the cursor leaves the graphics window. c Fluent Inc. November 28,

60 Graphics and Visualization mouse-dolly allows you to translate the view by dragging the mouse while holding down the button. The function completes when the mouse button is released or the cursor leaves the graphics window. mouse-zoom allows you to draw a zoom box, anchored at the point at which the button was pressed, by dragging the mouse with the button held down. When you release the button, if the dragging was from left to right, a magnified view of the area within the zoom box will fill the window. If the dragging was from right to left, the area of the window is shrunk to fit into the zoom box, resulting in a zoomed out view. If the mouse button is simply clicked (not dragged), the selected point becomes the center of the window. mouse-roll-zoom allows you to rotate or zoom the view, depending on the direction in which you drag the mouse. If you drag the mouse horizontally, the display will rotate about the axis normal to the screen. If you drag it vertically, the display will be magnified (if you drag it down) or shrunk (if you drag it up). The function completes when the mouse button is released or the cursor leaves the graphics window. Note that this function is similar to the function of the right mouse button in GAMBIT. mouse-probe allows you to select items from the graphics windows and request information about displayed scenes. If the probe function is turned off and you click the mouse-probe button in the graphics window, only the identity of the item on which you clicked will be printed out in the console window. If the probe function is turned on, more detailed information about a selected item will be printed out. mouse-annotate allows you to insert text into the graphics window. If the mouse button is dragged, an attachment line is drawn. When the button is released (after dragging or clicking), a cursor is displayed in the graphics window, and you can enter your text. When you are finished, press <RETURN> or move the cursor out of the graphics window. To modify or remove annotated text and attachment lines, use the Clear push button in the Annotate panel, as described in Section c Fluent Inc. November 28, 2001

61 25.3 Controlling the Mouse Button Functions Modifying the Mouse Button Functions Mouse button functions are specified in the Mouse Buttons panel (Figure ). Display Mouse Buttons... Figure : The Mouse Buttons Panel For each mouse button (Left, Middle, and Right), select the desired function in the drop-down list. The functions are listed above. If you assign the probe function to one of the buttons, select on or off as the Probe status. The new button functions take effect as soon as you click on OK. That is, you do not have to redraw the graphics window to use the new functions; the appropriate function will be executed when a mouse button is subsequently clicked in a graphics window. The default button functions are as follows: Button 2D 3D Left mouse-dolly mouse-rotate Middle mouse-zoom mouse-zoom Right mouse-probe mouse-probe c Fluent Inc. November 28,

62 Graphics and Visualization 25.4 Modifying the View FLUENT allows you to control the view of the scene that is displayed in the graphics window. You can modify the view by scaling, centering, rotating, translating, or zooming the display. You can also save a view that you have created, or restore or delete a view that you saved earlier. These operations are performed in the Views panel (Figure ) or with the mouse Scaling, Centering, Rotating, Translating, and Zooming the Display Scaling and centering the display is accomplished using the Views panel (Figure ). Display Views... Figure : The Views Panel You can rotate, translate, and zoom the graphics display using either the mouse or the Camera Parameters panel (Figure ), which is opened from the Views panel c Fluent Inc. November 28, 2001

63 25.4 Modifying the View Figure : The Camera Parameters Panel Scaling and Centering You can scale and center the current display without changing its orientation by clicking on the Auto Scale buttonintheviews panel. Rotating the Display In 3D you can rotate the display in any direction, using either the mouse or the Camera Parameters panel. In 2D you can rotate the display about the axis normal to the screen, using either the mouse or the Camera Parameters panel. To rotate a 3D display with the mouse, you will use the button with the mouse-rotate function (the left button, by default). (See Section 25.3 for information about changing the mouse functions.) Click and drag the left mouse button in the graphics window to rotate the geometry in the display. You can also click and drag the left mouse button on the (x,y,z) graphics triad in the lower left corner to rotate the display. If you press the <Shift> key when you first click the mouse button to begin the rotation, the rotation will be constrained to a single direction (e.g., you can rotate about the screen s horizontal axis without changing the position relative to the vertical axis). If you want to constrain the c Fluent Inc. November 28,

64 Graphics and Visualization rotation of a 3D display to be about the axis normal to the screen, you can also use the mouse-roll-zoom function described below for 2D cases. To rotate a 3D display using the Camera Parameters panel (Figure ) you will use the dial and the scales below it and to its left: To rotate about the horizontal axis at the center of the screen, move the slider on the scale to the left of the dial up or down (see Section for instructions on using the scale). To rotate about the vertical axis at the center of the screen, move the slider on the scale below the dial to the left or right. To rotate about the axis at the center of and perpendicular to the screen, click the left mouse button on the indicator in the dial and drag it around the dial.! Note that the position of the slider or the dial indicator does not reflect the cumulative rotation about the axis; the slider or indicator will return to its original position when you release the mouse button. To rotate a 2D display about the axis normal to the screen, you can use the dial in the Camera Parameters panel, as described above for 3D cases. If you want to rotate with the mouse instead, you can use the mouseroll-zoom function. (See Section 25.3 for information about enabling this optional function.) Click the appropriate mouse button and drag the mouse to the left for clockwise rotation, or to the right for counterclockwise rotation. Spinning the Display with the Mouse When you use the mouse for rotation, you have the option to push the display into a continuous spin. This feature can be used in conjunction with video recording, or simply for interactive viewing of the domain from different angles. To activate this option, use the auto-spin? text command: display set rendering-options auto-spin? c Fluent Inc. November 28, 2001

65 25.4 Modifying the View Then display the graphics (or, if the graphics are already displayed, you can click on the Apply buttoninthedisplay Options panel). The mouserotate button will then have two uses: To perform the standard rotation, stop dragging the mouse before you release the mouse-rotate button. To start the continuous spin, release the mouse-rotate button while you are still dragging the mouse. The display will continue to rotate on its own until you click any mouse button in the graphics window again. The speed of the rotation will depend on how fast you are dragging the mouse when you release the button. For smoother rotation, turn on the Double Buffering option in the Display Options panel (see Section ). This will reduce screen flicker during graphics updates. Translating the Display By default the left mouse button is set to mouse-dolly in 2D. (See Section 25.3 for information about changing the mouse functions.) Click and drag the left mouse button in the graphics window to translate the geometry in the display. In 3D, you can either change one of the button functions to mouse-dolly and follow the instructions above for 2D, or use the mouse-zoom button (the middle button by default). Click the middle button once on the point in the display that you want to move to the center of the screen. FLUENT will redisplay the graphic with that point in the center of the window. (Note that this method can also be used in 2D.) Zooming the Display In both 2D and 3D you will use the mouse button with the mouse-zoom function (the middle button by default) or the mouse-roll-zoom function (see Section 25.3 for information about enabling this optional function), or the Camera Parameters panel to magnify and shrink the display. c Fluent Inc. November 28,

66 Graphics and Visualization With the mouse-zoom function, click the middle mouse button and drag it from left to right (creating a zoom box ) to magnify the display. Figure displays the correct dragging of the mouse, from upper left to lower right on the display, in order to zoom. (You can also drag from lower left to upper right.) After you release the mouse button, FLUENT will redisplay the graphic, filling the graphics window with the portion of the display that previously occupied the zoom box. Click the middle mouse button and drag it from right to left to shrink the display. Figure displays the correct dragging of the mouse, from lower right to upper left on the display, in order to de-zoom. (You can also drag from upper right to lower left.) After you release the mouse button, FLUENT will redisplay the graphic, shrinking the graphical display by the ratio of sizes of the zoom box you created and the previous display. With the mouse-roll-zoom function, click the appropriate mouse button and drag the mouse down to zoom in continuously, or up to zoom out. In the Camera Parameters panel (Figure ), use the scale to the right of the dial to zoom the display. Move the slider bar up to zoom in and down to zoom out Controlling Perspective and Camera Parameters Perspective and other camera parameters are defined in the Camera Parameters panel, which you can open by clicking on the Camera... button in the Views panel (Figure ). Display Views... Perspective and Orthographic Views You may choose to display either an orthographic view or a perspective view of your graphics. To show a perspective view (the default), select Perspective in the Projection drop-down list in the Camera Parameters panel (Figure ). To turn off perspective, select Orthographic in the Projection drop-down list c Fluent Inc. November 28, 2001

67 25.4 Modifying the View click here drag direction region to be zoomed release Figure : Zooming In (Magnifying the Display) release drag direction region to be un-zoomed click here Figure : Zooming Out (Shrinking the Display) c Fluent Inc. November 28,

68 Graphics and Visualization Modifying Camera Parameters Instead of translating, rotating, and zooming the display as described in Section , you may sometimes want to modify the camera through which you are viewing the graphics display. The camera is defined by four parameters: position, target, up vector, and field, as illustrated in Figure Position is the camera s location. Target is the location of the point the camera is looking at, and up vector indicates to the camera which way is up. Field indicates the field of view (width and height) of the display. view plane up vector position target x field y field Figure : Camera Definition! To modify the camera s position, select Position in the Camera dropdown list and specify the X, Y, andz coordinates of the desired point. To modify the target location, select Target in the Camera drop-down list and specify the coordinates of the desired point. Select Up Vector to change the up direction. The up vector is the vector from (0,0,0) to the specified (X,Y,Z) point. Finally, to change the field of view, select Field in the Camera list and enter the X (horizontal) and Y (vertical) field distances. Click Apply after you change each camera parameter (Position, Target, Up Vector, andfield) c Fluent Inc. November 28, 2001

69 25.4 Modifying the View Saving and Restoring Views After you make changes to the view shown in your graphics window, you may want to save the view so that you can return to it later. Several default views are predefined for you, and can be easily restored. All saving and restoring functions are performed with the Views panel (Figure ).! Display Views... Note that settings for mirroring and periodic repeats are not saved in a view. Restoring the Default View When experimenting with different view manipulation techniques, you may accidentally lose your geometry in the display. You can easily return to the default (front) view by clicking on the Default button in the Views panel. Saving Views Once you have created a new view that you want to save for future use, enter a name for it in the Save Name field in the Views panel and click on the Save button. Your new view will be added to the list of Views, and you can restore it later as described below. If a view with the same name already exists, you will be asked in a Question dialog box if it is OK to overwrite the existing view. If you overwrite one of the default views (top, left, right, front, etc.), be sure to save it in a view file if you wish to use it in a later session. (Although all views are saved to the case file, the default views are recomputed automatically when a case file is read in. Any custom view with the same name as a default view will be overwritten at that time.) As mentioned above, all defined views will be saved in the case file when you write one. If you plan to use your views with another case file, you can write a view file containing just the views. You can read this view file into another solver session involving a different case file and restore any of the defined views, as described below. c Fluent Inc. November 28,

70 Graphics and Visualization To save a view file, click on the Write... buttonintheviews panel. In the resulting Write Views panel (Figure ), select the views you want to save in the Views To Save list and click on OK. You will then use the Select File dialog box to specify the file name and save the view file. Figure : The Write Views Panel Reading View Files If you have saved views to a view file (as described above), you can read them into your current solver session by clicking on the Read... button in the Views panel, and indicating the name of the view file in the resulting Select File dialog box. If a view that you read has the same name as a view that already exists, you will be asked in a Question dialog box if it is OK to overwrite (i.e., replace) the existing view. Restoring Views You can restore any of the predefined views, views you have saved, or views that you have read from a view file. Select the view in the Views list and click on the Restore button, or just double-click on the desired view in the Views list c Fluent Inc. November 28, 2001

71 25.4 Modifying the View Deleting Views If you decide that you no longer want to keep a particular view, you can delete it by selecting it in the Views list and clicking on the Delete button. Use this option carefully, so that you do not accidentally delete one of the predefined views Mirroring and Periodic Repeats If you model the problem domain as a subset of your geometry using symmetry or periodic boundaries, you can display results on the complete geometry by mirroring or repeating the domain. For example, only one half of the annulus shown in Figure was modeled, but the graphics are displayed on both halves. You can also define mirror planes or periodic repeats just for graphical display, even if you did not model your problem using symmetry or periodic boundaries. 4.86e e e e e e e e e e e-02 Contours of Static Pressure (pascal) Fluent Inc. Tue Aug Figure : Mirroring Across a Symmetry Boundary Display of symmetry and periodic repeats is controlled in the Views panel (Figure ). c Fluent Inc. November 28,

72 Graphics and Visualization Display Views... Figure : The Views Panel For a periodic domain, specify the number of times to repeat the modeled portion by increasing the value of Periodic Repeats. If, for example, you modeled a 90 sector of a duct and you wanted to display results on the entire duct, you would set the number of Periodic Repeats to 3. For a symmetric domain, all symmetry boundaries will be listed in the Mirror Planes list. Select one or more of these boundaries as the plane(s) about which to mirror the display. When you click on Apply in the Views panel the graphics display will immediately be updated to show the requested mirroring or periodic repeats. Periodic Repeats Just for Graphics To define graphical periodicity for a non-periodic domain, follow these steps: c Fluent Inc. November 28, 2001

73 25.4 Modifying the View 1. Click on the Define... button under Periodic Repeats in the Views panel. 2. In the resulting Graphics Periodicity panel (Figure ), specify Rotational or Translational as the Periodic Type. Figure : The Graphics Periodicity Panel 3. For translational periodicity, specify the Translation distance of the repeated domain in the X, Y, andz directions. For rotational periodicity, specify the axis about which the periodicity is defined and the Angle by which the domain is rotated to create the periodic repeat. For 3D problems, the axis of rotation is the vector passing through the specified Axis Origin and parallel to the vector from (0,0,0) to the (X,Y,Z) point specified under Axis Direction. For 2D problems, you will specify only the Axis Origin; the axis of rotation is the z-direction vector passing through the specified point. 4. Click on OK in the Graphics Periodicity panel. 5. In the Views panel, specify the number of Periodic Repeats and click Apply, as described above. You can delete the definition of any periodicity you have defined for graphics by clicking on the Reset buttoninthegraphics Periodicity panel. c Fluent Inc. November 28,

74 Graphics and Visualization Mirroring Just for Graphics To define a mirror plane for a non-symmetric domain, follow the procedure below: 1. Click on the Define Plane... button under Mirror Planes in the Views panel. 2. In the resulting Mirror Planes panel (Figure ), set the coefficients of X, Y, andz and the Distance (of the plane from the origin) in the following equation for the mirror plane: Ax + By + Cz =distance Figure : The Mirror Planes Panel 3. Click on the Add button to add the defined plane to the Mirror Planes list. When you are done creating mirror planes, click OK. The newly defined plane(s) will now appear in the Mirror Planes list in the Views panel. To include the mirroring in the display, select the plane(s) and click Apply, as described above c Fluent Inc. November 28, 2001

75 25.5 Composing a Scene If you want to delete a mirror plane that you have defined, select it in the Mirror Planes list in the Mirror Planes panel and click on the Delete button. When you click OK in this panel, the deleted plane will be removed permanently from the Mirror Planes list in the Views panel Composing a Scene Once you have displayed some geometric objects (grids, surfaces, contours, vectors, etc.) in your graphics window, you may want to move them around and change their characteristics to increase the effectiveness of the scene displayed. You can use the Scene Description panel (Figure ) and the Display Properties panel (Figure ) and Transformations panel (Figure ), which are opened from within it, to rotate, translate, and scale each object individually, as well as change the color and visibility of each object. Display Scene... Figure : The Scene Description Panel The IsoValue panel (Figure ), which is also opened from within the Scene Description panel, allows you to change the isovalue of a selected c Fluent Inc. November 28,

76 Graphics and Visualization isosurface. The Pathline Attributes panel (Figure ) lets you set some pathline attributes. The ability to make geometric objects visible and invisible is especially useful when you are creating an animation (see Section 25.6) because it allows you to add or delete objects from the scene one at a time. The ability to change the color and position of an object independently of the others in the scene is also useful for setting up animations, as is the ability to change isosurface isovalues. You will find the features in the Scene Description panel useful even when you are not generating animations because they allow you to manage your graphics window efficiently. (Note that you cannot use the Scene Description panel to control XY plot and histogram displays.) Note that the Time Step... option is not available in FLUENT. (It is available only for the Fluent Inc. postprocessing program, FLUENT/Post. See the FLUENT/Post User s Guide for details.) The procedure for overlaying graphics, which uses the Scene Description panel, is described in Section Selecting the Object(s) to be Manipulated In order to manipulate the objects in the scene, you will begin by selecting the object or objects of interest in the Names list in the Scene Description panel (Figure ). The Names list is a list of the geometric objects that currently exist in the scene (including those that are presently invisible). If you select more than one object at a time, any operation (transformation, color specification, etc.) will apply to all the selected objects. You can also select objects by clicking on them in the graphics display using the mouse-probe button, which is, by default, the right mouse button. (See Section 25.3 for information about mouse button functions.) To deselect a selected object, simply click on its name in the Names list. When you select one or more objects (either in the Names list or in the display), the Type field will report the type of the selected object(s). Possible types for a single object include grid, surface, contour, vector, path, andtext (i.e., annotation text). This information is especially helpful when you need to distinguish two or more objects with the same name. When more than one object is selected, the type displayed is c Fluent Inc. November 28, 2001

77 25.5 Composing a Scene Group Changing an Object s Display Properties To enhance the scene in the graphics window, you can change the color, visibility, and other display properties of each geometric object in the scene. You can specify different colors for displaying the edges and faces of a grid object to show the underlying mesh (edges) when the faces of the grid are filled and shaded. You can also make a selected object temporarily invisible. If, for example, you are displaying the entire grid for a complicated problem, you can make objects visible or invisible to display only certain boundary zones of the grid without regenerating the grid display using the Grid Display panel. You can also use the visibility controls to manipulate geometric objects for efficient graphics display or for the creation of animations. These features, plus several others, are available in the Display Properties panel (Figure ). To set the display properties described above, select one or more objects in the Names list in the Scene Description panel and then click on the Display... button to open the Display Properties panel for that object or group of objects. Controlling Visibility There are several ways for you to control the visibility of an object. All visibility options are listed under the Visibility heading in the Display Properties panel. To make the selected object(s) invisible, turn off the Visible option. To undo invisibility, simply turn the Visible option on again. To turn the effect of lighting for the selected object(s) on or off, use the Lighting check button. You can choose to have lighting affect only certain objects instead of all of them. Note that if Lighting is turned on for an object such as a contour or vector plot, the colors in the plot will not be exactly the same as those in the colormap at the left of the display. c Fluent Inc. November 28,

78 Graphics and Visualization Figure : The Display Properties Panel c Fluent Inc. November 28, 2001

79 25.5 Composing a Scene To toggle the filled display of faces for the selected grid or surface object(s), use the Faces option. Turning Faces on here has the same effect as turning it on for the entire grid in the Grid Display panel. To turn the display of outer edges on or off, use the Outer Faces option. This option is useful for displaying both sides of a slit wall. By default, when you display a slit wall, one side will bleed through to the other. When you turn off the Outer Faces option, the display of a slit wall will show each side distinctly as you rotate the display. This option can also be useful for displaying two-sided walls (i.e., walls with fluid or solid cells on both sides). To turn the display of interior and exterior edges of the geometric object(s) on or off, use the Edges option. To turn the display of the outline of the geometric object(s) on or off, use the Perimeter Edges check button. To toggle the display of feature lines (described in Section ), if any, for the selected object(s), use the Feature Edges option. To toggle the display of the lines (if any) in the geometric object(s), use the Lines check button. Pathlines, line contours, and vectors are lines. To toggle the display of nodes (if any) in the geometric object(s), use the Nodes check button. Once you have set the appropriate display parameters, click on the Apply button to update the graphics display. Controlling Object Color and Transparency The Display Properties panel also lets you control an object s color and how transparent it is. All color and transparency options are listed under the Colors heading. To modify the color of faces, edges, or lines in the selected object(s), choose face-color, edge-color, line-color, or node-color in the Color c Fluent Inc. November 28,

80 Graphics and Visualization drop-down list. The Red, Green, and Blue color scales will show the RGB components of the face, edge or line color, which you can modify by moving the sliders on the color scales. When you are satisfied with the color specification, click on Apply to save it and update the display. The ability to set the colors for faces and edges can be useful when you wish to have a filled display for the grid or surface, but you also want to be able to see the grid lines. You can achieve this effect by specifying different colors for the faces and the edges. To set the relative transparency of an object, select face-color in the Color drop-down list. Move the slider on the Transparency scale and click on the Apply button to update the graphics display. An object with a transparency of 0 is opaque, and an object with a transparency of 100 is transparent. By specifying a high transparency value for the walls of a pipe, for example, you will be able to see contours that you have displayed on cross-sections inside the pipe. (This feature is available on all platforms when the software z buffer is used for hidden surface removal, but if your display hardware supports transparency, it will be more efficient to use the hardware z buffer as the hidden surface method instead. You can select these methods in the Display Options panel, as described in Section )! If you save a hardcopy of a display with transparent surfaces, you should not set the File Type in the Graphics Hardcopy panel to Vector Transforming Geometric Objects in a Scene When you are composing a scene in your graphics window, you might find it helpful to move a particular object from its original position or to increase or decrease its size. For example, if you have displayed contours or vectors on cross-sections of an internal flow domain (such as a pipe), you might want to translate these cross-sections so that they will appear outside of the pipe, where they can be seen and interpreted more easily. Figure shows such an example. You can also move an object by rotating it about the x, y, orz axis. If you want to display one object c Fluent Inc. November 28, 2001

81 25.5 Composing a Scene 1.50e e e e e e e e e e e-04 Z Y X Velocity Vectors in Plane Colored By Velocity Magnitude (m/s) Figure : Velocity Vectors Translated Outside the Domain for Better Viewing more prominently than the others, you can scale its size. If your geometry is rotating or has rotational symmetry, you can display the meridional view. All of these capabilities are available in the Transformations panel (Figure ). To perform the transformations described above, select one or more objects in the Names list in the Scene Description panel and then click on the Transform... button to open the Transformations panel for that object or group of objects. Translating Objects To translate the selected object(s), enter the translation distance in each direction in the X, Y, andz real number fields under Translate. (Note that you can check the domain extents in the Scale Grid panel or the Iso-Surface panel.) Translations are not cumulative, so you can easily return to a known state. To return to the original position, simply enter 0 in all three real number fields. c Fluent Inc. November 28,

82 Graphics and Visualization Figure : The Transformations Panel Rotating Objects To rotate the selected object(s), enter the number of degrees by which to rotate about each axis in the X, Y, andz integer number fields under Rotate By. (You can enter any value between 360 and 360.) By default, the rotation origin will be (0,0,0). If you want to spin an object about its own origin, or about some other point, specify the X, Y, and Z coordinates of that point under Rotate About. Rotations are not cumulative, so you can easily return to a known state. To return to the original position, simply enter 0 in all three integer number fields under Rotate By. Scaling Objects To scale the selected object(s), enter the amount by which to scale in each direction in the X, Y, andz real number fields under Scale. To avoid distortion of the object s shape, be sure to specify the same value c Fluent Inc. November 28, 2001

83 25.5 Composing a Scene for all three entries. Scaling is not cumulative, so you can easily return to a known state. To return the object to its original size, simply enter 1 in all three real number fields. Displaying the Meridional View To display the meridional view of the selected object(s), turn on the Meridional option. This option is available only for 3D models. It is applicable to cases with a defined axis of rotation and is especially useful in turbomachinery applications. The meridional transformation projects the selected entities onto a surface of constant angular coordinate, θ. The resultant projection thus lies in an (r, ζ) planewhereζ is in the direction of the rotation axis and r is normal to it. The value of θ used for the projection is taken as that corresponding to the minimum (r, ζ) point of the entity Modifying Isovalues One convenient feature that you can use to generate effective animations is the ability to generate surfaces with intermediate values between two isosurfaces with different isovalues. If the surfaces have contours, vectors, or pathlines displayed on them, FLUENT will generate and display contours, vectors, or pathlines on the intermediate surfaces that it creates. Steps for Modifying Isovalues You can modify an isosurface s isovalue directly by selecting it in the Scene Description panel s Names list or indirectly by selecting an object displayed on the isosurface. Then click on the IsoValue... button to open the IsoValue panel (Figure ) for the selected object. Note that this push button is available only if the geometric object selected in the Names list is an isosurface or a object on an isosurface (contour on an isosurface, for example); otherwise it is grayed out. In the IsoValue panel, set the new isovalue in the IsoValue field, and click on Apply. Contours, vectors, or pathlines that were displayed on the original isosurface will be displayed for the new isovalue. c Fluent Inc. November 28,

84 Graphics and Visualization Figure : The IsoValue Panel An Example of Isovalue Modification for an Animation The ability to generate intermediate surfaces with data displayed on them is especially convenient if you want to create an animation that shows data on successive slices of the problem domain. For example, if you have solved the flow through a pipe junction and you want to create an animation that moves through one of the pipes (along the y axis) and displays pressure contours on several cross-sections, you can use the following procedure: 1. Generate a surface of constant y coordinate (such as the y coordinate at the pipe inlet) using the Iso-Surface panel. 2. Use the Contours panel to generate contours of static pressure on this isosurface and manipulate the graphics display to the desired view. 3. Open the Animate panel and create key frame In the Scene Description panel, select the contour in the Names list and click on the IsoValue... push button to open the IsoValue panel. 5. Change the value of the isovalue to the y coordinate at the other end of the pipe, and click on Apply. You will see the contours of static pressure at the new y coordinate c Fluent Inc. November 28, 2001

85 25.5 Composing a Scene 6. Set key frame 10 in the Animate panel. 7. Play back the animation. When you play back the animation, FLUENT will create the intermediate frames showing contours of static pressure on the slices between the two ends of the pipe. Ten slices will be shown in succession, all with contours displayedonthem. Using the Sweep Surface panel to animate the display of contours or vectors on a surface that sweeps through the domain may be more convenient than the procedure described above. See Section for details Modifying Pathline Attributes If you are creating animations of existing pathlines, you may want to change the number of steps used in the computation of the pathlines. This allows you to animate pathlines advancing through the domain. To do so, select the pathlines in the Names list in the Scene Description panel and then click on the Path Attr... push button to open the Pathline Attributes panel (Figure ). Figure : The Pathline Attributes Panel In the Pathline Attributes panel, set the new maximum number of steps for pathline computation (Max Steps). After you change the value and click on Apply, the selected pathline will be recomputed and redrawn. c Fluent Inc. November 28,

86 Graphics and Visualization An Example of Pathline Modification for an Animation You can use the following procedure to animate pathlines from step 2 to step 101 (for example): 1. Generate the plot of pathlines using the Path Lines panel. 2. In the Scene Description panel, select the pathlines in the Names list and click on the Path Attr... push button to open the Pathline Attributes panel. 3. Change the value of the maximum number of steps to 2, and click on Apply. 4. Open the Animate panel and create key frame In the Pathline Attributes panel, change the value of the maximum number of steps to 101, and click on Apply. 6. Set key frame 100 in the Animate panel. 7. Play back the animation. When you play back the animation, FLUENT will animate the pathlines so that they advance one step in each frame Deleting an Object from the Scene If you are composing a complex scene with overlays and find that you no longer want to keep one of the objects, it is possible to delete it without affecting any of the other objects in the scene. The ability to delete individual objects is especially useful if you have overlays on and you generate an unwanted object (e.g., if you generate contours of the wrong variable). You can simply delete the unwanted object and continue your scene composition, instead of starting over from the beginning. Note that it is also possible to make objects temporarily invisible, as described in Section Object deletion is performed in the Scene Description panel (Figure ). To delete an object from the scene, select it in the Names list and then c Fluent Inc. November 28, 2001

87 25.5 Composing a Scene click on the Delete Geometry button. The selected name will disappear from the Names list, and the display will be updated immediately Adding a Bounding Frame FLUENT allows you to add a bounding frame around your displayed domain. You may also include measure markings on the bounding frame to indicate the length, height, and/or width of the domain, as shown in Figure Y X Z Figure : Graphics Display with Bounding Frame To add a bounding frame to your display, you will follow the procedure below: 1. Click on the Frame Options... button in the Scene Description panel (Figure ) to open the Bounding Frame panel (Figure ). 2. Under Frame Extents in the Bounding Frame panel, select Domain or Display to indicate whether the bounding frame should encompass the domain extents or only the portion of the domain that is shown in the display. c Fluent Inc. November 28,

88 Graphics and Visualization Figure : The Bounding Frame Panel 3. In the Axes portion of the Bounding Frame panel, specify the frame boundaries and measurements to be shown in the display:! Indicate the bounding plane(s) (e.g., the x-z and y-z planes shown in Figure ) to be displayed by clicking on the white square on the appropriate plane of the box shown under the Axes heading. (You can use any of the mouse buttons.) The square will turn red to indicate that the associated bounding plane will be displayed in the graphics window. Specify where you would like to see the measurement annotations by clicking on the appropriate edge of the box. The edge will turn red to indicate that the markings will be displayed along that edge of the displayed geometry. If you have trouble determining which square or edge corresponds to which location in your domain, you can easily find out by displaying one or two bounding planes to get your bearings. You can then select the appropriate objects to obtain the final display. 4. Click on the Display button to update the display with the current settings. If you are not satisfied with the frame, repeat steps 2 and/or 3 and click Display again. 5. Once you are satisfied with the bounding frame that is displayed, c Fluent Inc. November 28, 2001

89 25.5 Composing a Scene click on OK to close the Bounding Frame panel and save the frame settings for future displays. 6. If you wish to include the bounding frame in all subsequent displays, turn on the Draw Frame option in the Scene Description panel and click Apply. If this option is not enabled, the bounding box will appear only in the current display; it will not be redisplayed when you generate a new display (unless you have overlays enabled). The bounding planes and axis annotations will appear in the Names list of the Scene Description panel, and you can manipulate them in the same way as any other geometric object in the display. For example, you can use the Display Properties panel to change the face color of a bounding plane or to make it transparent (see Section ). c Fluent Inc. November 28,

90 Graphics and Visualization 25.6 Animating Graphics To generate animations that progress from one static view of the graphics display to the next, you can set up key frames (individual static images) using the Animate panel (Figure ). Display Animate... Figure : The Animate Panel You can compose a scene in the graphics window and define it as a single key frame. Then, modify the scene by moving or scaling objects, making some objects invisible or visible, changing colors, changing the view, or making other changes, and define the new scene as another key frame. FLUENT can then interpolate smoothly between the two frames that you defined, creating a specified number of intermediate frames. Another method of generating animations is to automatically generate surfaces with intermediate values between two isosurfaces with different isovalues. See Section for details. See Section for information about displaying the grid, contours, or vectors on a surface that c Fluent Inc. November 28, 2001

91 25.6 Animating Graphics sweeps through the domain. If you want to create a graphical animation of the solution over time, you can use the Solution Animation panel to set up the graphical displays that you want to use in the animation. See Section for details Creating an Animation You can define any number of key frames (up to 3000) to create your animation. By assigning the appropriate numbers to the key frames, you provide the information FLUENT needs to create the correct number of intermediate frames. For example, to create a simple animation that begins with a front view of an object, moves to a side view, and ends with a rear view of the object, you would follow the procedure outlined below: 1. Determine the number of frames that you want in the animation. For this example, consider the animation to be 31 frames. 2. Determine the number of key frames that you need to specify. In this example, you will specify three: one showing the front view, one showing the side view, and one showing the rear view. 3. Determine the appropriate key frame numbers to assign to the 3 specified frames. Here, the front view will be specified as key frame 1, the side view will be key frame 16, and the rear view will be key frame 31.! 4. Compose the scenes for each view to be used as a key frame. You can use the Scene Description panel (see Section 25.5) and the Views panel (see Section 25.4) to modify the display, and any other panels or commands to create contours, vectors, pathlines, etc. to be included in each scene. After you complete each scene, create the appropriate key frame by setting the Frame number and clicking on the Add button under Key Frames in the Animate panel. (See Section for special considerations related to key frame definition.) Be sure to change the Frame number before clicking on the Add button, or you will overwrite the last key frame that you created. c Fluent Inc. November 28,

92 Graphics and Visualization You can check any of the key frames that you have created by selecting it in the Keys list. The selected key frame will be displayed in the graphics window. 5. When you complete the animation, you can play it back as described in Section and/or save it as described in Section Deleting Key Frames If, during the creation of your animation, you want to remove one of the key frames that you have defined, select the key frame in the Keys list andclickonthedelete button. If you want to delete all key frames and start over again, click on the Delete All button Playing an Animation Once you have defined the key frames (as described in Section ) or read in a previously created animation file (as described in Section ), you can play back the animation and FLUENT will interpolate between the frames that you specified to complete the animation. To play the animation once through from start to finish, click on the play button under the Playback heading in the Animate panel. (The buttons function in a way similar to those on a standard video cassette player. Play is the second button from the right a single triangle pointing to the right.) To play the animation backwards once, click on the play reverse button (the second from the left a single triangle point to the left). As the animation plays, the Frame scale shows the number of the frame that is currently displayed, as well as its relative position in the entire animation. If, instead of playing the complete animation, you want to jump to a particular key frame, move the Frame slider bar to the desired frame number, and the frame corresponding to the new frame number will be displayed in the graphics window. Additional options for playing back animations are described below. Be sure to check Section as well for important notes about playing back animations c Fluent Inc. November 28, 2001

93 25.6 Animating Graphics Playing Back an Excerpt You may sometimes want to play only one portion of a long animation. To do this, you can modify the Start Frame and the End Frame under the Playback heading in the Animate panel. For example, if your animation contains 50 frames, but you want to play only frames 20 to 35, you can set Start Frame to 20 and End Frame to 35. When you play the animation, it will start at frame 20 and finish at frame 35. Fast-Forwarding the Animation You can fast-forward or fast-reverse the animation by skipping some of the frames during playback. To fast-forward the animation, you will need to set the Increment and click on the fast-forward button (the last button on the right two triangles pointing to the right). If, for example, your Start Frame is 1, your End Frame is 15, and your Increment is 2, when you click on the fast-forward button, the animation will show frames 1, 3, 5, 7, 9, 11, 13 and 15. Clicking on the fast-reverse button (the first button on the left two triangles pointing to the left) will show frames 15, 13, 11,...1. Continuous Animation If you want the playback of the animation to repeat continuously, there are two options available. To continuously play the animation from beginning to end (or from end to beginning, if you use one of the reverse play buttons), select Auto Repeat in the Playback Mode drop-down list in the Animate panel. To play the animation back and forth continuously, reversing the playback direction each time, select Auto Reverse in the Playback Mode drop-down list. To turn off the continuous playback, select Play Once in the Playback Mode list. This is the default setting. Stopping the Animation To stop the animation during playback, click on the stop button (the square in the middle of the playback control buttons). If your animation c Fluent Inc. November 28,

94 Graphics and Visualization contains very complicated scenes, there may be a slight delay before the animation stops. Advancing the Animation Frame by Frame To advance the animation manually frame by frame, use the third button from the right (a vertical bar with a triangle pointing to the right). Each time you click on this button, the next frame will be displayed in the graphics window. To reverse the animation frame by frame, use the third button from the left (a left-pointing triangle with a vertical bar). Frame-by-frame playback allows you to freeze the animation at points that are of particular interest Saving an Animation Once you have created your animation, you can save it in any of the following formats: Animation file containing the key frame descriptions Hardcopy files, each containing a frame of the animation MPEG file containing each frame of the animation Video (see Section 25.7) Animation File You can save the key frame definitions to a file that can be read back into FLUENT (see Section ) when you want to replay the animation. Since the animation file will contain only the key frame definitions, you must be sure that you have a case and data file containing the necessary surfaces and other information referred to by the key frame descriptions. To write an animation file, select Key Frames in the Write/Record Format drop-down list in the Animate panel, and click on the Write... button. In the resulting Select File dialog box, specify the name of the file and save it c Fluent Inc. November 28, 2001

95 25.6 Animating Graphics Hardcopy File You can also generate a hardcopy file for each frame in the animation. This feature allows you to save your animation frames to hardcopy files used by an external animation program such as ImageMagick. To save the animation as a hardcopy file, follow these steps: 1. Select Hardcopy Frames in the Write/Record Format drop-down list in the Animate panel.! 2. If necessary, click on the Hardcopy Options... buttontoopenthe Graphics Hardcopy panel and set the appropriate parameters for saving the hardcopy files. (If you are saving hardcopy files for use with ImageMagick, for example, you may want to select the window dump format. See Section for details.) Click Apply in the Graphics Hardcopy panel to save your modified settings. Do not click on the Save... button in the Graphics Hardcopy panel. You will save the hardcopy files from the Animate panel in the next step. 3. In the Animate panel, click on the Write... button. In the resulting Select File dialog box, specify the filename and click OK to save the files. (See Section for information about specifying filenames that increment automatically as additional hardcopies are saved.) FLUENT will replay the animation, saving each frame to a separate file. MPEG File It is also possible to save all of the frames of the animation in an MPEG file, which can be viewed using an MPEG decoder such as mpeg play. Saving the entire animation to an MPEG file will require less disk space than storing the individual window dump files (using the hardcopy method), but the MPEG file will yield lower-quality images. To save the animation to an MPEG file, follow these steps: 1. Select MPEG in the Write/Record Format drop-down list in the Animate panel. c Fluent Inc. November 28,

96 Graphics and Visualization 2. In the Animate panel, click on the Write... button. In the resulting Select File dialog box, specify the filename and click OK to save the files. FLUENT will replay the animation and save each frame to a separate scratch file, and then it will combine all the files into a single MPEG file Reading an Animation File If you have saved the key frames defining an animation to an animation file (as described in Section ), you can read that file back in at a later time (or in different session) and play the animation. Before reading in an animation file, be sure that the current case and data contain the surfaces and any other information that the key frame description refers to. To read an animation file, click on the Read... buttonintheanimate panel. In the resulting Select File dialog box, specify the name of the file to be read Notes on Animation When you are creating and playing back animations, please note the following: For smoother animations, turn on the Double Buffering option in the Display Options panel (see Section ). This will reduce screen flicker during graphics updates. When you are defining key frames, you must create all geometric objects that will be used in the animation before you create any key frames. You cannot create a key frame using one set of geometric objects and then generate a new geometry (such as a vector plot) and include that in another key frame. Create all geometric objects first, and then use the Display Properties panel to control the visibility of the objects in each key frame (see Section ). A single animation sequence can contain up to 3000 key frames c Fluent Inc. November 28, 2001

97 25.7 Creating Videos When you play back an animation, the colormap used will be the onethatiscurrentlyactive,not the one that was active during recording Creating Videos! Tools are available for creating videos from FLUENT. This section is a guide to video creation using the new video capabilities. It assumes that you have a ready-to-use video system, and that you are familiar with this system, including the special video hardware and software installed on your computer. The main use for this feature is to record an animation that you have created using the Animate panel (as described in Section 25.6). This section will describe issues involved in recording animations to video, the kind of video equipment you will need, and the procedures for creating a video using FLUENT. Video creation is not currently available in Windows versions of FLUENT Recording Animations To Video Recording an animation involves copying the computer-generated images to videotape so that you can view the animation with a VCR, or another type of tape player. This task is not an easy one, as there are several issues that should be addressed in order to create an acceptable video. A couple of these issues are described in the following sections. Computer Image vs. Video Image The computer monitor uses a different video signal than the video tape recorder (VTR). Most computers use an RGB-component, non-interlaced signal with high resolution and a high refresh rate. A VTR typically uses a standard broadcast video signal (such as NTSC or PAL), which has an interlaced, composite signal with lower resolution and a lower refresh rate. In order to send the computer image to the VTR for recording, the computer has to produce a video signal in the proper format. This requires extra hardware, which, in many cases, converts RGB component video to standard broadcast video, resulting in a lower quality image. A solution to this problem is to make sure that the image you are recording c Fluent Inc. November 28,

98 Graphics and Visualization does not have small text, or too much small detail that will be hard to see on video. Sometimes it is best to zoom in on an area of interest in a large image and animate just that portion. Another problem is that RGB-component video has a larger color space (or color gamut) than standard broadcast video. This means that some colors may get clipped when an image is converted to broadcast video, resulting in washed-out colors, or color bleeding. The solution is to try to make sure that the colors fall within the color space of the video format, and are not oversaturated. Some picture controls that can help you do this are available in FLUENT. These controls will be discussed in Section Real-Time vs. Frame-By-Frame If the images in the animation can be rendered fast enough on the computer screen, it may be possible to record the animation in real-time. This is as simple as placing the video tape recorder (VTR) in record mode, and playing the animation on the computer screen. This also requires scan-converting hardware that will convert the scan lines of the computer screen to a video signal sent to the VTR. In many cases, however, the animation cannot be played back on the computer screen in real-time. To create a video that plays the animation at a desirable speed, the animation must be recorded frame-by-frame. This involves sending one frame to the VTR, instructing it to record the frame at a specific point on the tape, then backing up the VTR to repeat the procedure with the next frame. This process takes quite a bit longer than real-time recording, but the result can be a much smoother video animation Equipment Required In general, recording an animation to video requires a system with the following hardware components: Computer with video hardware to produce the video signal c Fluent Inc. November 28, 2001

99 25.7 Creating Videos Editing VTR (video tape recorder) that supports frame-accurate recording. VTR Controller which enables computer software to control the recording process. Two VTR controller models are supported by FLUENT: the V-LAN controller developed by Videomedia, Inc., and the MiniVAS/MiniVAS-2 controller developed by the V.A.S. Group. FLUENT assumes that your recording system is set up as shown in Figure for a system with a V-LAN controller or as shown in Figure for a system with a MiniVAS controller. Computer RS-232 V-LAN Controller Editing VTR Video Composite Video Figure : Recording System with V-LAN Controller Computer RS-232 MiniVAS Controller Editing VTR Video Composite Video Figure : Recording System with MiniVAS/MiniVAS-2 Controller c Fluent Inc. November 28,

100 Graphics and Visualization Recording an Animation with FLUENT The steps for recording an animation using FLUENT are as follows: 1. Create an animation. 2. Open a connection to the VTR controller. 3. Set up your recording session. 4. Check the picture quality. 5. Make sure your tape is formatted (preblacked). 6. Start the recording session. Each step is described in detail in the following sections. Create an Animation When recording animations to video, you must first create your animation. It s also a good idea to play it back a couple times to make sure you are satisfied with it, and to save the animation key frame definitions to a file for later use (see Section ). When you are ready to record the animation, you can select Video in the Write/Record Format drop-down list found in the Animate panel. When you do so, the name of the Write... push button will change to Record..., and you can click on Record... to display the Video Control panel used for video creation. This panel can also be displayed by selecting the Video Control... menu item in the Display pull-down menu. The Video Control panel is shown below: c Fluent Inc. November 28, 2001

101 25.7 Creating Videos Open a Connection to the VTR Controller The steps for connecting to your VTR controller are as follows: 1. Select the protocol used by your VTR controller using the Protocol drop-down list. 2. Check the settings for your VTR controller by clicking on the Settings... push button. For V-LAN, this will display the V-LAN Settings panel, and for MiniVAS, it will display the MiniVAS Settings panel. 3. Select the RS-232 serial port used to connect the VTR controller to your computer. Usually, the serial port is identified by a file name such as /dev/ttyd1 for serial port 1, and /dev/ttyd2 for c Fluent Inc. November 28,

102 Graphics and Visualization serial port 2. If this is the case on your system, you can simply set the value of Port #; otherwise, you can type a new file name in the Serial Port text entry. Make sure that you have the proper UNIX read/write permissions for the file. 4. Open a connection to the VTR controller by clicking on the Open push button. If successful, a line will be printed out in the console window that reports the VTR controller protocol version and the VTR device ID. Set Up Your Recording Session Once you have established a connection to the VTR controller, you can set up your recording session. There are three types of recording sessions, as described below:! Preblack is the process of formatting a tape by laying down a time code onto the tape. A tape must be formatted before any frame-accurate editing, including frame-by-frame animation, can be performed. During this process, one usually records a black video signal onto the tape as well, thus the name preblack. When you select this option, the current graphics window will be cleared to black. You can use the window to send your black video signal to the VTR. Remember that when you preblack a previously formatted tape, a new time code will be written and any previously recorded video will be destroyed. Live Action allows you to record a live FLUENT session whichcan beused for demonstration. This option requires your computer s video hardware to have a scan converter that will send the computer display image to your VTR system. Animation will play an animation that you have created, and record it onto your VTR system. The Options... push button in the Video Control panel is used to display the Animation Recording Options panel, as shown below: c Fluent Inc. November 28, 2001

103 25.7 Creating Videos There are three parts to setting up your animation recording session: 1. Select the recording source. 2. Choose real-time or frame-by-frame recording. 3. Set the video frame hold counts. Select the Recording Source There are two possible video sources that can be used for recording an animation: Screen and Hardcopy. The choice of video source depends on what your video hardware/software provides. Here is a description of each: Screen can be used if your computer s video hardware can send all or a portion of the computer screen as a video signal to the VTR using a scan converter and associated software. With this option, you are responsible for setting up the scan converter and sending the video signal to the VTR. c Fluent Inc. November 28,

104 Graphics and Visualization Hardcopy instructs FLUENT to create a hardcopy of each frame of animation and send the hardcopy file to the computer s video hardware using a system command. This option assumes that your computer s video system includes a frame buffer that can store an image and send it as a video signal to the video recording system. When using the hardcopy option, a shell script will be called that will send the hardcopy file to the video frame buffer. The default setting is videocmd, which is a shell script that is included in your FLUENT distribution. It is located in path/fluent.inc/bin, wherepath is the directory in which you have placed the release directory, Fluent.Inc. This shell script will execute your system s command to send an image file to the video frame buffer. The script videocmd is set up to call the SGI system command memtovid. If you have a different system, you must copy the shell script videocmd to a new file and modify it to perform the proper task on your system (see the comments in videocmd for details). You can specify the name of your shell script using the Video Command text entry in the Animation Recording Options panel. In order to send a hardcopy file of the proper format to the video frame buffer, you must set up the hardcopy format using the Graphics Hardcopy panel, which can be displayed by clicking on the Hardcopy Options... push button in the Animation Recording Options panel. If you choose to perform a window dump to create the hardcopy file, the default window dump command used will also be videocmd. You can change this setting to use your own command. After setting the hardcopy options, click on Apply instead of Save... in the Graphics Hardcopy panel to apply the change. Once you have set up the hardcopy format and system command, you can test the configuration by sending the picture in the current graphics window to the video frame buffer. This is done by clicking on Preview in the Animation Recording Options panel. (Note that this is another way to send a black video signal to your VTR when you are preblacking a tape) c Fluent Inc. November 28, 2001

105 25.7 Creating Videos Choose Real-Time or Frame-By-Frame Recording There are two methods for recording an animation: real-time and frameby-frame. These methods are described below: Real-Time can be used if the animation playback speed is fast enough to provide a reasonably smooth animation in real-time. This is only available if the selected record source is Screen. Inthismode, FLUENT will simply turn VTR recording on, play the animation, then stop the recording. Frame-By-Frame is used to produce a higher-quality video animation by recording one frame at a time. For each animation frame, this method will 1) play the frame on the screen (and generate the hardcopy file, if needed), 2) preroll the VTR, and 3) record the frame. If the animation has 50 frames, this procedure is repeated 50 times, i.e., 50 record passes are made. This is the recommended method, because the real-time playback of the animation will usually be too slow and choppy. When recording in frame-by-frame mode, there is an optional setting called Frames/Pass, which can be used to try and speed up the frameby-frame recording process. It specifies the number of animation frames recorded to tape per record pass. If the animation is long enough (200 frames or more), you can try setting this value to 2 or higher. For example, if you set this value to 2 for a 202-frame animation, it will record animation frame 1 during the first pass, frames 2 and 102 during the second pass, frames 3 and 103 during the third pass, and so on. This is possible only if the animation frames can be rendered in time to be inserted onto the tape during a record pass, so use this setting with caution. Set the Video Frame Hold Counts The video standard NTSC has a frame rate of 30 frames/sec (and the PAL standard has a rate of 25 frames/sec). At the NTSC rate, a 150- frame animation will take only 5 seconds to play. To stretch out the c Fluent Inc. November 28,

106 Graphics and Visualization animation, you can record the same animation frame over 2 or more video frames. This is done by setting video frame hold counts for the beginning, middle, and end of the animation, using the Animation Recording Options panel controls described below: Begin Hold specifies the number of video frames to hold the first animation frame. It helps to hold the first frame for about 5 seconds (150 video frames for NTSC, or 125 for PAL) so that the viewer can get accustomed to the picture before the animation begins. Frame Hold specifies the number of video frames to hold each animation frame, other than the first and last. To slow down your recorded animation, try setting this value to 2 or 3. End Hold specifies the number of video frames to hold the last animation frame. You may want to hold the last animation frame for about 5 seconds to provide closure. Check the Picture Quality As described in Section , there are several sacrifices made when sending a computer image to video, including loss of color and resolution. Some steps can be taken to minimize the problem using the Picture Options panel, shown below. Display this panel by clicking on the Picture... push button in the Video Control panel c Fluent Inc. November 28, 2001

107 25.7 Creating Videos Color Use these controls to ensure that all colors fall into the proper color space for your video device. Also, for best results, set the saturation and brightness levels to 80% or less. Window Size If you have a scan converter that converts a portion of the computer screen, you can set the graphics window to a particular pixel size to match the scan converter s window size. You can also create a margin around the picture in the window to keep unwanted parts of the screen (such as the window border) out of the video image. Make Sure Your Tape is Formatted (Preblacked) Before you can start the recording session, you need to make sure the tape has been preblacked with a time code or frame code. When you start with a brand new tape, you need to take time out and preblack the whole tape first. This can be done using the following steps: 1. Rewind the tape to the beginning. c Fluent Inc. November 28,

108 Graphics and Visualization 2. Select a preblack recording session by clicking on the Preblack radio buttoninthevideo Control panel. 3. Send the VTR a black video signal using a scan converter or a hardcopy by clicking on the Preview buttonintheanimation Recording Options panel. 4. Click on the Preblack push button in the VTR Controls section of the Video Control panel to start the preblacking. Start the Recording Session Make sure you have the proper recording session selected. If you are recording an animation, the Animation radio button should be selected. To start recording onto tape, you must first go to the in point on tape where you want the recording to begin. With a blank tape, it is important to start at about 20 seconds into the tape, so the VTR has a chance to preroll up to the in point. You can use the VTR button controls to position the tape, but an easier way to go to a certain point is to type the time code or frame code in the Time or Frame counter and press the <Enter> key. For example, a time code of 00:02:36:07 is 2 minutes, 36 seconds, and 7 frames. In order to go to this position on the tape, you can enter the time code as 2:36:07, leaving out the leading zeros, or you can simply enter 23607, leaving out the leading zeros and colons. Once your tape is at the start position for your recording session, click on the Record push button to start recording General Information For other sources of information on video creation, check out these web sites on the Internet: San Diego Supercomputer Center (SDSC) Army High Performance Computing Research Center (AHPCRC) c Fluent Inc. November 28, 2001

109 25.8 Histogram and XY Plots 25.8 Histogram and XY Plots In addition to the many graphics tools already discussed, FLUENT also provides tools that allow you to generate XY plots and histograms of solution, file, and residual data. You can modify the colors, titles, legend, and axis and curve attributes to customize your plots. The following sections describe the XY and histogram plotting features in FLUENT. Section : Plot Types Section : XY Plots of Solution Data Section : XY Plots of File Data Section : XY Plots of Circumferential Averages Section : XY Plot File Format Section : Residual Plots Section : Solution Histograms Section : Modifying Axis Attributes Section : Modifying Curve Attributes Plot Types Data can be plotted in XY (abscissa/ordinate) form or histogram form. Each form is described below. XY Plots An XY (abscissa/ordinate) plot is a line and/or symbol chart of data. Virtually any defined variable or function is accessible for this type of plot. Furthermore, you may read in an externally-generated data file in order to compare your results with experimental data. You can also use the XY-plot facility to plot out the residual histories of variables, or the time histories if you have a transient problem. c Fluent Inc. November 28,

110 Graphics and Visualization FLUENT provides tools for controlling many aspects of the XY plot, including background color, legend, and axis and curve attributes. Figure shows a sample XY plot. Zones/Surfaces symmetry-3 wall e e e e-02 Static Pressure (pascal) 3.00e e e e e e Position (m) Static Pressure Figure : Sample XY Plot To differentiate the data being displayed, you can customize the pattern, color and weight of the data lines and the shape, color, and size of the data markers. When an XY plot is displayed in the graphics window, you can use any of the mouse buttons to add text annotations to the plot. (See Section for more information about the mouse-annotate function.) In addition, you can use any of the mouse buttons to move and resize the legend box. Histograms A histogram plot is a bar chart of data. It is a representation of a frequency of distribution by means of rectangles of widths representing class intervals and with areas proportional to the corresponding frequencies. When a histogram plot is displayed in the graphics window, you can c Fluent Inc. November 28, 2001

111 25.8 Histogram and XY Plots use any of the mouse buttons to add text annotations to the plot. (See Section for more information about the mouse-annotate function.) Figure shows a sample histogram Density (kg/m3) Histogram of Density Figure : Sample Histogram See Section 26.7 for information about printing histogram reports. For more information on histogram plots, see Section XY Plots of Solution Data You can produce a very sophisticated XY plot by using data from several zones, surfaces, or files and modifying the axis and curve attributes. Using the capability for loading external data files, you can create plots that compare your FLUENT results with data from other sources. To get further information about the solution, you can investigate the frequency of distribution of the data using a histogram (see Section ). Steps for Generating Solution XY Plots You can create an XY plot of solution data using the Solution XY Plot panel (Figure ). c Fluent Inc. November 28,

112 Graphics and Visualization Plot XY Plot... Figure : The Solution XY Plot Panel The basic steps for generating a solution XY plot are as follows: 1. Specify the variables(s) you are plotting: To plot a variable on the y axis as a function of position on the x axis, turn on the Position on X Axis option and choose the variable to be plotted on the y axis in the Y Axis Function drop-down list. Select a category from the upper list and then choose the desired quantity in the lower list. (See Chapter 27 for an explanation of the variables in the list.) To plot a variable on the x axis as a function of position on the y axis,turnontheposition on Y Axis option and choose the variable to be plotted on the x axis in the X Axis Function drop-down list c Fluent Inc. November 28, 2001

113 25.8 Histogram and XY Plots To plot one variable as a function of another, turn off both the Position on X Axis and Position on Y Axis options and select the variables to be plotted in the X Axis Function and YAxis Function drop-down lists. 2. Specify the plot direction: To plot a variable as a function of position along a specified direction vector, select Direction Vector in the X Axis Function or Y Axis Function drop-down list (whichever is the position axis), and specify the components of the direction vector for plotting under Plot Direction. The position axis of the plot is indicated by the selection of Position on X Axis or Position on Y Axis. The positions plotted will have coordinate values that correspond to the dot product of the data coordinate vector with the plot direction vector. For example, if you are plotting a variable at the pressure outlet of the geometry shown in Figure , you would specify the Plot Direction vector (1,0,0) since you are interested in how the variable changes as a function of x. Figure shows the resulting XY plot. (If you specified (0,1,0) as the plot direction, all variable values would be plotted at the same position (see Figure ), since the y value is the same at every point on the pressure outlet.) It is also possible to plot a variable as a function of position along the length of a specified curvilinear surface. The curvilinear surface must be piecewise linear and it cannot contain more than one closed curve, such as a complete circle. To plot a variable in this way, select Curve Length in the XAxis Function or Y Axis Function drop-down list (whichever is the position axis). Then specify the plot direction along the surface: to plot the variable along the direction of increasing curve length, select Default under Plot Direction; toplotthe variable in the direction of decreasing surface length, select Reverse. To check the direction in which the variable will be plotted along a surface, select the surface in the Surfaces list and click Show under Plot Direction. FLUENT will display the selected surface in the graphics window, marking the start of c Fluent Inc. November 28,

114 Graphics and Visualization the surface with a blue dot and the end of the surface with a red dot. FLUENT will also display arrows on the surface showing the direction in which the variable will be plotted. 3. Choose the surface(s) on which to plot data in the Surfaces list. Note that if you are plotting a variable as a function of position along the length of a curvilinear surface, you can select only one surface in the Surfaces list. 4. Set any of the options described below, or modify the attributes of the axes or curves as described in Sections and Click on the Plot button to generate the XY plot in the active graphics window. Note that you can use any of the mouse buttons to annotate the XY plot (see Section ) or move the plot legend from its default position in the upper left corner of the graphics window. Grid Fluent Inc. Thu Aug Figure : Geometry Used for XY Plot c Fluent Inc. November 28, 2001

115 25.8 Histogram and XY Plots pressure-outlet 3.00e e e+02 dyn-head 1.50e e e e Position (in) Dynamic Head Fluent Inc. Thu Aug Figure : Data Plotted at Outlet Using a Plot Direction of (1,0,0) pressure-outlet 3.00e e e+02 dyn-head 1.50e e e e Position (in) 64 Dynamic Head Fluent Inc. Thu Aug Figure : Data Plotted at Outlet Using a Plot Direction of (0,1,0) c Fluent Inc. November 28,

116 Graphics and Visualization Options for Solution XY Plots The options mentioned in the procedure above include the following. You can include data from an external file in the solution XY plot to compare your results with experimental data. You can also choose node or cell values to be plotted, and save the plot data to a file. Including External Data in the Solution XY Plot To add external data to your XY plot for comparison with your results, you must first ensure that any external data files are in the format described in Section You can then load the file(s) by clicking on the Load File... button and specifying the file(s) to be read in the resulting Select File dialog box (see Section 2.1.2). Once a file has been loaded, its title will appear in the File Data list. You can choose the data file(s) to be included in your plot from the titles in this list. To remove a file from the File Data list, select it and then click on the Free Data button. Choosing Node or Cell Values In FLUENT you can choose to display the computed cell-center values or values that have been interpolated to the nodes. By default, the Node Values option is turned on, and the interpolated values are displayed. If you prefer to display the cell values, turn the Node Values option off. Node-averaged data curves may be somewhat smoother than curves for cell values. If you are displaying the XY plot to show the effect of a porous medium or fan, to depict a shock wave, or to show any other discontinuities or jumps in the plotted variable, you should use cell values; if you use node values in such cases, the discontinuity will be smeared by the node averaging for graphics and will not be shown clearly in the plot. Saving the Plot Data to a File Once you have generated an XY plot, you may want to save the plot data to a file. You can read this file into FLUENT at a later time and c Fluent Inc. November 28, 2001

117 25.8 Histogram and XY Plots plot it alone using the File XY Plot panel, as described in Section , or add it to a plot of solution data, as described above. Tosavetheplotdatatoafile,turnontheWrite to File option in the Solution XY Plot panel. The Plot button will change to the Write... button. Clicking on the Write... button will invoke the Select File dialog box, in which you can specify a name and save a file containing the plot data. The format of this file is described in Section To sort the saved plot data in order of ascending x axis value, turn on the Order Points option in the Solution XY Plot panel before you click on the Write... button. This option is available only when the Write to File option is turned on XY Plots of File Data In addition to plots of FLUENT data, you can also plot the data contained in external files. The File XY Plot panel allows you to display data read from external files in an abscissa/ordinate plot form. The format of the plot file is described in Section Steps for Generating XY Plots of Data in External Files You can create an XY plot of data contained in one or more external files using the File XY Plot panel (Figure ). Plot File... The steps for generating a file XY plot are as follows: 1. Load each external data file (with the format described in Section ) by entering its name in the text field beneath the Files list and clicking on the Add... button (or pressing <RETURN>). If you click on Add... without specifying a name under Files (or if you specify an incorrect or duplicate name), a Select File dialog box will appear and you can specify one or more files there. When a file is loaded, its name will appear in the Files list and its title will appear in the Legend Entries list. Data in all loaded files will be plotted, so if you decide not to include one of the loaded files c Fluent Inc. November 28,

118 Graphics and Visualization Figure : The File XY Plot Panel in the plot you must select it and click on the Delete button to remove it. 2. Set any of the options described below, or modify the attributes of the axes or curves as described in Sections and Click on the Plot button to generate an XY plot of the data associated with all loaded files. Options for File XY Plots The options mentioned in the procedure above include the following. You can change the plot title, legend title, or legend entry. Changing the Plot Title The plot title will appear in the caption box at the bottom of the graphics window. You can modify the plot title by changing the entry in the Plot Title text box in the File XY Plot panel (or by editing the caption box manually, as described in Section ) c Fluent Inc. November 28, 2001

119 25.8 Histogram and XY Plots Changing the Legend Entry When you plot data from a single file, the y axis of the plot will be labeled by the legend entry. To modify this label, click on the text in the Legend Entries list, edit the text that appears in the text field below the list, and then click on the Change Legend Entry button (or hit <RETURN>). When you next plot the data, the new legend entry will appear in the plot. Changing the Legend Title When you plot data from more than one file, a legend will appear in the upper left corner of the graphics window. By default, the legend will have no title. If you want to add a title, enter it in the Legend Title text field. The title will appear above the legend the next time you plot the data. Note that you can use any of the mouse buttons to annotate the plot (see Section ) or move the legend from its default position XY Plots of Circumferential Averages You can also generate a plot of circumferential averages in FLUENT. This allows you to find the average value of a quantity at several different radial or axial positions in your model. FLUENT computes the average of the quantity over a specified circumferential area, and then plots the average against the radial or axial coordinate. Steps for Generating an XY Plot of Circumferential Averages You can generate an XY plot of circumferential averages in the radial direction using the circum-avg-radial text command: plot circum-avg-radial or you can use the circum-avg-axial text command to generate an average in the axial direction: plot circum-avg-axial c Fluent Inc. November 28,

120 Graphics and Visualization The steps for generating an XY plot of circumferential averages are as follows: 1. Specify the variable to be averaged by typing its name when FLU- ENT prompts you for averages of. You can press <RETURN> to see a list of available variables.! 2. Choose the surface on which to plot data by typing its name when FLUENT prompts you for on surface. Use the Grid Display panel to see a list of surfaces on which you can plot data. (Pressing <RETURN> will not show a list of available surfaces.) 3. Specify the number of bands to be created. (The default number of bands is 5.) FLUENT will create circumferential bands by iso-clipping the specified surface into equal bands of radial or axial coordinate. An example of the iso-clips created is shown in Figure (The radial or axial coordinate is derived from the rotation axis of the Reference Zone specifiedinthe Reference Values panel.) FLUENT then computes the average of the variable for each band using the area-weighted average described in Section Finally, it plots the average of the variable as a function of radial or axial coordinate. Figure shows an example of an XY plot of circumferential averages using radial coordinates. When the circumferential average plot is generated, FLUENT also creates a new surface called radial-bands or axial-bands, which contains the iso-clips described above (see Figure ). You can use this surface to generate other XY plots. For more information on the creation and manipulation of surfaces, see Chapter 24. Customizing the Appearance of the Plot If you want to customize the appearance of the axes or curves in a circumferential average plot, you can save the plot data to a file (using c Fluent Inc. November 28, 2001

121 25.8 Histogram and XY Plots iso-clips X Z Y Iso-Clips for Circumferential Average Figure : Iso-Clips Created For Circumferential Averaging 1.02e e e e e+05 Total Pressure 1.00e e e e e e Y X Z Radius Circumferential Averages Figure : XY Plot of Circumferential Averages c Fluent Inc. November 28,

122 Graphics and Visualization the plot-to-file text command, as described below), read the file into FLUENT and plot it again (using the File XY Plot panel, as described in Section ), and then use the Axes and Curves panels (as described in Sections and ) to modify the appearance of the plot. To save the plot data to a file,first use the plot-to-file text command to specify the name of the file. plot file-set plot-to-file Then generate the circumferential average XY plot as described above. FLUENT will display the plot in the graphics window, and also save the plot data to the specified file XY Plot File Format The XY file format read or written by FLUENT includes the following information: The title of the plot The label for the abscissa and the ordinate Cortex variables and pairs of abscissa/ordinate data for each curve in the plot The following sample file illustrates the XY file format: (title "Velocity Magnitude") (labels "Position" "Velocity Magnitude") ((xy/key/label "pressure-inlet-8") (xy/key/visible? #t) (xy/line/pattern "--") ) c Fluent Inc. November 28, 2001

123 25.8 Histogram and XY Plots Similar to the case file format, parentheses bound the various pieces of information in the formatted, ASCII file. The title (title " ") and labels (labels " ") must be first in the file, then each curve has information in the form ((cxvar value) x y x y x y...), where there may be zero or more Cortex variables defined for each curve. You do not have to include Cortex variables to import your XY data. For example, you may wish to import experimental data to compare with the FLUENT solution. The following example would use the default Cortex variables in the code to define the data. After you import the file into FLUENT, you could then use the Axes panel and the Curves panel to customize the XY plot, as described in Sections and (title "Experiment, Run 11") (labels "X, m" "Cp") ( ) Residual Plots Residual history can be displayed using an XY plot. The abscissa of the plot corresponds to the number of iterations and the ordinate corresponds to the log-scaled residual values. To plot the current residual history, click on the Plot buttoninthe Residual Monitors panel. Plot Residuals... For additional information about using the Residual Monitors panel to plot residuals, see Section Solution Histograms Histograms can be displayed in a graphics window using a bar chart (or printed in the console window, as described in Section 26.7). The c Fluent Inc. November 28,

124 Graphics and Visualization abscissa of the chart is the desired solution quantity and the ordinate is the percentage of the total number of cells. Steps for Generating Histogram Plots You can create a histogram plot of solution data using the Solution Histogram panel (Figure ). Plot Histogram... Figure : The Solution Histogram Panel The steps for generating a histogram plot are as follows: 1. Choose the scalar quantity to be plotted in the Histogram Of dropdown list. Select a category in the upper list and then select the desired quantity in the lower list. (See Chapter 27 for an explanation of the variables in the list.) 2. Set the number of data intervals that will be plotted in the histogram in the Divisions field. By default there will be 10 intervals ( bars ) in the histogram plot. If you want to resolve the histogram plot to finer intervals, increase the number of Divisions. You may want to click on the Compute button to update the Min and Max fields when you are trying to decide how many divisions to plot c Fluent Inc. November 28, 2001

125 25.8 Histogram and XY Plots 3. Set the option described below, if desired, or modify the attributes of the axes or curves as described in Sections and Click on the Plot button to generate the histogram plot in the active graphics window. Options for Histogram Plots Other than the axis and curve attribute controls mentioned in the procedure above, the only option for histogram plotting is the ability to specify a subrange of values to be plotted. Specifying the Range of Values Plotted By default, the range of values included in the histogram plot is automatically set to the range of values in the entire domain for the selected variable. If you want to focus in on a smaller range of values, you can restrict the range to be displayed. To manually set the range of values, turn off the Auto Range option in the Solution Histogram panel. The Min and Max fields will become editable, and you can enter the new range of values to be plotted. To show the default range at any time, click on the Compute button and the Min and Max fields will be updated Modifying Axis Attributes You can modify the appearance of the XY and histogram plot axes by changing the parameters that control the labels, scale, range, numbers, and major and minor rules. For each type of plot (solution XY, file XY, residual, histogram, etc.), you can set different axis parameters in the Axes panel (Figure ). Note that the title following Axes in the panel indicates which plot environment you are changing (e.g., the Axes - Solution XY Plot panel controls axis parameters for solution XY plots). To open the Axes panel for a particular plot type, click on the Axes... button in the appropriate panel (e.g., the Solution XY Plot, File XY Plot, or Residual Monitors panel). c Fluent Inc. November 28,

126 Graphics and Visualization Figure : The Axes Panel Using the Axes Panel The Axes panel allows you to independently control the characteristics of theordinate(y axis) and abscissa (x axis) on an XY plot or histogram. To set parameters for one axis or the other, you will follow the procedure below: 1. Choose the axis for which you want to modify the attributes by selecting X or Y under Axis. 2. Set the desired parameters. 3. Click on Apply and then choose the other axis and repeat the steps, if desired. Your changes to the axis attributes will appear in the graphics window the next time you generate a plot c Fluent Inc. November 28, 2001

127 25.8 Histogram and XY Plots Changing the Axis Label If you want to modify the label for the axis, you can do so by editing the Label text field in the Axes panel. Changing the Format of the Data Labels You can change the format of the labels that define the primary data divisions on the axes using the controls under the Number Format heading in the Axes panel. To display the real value with an integral and fractional part (e.g., ), select float in the Type drop-down list. You can set the number of digits in the fractional part by changing the value of Precision. To display the real value with a mantissa and exponent (e.g., 1.0e-02), select exponential in the Type drop-down list. You can define the number of digits in the fractional part of the mantissa in the Precision field. To display the real value with either float or exponential form, depending on the size of the number and the defined Precision, choose general in the Type drop-down list. Choosing Logarithmic or Decimal Scaling By default, decimal scaling is used for both axes (except for the y axis in residual plots, which uses a log scale). If you want to change to a logarithmic scale, turn on the Log option in the Axes panel. To return to a decimal scale, turn off the Log option. Note that when you are using the logarithmic scale, the Range values are the exponents; to specify a logarithmic range from 1 to 10000, for example, you will specify a minimum value of 1 and a maximum value of 4. Resetting the Range of the Axis By default, the extents of the axis will range from the minimum value plotted to the maximum value plotted. If you want to change the range c Fluent Inc. November 28,

128 Graphics and Visualization or extents of the axis, you can do so by turning off the Auto Range option in the Axes panel and setting the new Minimum and Maximum values for the Range. This feature is useful when you are generating a series of plots and you want the extents of one or both of the axes to be the same, even if the range of plotted values differs. (For example, if you are generating plots of temperature on several different wall zones, you might want the minimum and maximum temperature on the y axis to be the same in every plot so that you can easily compare one plot with another. You would determine a temperature range that includes the temperatures on all walls, and use that as the range for the y axis in each plot.) Controlling the Major and Minor Rules FLUENT allows you to display major and/or minor rules on the axes. Major and minor rules are the horizontal or vertical lines that mark, respectively, the primary and secondary data divisions and span the whole plot window to produce a grid. To add major or minor rules to the plot, turn on the Major Rules or Minor Rules option. You can then specify a color and weight for each type of rule. Under the Major Rules or Minor Rules heading, select the desired color for the lines in the Color drop-down list and specify the line thickness in the Weight field. A line of weight 1.0 is normally 1 pixel wide. A weight of 2.0 would make the line twice as thick (i.e., 2 pixels wide) Modifying Curve Attributes The data curves in XY plots and histograms can be represented by any combination of lines and markers. You can modify the attributes of the curves, including the patterns, weights, and colors of the lines, and the symbols, sizes, and colors of the markers. For each type of plot (solution XY, file XY, residual, histogram, etc.), you can set different curve parameters in the Curves panel (Figure ). Note that the title following Curves in the panel indicates which plot environment you are changing (e.g., the Curves - Solution XY Plot panel controls curve parameters for solution XY plots). To open the Curves panel for a particular plot type, click on the Curves... button in the appropriate panel (e.g., Solution XY Plot, File XY Plot, or c Fluent Inc. November 28, 2001

129 25.8 Histogram and XY Plots Figure : The Curves Panel Residual Monitors panel). Using the Curves Panel The Curves panel allows you to independently control the characteristics of each data curve in an XY plot or histogram. To set parameters for a curve, you will follow the procedure below: 1. Specify the curve for which you want to modify the attributes by increasing or decreasing the Curve # counter. The curves are numbered sequentially, starting from 0. For example, if you were plotting flow-field values on two surfaces, the first surface would be curve 0, and the second, curve 1. If the plot contains only one curve, the Curve # is set to 0 and is not editable. 2. Set the desired line and/or marker parameters as described below. 3. Click on Apply and then choose another Curve # and repeat the steps, if desired. c Fluent Inc. November 28,

130 Graphics and Visualization Your changes to the curve attributes will appear in the graphics window the next time you generate a plot. Changing the Line Style You can control the pattern, color, and weight of the line using the controls under the Line Style heading:! To set the line pattern for the curve, choose one of the items in the Pattern drop-down list. Except for center and phantom lines, the list displays examples of the pattern choices. A center line alternates a very long dash and a short dash and a phantom line alternates a very long dash and a double short dash. Note that selecting the second item in the drop-down list, represented by 4 short dashes, will result in a solid-line curve. If you do not want the data points to be connected by any type of line (i.e., if you plan to use just markers), select the blank choice, which is the first item in the Pattern list. To set the color of the line, pick one of the choices in the Color drop-down list. To define the line thickness, set the value of Weight. A line weight of 1.0 is normally 1 pixel wide. Therefore, a weight of 2.0 would make the line twice as thick (i.e., 2 pixels wide). Changing the Marker Style You can control the symbol, color, and size for the data marker using the controls under the Marker Style heading: To set the symbol used to mark data, choose one of the items in the Symbol drop-down list. The list displays examples of the symbol choices. For example, in plotting pressure-coefficient data on the upper and lower surfaces of an airfoil, the symbol /*\ (filled-in c Fluent Inc. November 28, 2001

131 25.8 Histogram and XY Plots! upward-pointing triangle) could be used for the marker representing the upper surface data, and the symbol \*/ (filled-in downwardpointing triangle) could be used for the marker representing the lower surface data. If you do not want the data points to be represented by markers (i.e., if you plan to use just a line connecting the data points), select the blank choice, which is the first item in the Style list. To set the color of the marker, pick one of the choices in the Color drop-down list. To define the size of the data marker, set the value of Size. A symbol of size 1.0 is 3.0% of the height of the display screen, except for the. symbol, which is always one pixel. Previewing the Curve Style To see what a particular setting will look like in the plot, you can preview it in the Sample window of the Curves panel. A single marker and/or line will be shown with the specified style attributes. c Fluent Inc. November 28,

132 Graphics and Visualization 25.9 Turbomachinery Postprocessing In addition to the many graphics tools already discussed, FLUENT also provides turbomachinery-specific postprocessing features, which can be accessed once you have defined the topology of the problem. Information on postprocessing for turbomachinery applications is provided in the following sections: Section : Defining the Turbomachinery Topology Section : Generating Reports of Turbomachinery Data Section : Displaying Turbomachinery Averaged Contours Section : Displaying Turbomachinery 2D Contours Section : Generating Averaged XY Plots of Turbomachinery Solution Data Section : Turbomachinery-Specific Variables Defining the Turbomachinery Topology! In order to establish the turbomachinery-specific coordinate system used in subsequent postprocessing functions, FLUENT requires you to define the topology of the flow domain. The procedure for defining the topology is described below, along with details about the boundary types. Note that the current implementation of the turbomachinery topology definition for postprocessing is limited to one row of blades at a time. If your geometry contains multiple rows of blades, you may want to define the turbomachinery topology for just one flow passage, even when the pitch is different for each blade row. However, if your geometry has multiple rows of blades, and the periodic repetition angle is the same for all the rows, you will still be able to define the topology as you would for one row of blades, and use the turbo postprocessing tools correctly. To define the turbomachinery topology in FLUENT, you will use the Turbo Topology panel (Figure ) c Fluent Inc. November 28, 2001

133 25.9 Turbomachinery Postprocessing Define Turbo Topology... Figure : The Turbo Topology Panel The steps for defining the topology for your turbomachinery application are as follows: 1. Select a boundarytype underboundaries (e.g., Hub in Figure ). The boundary types are described in detail below. 2. In the Surfaces list, choose the surface(s) that represent the boundary type you selected in step 1. If you want to select several surfaces of the same type, you can select that type in the Surface Types list instead. All of the surfaces of that type will be selected automatically in the Surfaces list (or deselected, if they are all selected already). Another shortcut is to specify a Surface Name Pattern and click Match to select surfaces c Fluent Inc. November 28,

134 Graphics and Visualization with names that match the specified pattern. For example, if you specify wall*, all surfaces whose names begin with wall (e.g., wall- 1, wall-top) will be selected automatically. If they are all selected already, they will be deselected. If you specify wall?, all surfaces whose names consist of wall followed by a single character will be selected (or deselected, if they are all selected already). 3. Repeat the steps above for all the boundary types that are relevant foryourmodel. 4. Click Apply to complete the definition of the boundaries. FLUENT will inform you that the turbomachinery postprocessing functions have been activated, and the Turbo menu will appear in FLUENT s menu bar at the top of the console window. 5. Click Display to show the defined topology in the active graphics window. This allows you to visually check the boundaries to ensure that you have defined them correctly. Note that the topology setup that you define will be saved to the case file when you save the current model. Thus, if you read this case back into FLUENT, you do not need to set up the topology again. Boundary Types The boundaries for the turbomachinery topology are as follows (see Figure ): Hub is the wall zone(s) forming the lower boundary of the flow passage (generally toward the axis of rotation of the machine). Casing is the wall zone(s) forming the upper boundary of the flow passage (away from the axis of rotation of the machine). Theta Periodic is the periodic boundary zone(s) on the circumferential boundaries of the flow passage. Theta Min and Theta Max are the wall zones at the minimum and maximum angular (θ) positions on a circumferential boundary c Fluent Inc. November 28, 2001

135 25.9 Turbomachinery Postprocessing Inlet is the inlet zone(s) through which the flow enters the passage. Outlet is the outlet zone(s) through which the flow exits the passage. Blade is the wall zone(s) that defines the blade(s) (if any). Note that these zones cannot be attached to the circumferential boundaries. For this situation, use Theta Min and Theta Max to define the blade. TOP view of passage theta periodic (periodic boundaries) inlet outlet blade theta min (wall) theta max (wall) Figure : Turbomachinery Boundary Types Generating Reports of Turbomachinery Data Once you have defined the turbomachinery topology, as described in Section , you can report a number of turbomachinery quantities, including mass flow, swirl number, torque, and efficiencies. To report turbomachinery quantities in FLUENT, you will use the Turbo Report panel (Figure ). Turbo Report... c Fluent Inc. November 28,

136 Graphics and Visualization Figure : The Turbo Report Panel c Fluent Inc. November 28, 2001

137 25.9 Turbomachinery Postprocessing The procedure for using this panel is as follows: 1. Under Averages, specify whether you want to report Mass Weighted or Area Weighted averages. 2. Click Compute. FLUENT will compute the turbomachinery quantities as described below, and display their values. 3. If you want to save the reported values to a file, click Write... and specify a name for the file in the resulting Select File dialog box. Computing Turbomachinery Quantities Mass Flow The mass flow rate through a surface is defined as follows: ṁ = A (ρ v ˆn)dA (25.9-1) where A is the area of the inlet or outlet, v is the velocity vector, ρ is the fluid density, and ˆn is a unit vector normal to the surface. Swirl Number The swirl number is defined as follows: SW = S rv θ ( v ˆn) ds r S v z ( v ˆn) ds (25.9-2) where r is the radial coordinate (specifically, the radial distance from the axis of rotation), v θ is the tangential velocity, v is the velocity vector, ˆn is a unit vector normal to the surface, S denotes the inlet or outlet, and r = 1 S S rds (25.9-3) c Fluent Inc. November 28,

138 Graphics and Visualization Average Total Pressure The area-averaged total pressure is defined as follows: p t = A p tda A (25.9-4) where p t is the total pressure and A is the area of the inlet or outlet. The mass-averaged total pressure is defined as follows: p t = A (ρp t v ˆn )da A (ρ v ˆn )da (25.9-5) where p t is the total pressure, A is the area of the inlet or outlet, v is the velocity vector, ρ is the fluid density, and ˆn is a unit vector normal to the surface. Average Total Temperature The area-averaged total temperature is defined as follows: T t = A T tda A (25.9-6) where T t is the total temperature and A is the area of the inlet or outlet. The mass-averaged total temperature is defined as follows: T t = A (ρt t v ˆn )da A (ρ v ˆn )da (25.9-7) where T t is the total temperature, A is the area of the inlet or outlet, v is the velocity vector, ρ is the fluid density, and ˆn is a unit vector normal to the surface c Fluent Inc. November 28, 2001

139 25.9 Turbomachinery Postprocessing Average Flow Angles The area-averaged flow angles are defined as follows: ( α r =tan 1 A v ) θda A v zda (25.9-8) in the radial direction, and ( α θ =tan 1 A v ) rda A v zda (25.9-9) in the tangential direction, where v z, v r, and v θ represent the axial, radial, and tangential velocities, respectively. The mass-averaged flow angles are defined as follows: ( ) α r,m =tan 1 A(ρv r)da A (ρv z)da ( ) in the radial direction, and ( ) α θ,m =tan 1 A(ρv θ)da A (ρv z)da ( ) in the tangential direction. Passage Loss Coefficient The engineering loss coefficient is defined as follows: K L = p t,i p t,o 1 2 ρv2 i ( ) where p t,i is the mass-averaged total pressure at the inlet, p t,o is the mass-averaged total pressure at the outlet, ρ is the density of the fluid, and v i is the mass-averaged velocity magnitude at the inlet. c Fluent Inc. November 28,

140 Graphics and Visualization The normalized loss coefficient is defined as follows: K L,n = p t,i p t,o p t,i p s,o ( ) where p s,o is the mass-averaged static pressure at the outlet. Axial Force The axial force on the rotating parts is defined as follows: ( F a = S ) (τ ˆn) ds â ( ) where S represents the surfaces comprising all rotating parts, τ is the total stress tensor (pressure and viscous stresses), ˆn is a unit vector normal to the surface, and â is a unit vector parallel to the axis of rotation. Torque The torque on the rotating parts is defined as follows: ( T = S ) ( r (τ ˆn)) ds â ( ) where S represents the surfaces comprising all rotating parts, τ is the total stress tensor, ˆn is a unit vector normal to the surface, r is the position vector, and â is a unit vector parallel to the axis of rotation. Efficiencies for Pumps and Compressors The definitions of the efficiencies for compressible and incompressible flows in pumps and compressors are described in this section. Efficiencies for turbines are described later in this section. Consider a pumping or compression device operating between states 1 and 2 as illustrated in Figure Work input to the device is required to achieve a specified compression of the working fluid c Fluent Inc. November 28, 2001

141 25.9 Turbomachinery Postprocessing 1 2 Work input to rotor Figure : Pump or Compressor Assuming that the processes are steady state, steady flow, and that the mass flow rates are equal at the inlet and outlet of the device (no film cooling, bleed air removal, etc.), the efficiencies for incompressible and compressible flows are as described below. Incompressible Flows For devices such as liquid pumps and fans at low speeds, the working fluid can be treated as incompressible. The efficiency of a pumping process with an incompressible working fluid is defined as the ratio of the head rise achieved by the fluid to the power supplied to the rotor/impeller. This can be expressed as follows: η = Q(p t2 p t1 ) Tω ( ) where Q = volumetric flow rate p t = total pressure T = net torque acting on the rotor/impeller ω = rotational speed This definition is sometimes called the hydraulic efficiency. Often, other efficiencies are included to account for flow leakage (volumetric c Fluent Inc. November 28,

142 Graphics and Visualization efficiency) and mechanical losses along the transmission system between the rotor and the machine providing the power for the rotor/impeller (mechanical efficiency). Incorporating these losses then yields a total efficiency for the system. Compressible Flows For gas compressors that operate at high speeds and high pressure ratios, the compressibility of the working fluid must be taken into account. The efficiency of a compression process with a compressible working fluid is defined as the ratio of the work required for an ideal (reversible) compression process to the actual work input. This assumes the compression process occurs between states 1 and 2 for a given pressure ratio. Inmost cases, the pressure ratio is the total pressure at state 2 divided by the total pressure at state 1. If the process is also adiabatic, then the ideal state at 2 is the isentropic state. From the foregoing definition, the efficiency for an adiabatic compression process can be written as where η c = h t2,i h t1 h t2 h t1 ( ) h t1 = total enthalpy at 1 h t2 = actual total enthalpy at 2 h t2,i = isentropic total enthalpy at 2 If the specific heat is constant, Equation can also be expressed as η c = T t2,i T t1 T t2 T t1 ( ) where T t1 = total temperature at 1 T t2 = actual total temperature at 2 T t2,i = isentropic total temperature at c Fluent Inc. November 28, 2001

143 25.9 Turbomachinery Postprocessing Using the isentropic relation T t2,i T t1 = ( pt2 p t1 ) γ 1 γ ( ) where γ is the ratio of specific heats specified in the Reference Values panel. the efficiency can be written in the compact form η c = [ ] ( ) γ 1 T pt2 γ t1 p t1 1 T t2 T t1 ( ) Note that this definition requires data only for the actual states 1 and 2. Compressor designers also make use of the polytropic efficiency when comparing one compressor with another. The polytropic efficiency is defined as follows: η c,p = ( ) γ 1 γ ln pt2 p ( ) t1 ( ) ln Tt2 T t1 Efficiencies for Turbines Consider a turbine operating between states 1 and 2 in Figure Work is extracted from the working fluid as it expands through the turbine. Assuming that the processes are steady state, steady flow, and that the mass flow rates are equal at the inlet and outlet of the device (no film cooling, bleed air removal, etc.), turbine efficiencies for incompressible and compressible flows are as described below. Incompressible Flows The efficiency of a turbine with an incompressible working fluid is defined as the ratio of the work delivered to the rotor to the energy available from the fluid stream. This ratio can be expressed as follows: c Fluent Inc. November 28,

144 Graphics and Visualization 1 2 Figure : Turbine Work output from rotor η = Tω Q(p t1 p t2 ) ( ) where Q = volumetric flow rate p t = total pressure T = net torque acting on the rotor/impeller ω = rotational speed Note the similarity between this definition and the definition of incompressible compression efficiency (Equation ). As with hydraulic pumps and compressors, other efficiencies (e.g., volumetric and mechanical efficiencies) can be defined to account for other losses in the system. Compressible Flows For high-speed gas turbines operating at large expansion pressure ratios, compressibility must be accounted for. The efficiency of an expansion process with a compressible working fluid is defined as the ratio of the actual work extracted from the fluid to the work extracted from an ideal (reversible) process. This assumes that the expansion process occurs between states 1 and 2 for a given pressure ratio. In contrast to the compression process, the pressure ratio for expansion is the total pressure c Fluent Inc. November 28, 2001

145 25.9 Turbomachinery Postprocessing at state 1 divided by the total pressure at state 2. Iftheprocessisalso adiabatic, then the ideal state at 2 is the isentropic state. From the foregoing definition, the efficiency for an adiabatic expansion process through a turbine can be written as where η c = h t1 h t2 h t1 h t2,i ( ) h t1 = total enthalpy at 1 h t2 = actual total enthalpy at 2 h t2,i = isentropic total enthalpy at 2 If the specific heat is constant, Equation can also be expressed as where η e = T t1 T t2 T t1 T t2,i ( ) T t1 = total temperature at 1 T t2 = actual total temperature at 2 T t2,i = isentropic total temperature at 2 Using the isentropic relation T t1 T t2,i = ( pt1 p t2 ) γ 1 γ ( ) the expansion efficiency can be written in the compact form η e = T t1 T t2 ] ( ) ( ) γ 1 T t1 [1 pt2 γ p t1 Note that this definition requires data only for the actual states 1 and 2. c Fluent Inc. November 28,

146 Graphics and Visualization As with compressors, one may also define a polytropic efficiency for turbines. The polytropic efficiency is defined as follows: η e,p = ( ) ln Tt1 T t2 ( ) γ 1 γ ln ( ) pt1 p t Displaying Turbomachinery Averaged Contours Turbo averaged contours are generated as projections of the values of a variable averaged in the circumferential direction and visualized on an r-z plane. A sample plot is shown in Figure Steps for Generating Turbomachinery Averaged Contour Plots You can display contours using the Turbo Averaged Contours panel (Figure ). Turbo Averaged Contours... Figure : The Turbo Averaged Contours Panel The basic steps for generating a turbo averaged contour plot are as follows: c Fluent Inc. November 28, 2001

147 25.9 Turbomachinery Postprocessing 1. Select the variable or function to be displayed in the Contours Of drop-down list. First select the desired category in the upper list; you may then select a related quantity in the lower list. (See Section for a list of turbomachinery-specific variables, and see Chapter 27 for an explanation of the variables in the list.) 2. Specify the number of contours in the Levels field. The maximum number of levels allowed is Set any of the options described below. 4. Click on the Display button to draw the specified contours in the active graphics window. The resulting display will include the specified number of contours of the selected variable, with the magnitude on each one determined by equally incrementing between the values shown in the Min and Max fields. Note that the Min and Max values displayed in the panel are the minimum and maximum averaged values. These limits will in general be different from the global Domain Min and Domain Max, whicharealso displayed for your reference (see Figure ). Contour Plot Options The options mentioned in the procedure above include drawing colorfilled contours (instead of line contours), specifying a range of values to be contoured, and storing the contour plot settings. These options are the same as those in the standard Contours panel. See Section for details about using them. c Fluent Inc. November 28,

148 Graphics and Visualization 1.80e e e e e e-01 Y Z X Averaged Turbo Contour - pressure (atm) (atm) Figure : Turbo Averaged Filled Contours of Static Pressure c Fluent Inc. November 28, 2001

149 25.9 Turbomachinery Postprocessing Displaying Turbomachinery 2D Contours In postprocessing a turbomachinery solution, it is often desirable to display contours on surfaces of constant pitchwise, spanwise, or meridional coordinate, and then project these contours onto a plane. This permits easier evaluation of the contours, especially for surfaces that are highly three-dimensional. Steps for Generating Turbo 2D Contour Plots You can display contours usingtheturbo 2D Contours panel (Figure ). Turbo 2D Contours... Figure : The Turbo 2D Contours Panel The basic steps for generating a turbo 2D contour plot are as follows: 1. Specify whether you want to generate the contour plot on a surface c Fluent Inc. November 28,

150 Graphics and Visualization of constant pitchwise value, spanwise value, or meridional value by selecting Pitchwise Value, Spanwise Value, ormeridional Value under Surface of Constant. 2. Enter a value for the fractional distance along the surface where you want to create the contour plot in the Fractional Distance field. The definition of the fractional distance depends on your selection under Surface of Constant: If you selected Pitchwise Value in step 1, the fractional distance is Blade to Blade (fractional distance between the two blades). If you selected Spanwise Value, the fractional distance is Hub to Casing. If you selected Meridional Value, the fractional distance is Inlet to Outlet. 3. Select the variable or function to be displayed in the Contours Of drop-down list. First select the desired category in the upper list; you may then select a related quantity in the lower list. (See Section for a list of turbomachinery-specific variables, and see Chapter 27 for an explanation of the variables in the list.) 4. Specify the number of contours in the Levels field. The maximum number of levels allowed is Select the Projection Direction. The choices are Axial, Radial, and Normalized Coordinates. 6. Set any of the options described below. 7. Click on the Display button to draw the specified contours in the active graphics window. The resulting display will include the specified number of contours of the selected variable, with the magnitude on each one determined by equally incrementing between the values shown in the Min and Max fields c Fluent Inc. November 28, 2001

151 25.9 Turbomachinery Postprocessing Contour Plot Options The options mentioned in the procedure above include drawing colorfilled contours (instead of line contours), specifying a range of values to be contoured, and storing the contour plot settings. These options are the same as those in the standard Contours panel. See Section for details about using them Generating Averaged XY Plots of Turbomachinery Solution Data When comparing numerical solutions of turbomachinery problems to experimental data, it is often useful to plot circumferentially averaged quantities in the spanwise and meridional directions. This section describes how to do this in FLUENT. Steps for Generating Turbo Averaged XY Plots To create an XY plot of circumferentially averaged solution data, you will use the Turbo Averaged XY Plot panel (Figure ). Turbo Averaged XY Plot... Figure : The Turbo Averaged XY Plot Panel The basic steps for generating a a turbo averaged XY plot are as follows: c Fluent Inc. November 28,