Transcription

1 Plan for today (two exercises) 1: CAD, CFD, FEM Fluid-Structure interaction (FSI) Numerical Methods in Aerodynamics Create an object in SolidWorks (CAD) Transfer the object to ANSYS Workbench Generate a wind tunnel inclosure Generate a fluid flow mesh Apply boundary conditions Apply initial conditions Solve the flow around the object Generate flow results Solve the structural model mesh, material, supports, pressure load from the fluid solution Change the system and update the solution 1

2 Plan for today (two exercises) 2: Indoor Create room with mechanical inlet Define variables for the inlet properties Generate a fluid mesh of the room Apply boundary conditions Apply initial conditions Solve the flow in the room Generate flow results Change the boundary conditions Numerical Methods in Aerodynamics 2

3 Problem 1: Combining CAD, CFD and FEM Numerical Methods in Aerodynamics Solve the deformations due to flow pressure Change the width of the structural element Inflow steel part Fixed support 3

4 Create object in Solidworks Numerical Methods in Aerodynamics 4

5 ANSYS Workbench an overview of the various parts in the project 5

6 Wind tunnel enclosure in DesignModeler Numerical Methods in Aerodynamics 6

7 Generating the mesh for the fluid flow applying boundary conditions in CFX Pre 7

8 Solve the fluid flow i CFX Solver Numerical Methods in Aerodynamics 8

9 Illustrate flow results in CFX Post Numerical Methods in Aerodynamics 9

10 Pressure result on boundary Numerical Methods in Aerodynamics 10

11 Transfer pressure from CFX to ANSYS structural solver and solve for deformations 11

12 Solution of structural analysis Numerical Methods in Aerodynamics 12

13 Change the system Change the CAD model Update the geometry in CFX Update the mesh Adopt the boundary conditions from previous simulation Solve for pressure Update the geometry in the FEM model Import the updated pressure Solve the structural system 13

14 Problem 2: Indoor solution Numerical Methods in Aerodynamics 14

15 Create the model Start SolidWorks (SW) Create a new "part" Chose "Top plane" press "Sketch" press "rectangle" 15

16 Create rectangle Create a rectangle from the origo press "smart dimension", click on the right and top side of the rectangle and enter dimension=1m press "zoom to fit" Close the sketch and accept by clicking in the upper right corner 16

17 Extrude press "features" and mark the sketch, press "Extruded Boss" Extrude 5m and accept 17

18 Camfer the roof Press "Features" and "Chamfer" Chose top face of extruded shape D=0.3m, angle = 45 degrees, accept 18

19 Save and transfer to Workbench Numerical Methods in Aerodynamics Save the part as "test1" > ANSYS 11.0 > Workbench NB! SolidWorks should be installed first in order to have the ANSYS menu bar. Rerun the ANSYS installation and include the Solidworks geometry interface, if it is missing 19

20 ANSYS Workbench Open an empty project Link to Active CAD Geometry test1.sldrt New Geometry (This is already done if transfered directly from SW) 20

21 DesignModeler New Geometry Press "Generate" to import the SW part Choose Attach1 >tools>freeze For the tunnel part not to merge with the element Create a wind tunnel inclosure ZXPlane Sketching Make rectangle (any size) The rectangle should have a corner in each quadrant 21

22 Set dimensions of the enclosure Choose dimensions, Length/distance L1 (positive x-direction) mm L2 (negative x-direction) mm L3 (positive z-direction) mm L4 (negative z-direction) mm 22

23 Extrude the tunnel and cut out the body Extrude FD = mm (Generate to see result) Cut out the body to leave just the region of interest for the CFD Choose create>body operations Set Type to cut material and bodies to "test1" (select in the tree view or box select) Generate to see result Save and return to "project" tab 23

24 Generate the mesh (CFX-Mesh) Generate regions Right-click on regions>insert>composite 2D regions Name Inlet (YZ low x), name outlet (YZ high X), name Free (top and two sides, use ctrl to mark several surfaces), name building is the body (choose with box select), name wall (XZ low Y) Inlet Free outlet Building Wall 24

25 Setting up the mesh Define a maximum spacing Default body spacing, maximum spacing = 1600mm Finer mesh around the body Right-click spacing>insert>face Spacing Select the body, apply Face Spacing Type: constant Constant edge length: 200 mm Boundary layer around body and wall Right-click inflation>insert>inflated boundary choose body and wall (hold ctrl) set Maximum thickness: 50 mm 25

26 Previewing the mesh, generate the mesh Right-click on preview>insert>preview group Choose Free, Wall, Body > apply Right-click on the preview>generate this surface mesh Click on "generate the volume mesh for the current problem" Return to the "Project" tab Free Body Inflation layer Wall 26

27 Start the Advanced CFD (CFX-pre) Create a domain "test1" Numerical Methods in Aerodynamics General option: Domain models>pressure>reference pressure : 1 atm Fluid models: Heat Transfer Model>option Isothermal: Fluid temperature: 25 C Turbulence model>option: shear stress transport 27

28 Creating the boundary conditions Click "create boundary condition": Inlet Basic settings Boundary type: Inlet Location: Inlet Boundary details Mass and Momentum>Normal speed: 15 m/s Turbulence>option: Intensity and length scale Turbulence>medium turbulence intensity Click "create boundary condition": Outlet Basic settings Boundary type: Outlet Location: Outlet Boundary details Mass and Momentum>Option: Static pressure Mass and Momentum>Relative Pressure: 0 Pa 28

29 Click "create boundary condition": Free Basic settings Boundary type: Wall Location: Free Boundary details Wall Influence on Flow>Option: Free Slip Click "create boundary condition": Wall Basic settings Boundary type: Wall Location: Wall Boundary details Wall Influence on Flow>Option: No Slip Click "create boundary condition": Building Basic settings Boundary type: Wall Location: Building Boundary details Wall Influence on Flow>Option: No Slip Numerical Methods in Aerodynamics 29

30 Setting initial values, solver control, and start the solver Click "Define the global initial conditions": Cartesian Velocity components>option: Automatic with value U = 15 m/s V = 0 m/s W = 0 m/s Turbulence Eddy Dissipation: select Click "Define the solver control criteria": Convergence control Timescale control: automatic timescale Timescale factor: 1 s Max. iterations: 100 Click "Write solver file": Operation: Start solver manager 30

31 Viewing results Choose "CFX Post", load result (*.res file) Creating a sample plane, click location>plane Definition: points and normal, point (1.5, 3, -0.5), normal (1, 0, 0) Plane bounds: rectangular (x-size=6 m, y-size=3 m) Plane type, sample (x-sample=50, y-sample=20) 31

32 Vector plot of velocities, etc. Click "create vector plot" Location: plane 1 Numerical Methods in Aerodynamics Variable: velocity Same approach for other planes try "contour" or "streamline" To see pressure on body create a new contour, location: building For an animation click "show animation editor" 32

33 Structural analysis Create a new project link to active CAD geometry (Part1) and press "New simulation" Run the structural simulation Wizard 33

34 Export body pressure to finite element model Stress analysis > static structural 34

35 Structural loads Mark the building (not the bottom) Numerical Methods in Aerodynamics CFX loads > CFX pressure (browse for the res-file) Apply supports (fixed at bottom) Right-click on solution and insert deformation>total solve 35

36 Viewing the results Click "total deformations" Choose a scale factor 5xauto Choose edges>show undeformed model Click animation fan for animation of the result 36

37 Change the model in SW Double-click on the sketch Double-click on the z-dimension change to 2 m Update by clicking "rebuild" 37

38 Update the CFX-designModeler Numerical Methods in Aerodynamics Open the DesignModeler Choose the attached geometry Refresh>Using DesignModeler parameter values Click "generate" The new geometry is now included in the model 38

39 Update the CFX-mesh Click "update the geometry from its original source" Look at the preview group (right-click and generate) Generate a new volume mesh save as "test2" 39

40 Update the CFX-pre Press the "project" tab. Choose the CFX-pre file (building.cfx) Re-read mesh file, file to load "building2.gtm" Click "Write solver file": Operation: Start solver manager 40

41 Update the CFX-post Open the CFX-post (*.cst) Load results (test2_001.res) 41

42 Update and solve the finite element model Numerical Methods in Aerodynamics Open the structural simulation Update the geometry 42

43 Update and solve the finite element model Update the pressure choose define as>cfx Results Correct the filename to "building_002.res" "Solve" 43

44 Thank you for your attention 44