Tutorials from CAD through CFD for Beginners

Transcription

1 Tutorials from CAD through CFD for Beginners John M. Cimbala, Professor Keith A. Martin, Graduate student Scott A. Richards, Graduate student Department of Mechanical and Nuclear Engineering, The Pennsylvania State University ISTEC Meeting, Cornell University July 22-23, 2011, Ithaca, NY

2 Introduction Computational Fluid Dynamics requires 4 steps: Geometry (database) creation Grid (mesh) generation CFD setup, and then calculation (simulation) Post-processing and analysis In some cases (if not within ANSYS Workbench), each step is performed with separate software! Each software package has a significant and sometimes steep learning curve. In order for undergraduates to have meaningful CFD exposure, good tutorials are essential.

3 Problems with Existing Tutorials Many of the mesh generation tutorials supplied by software companies start with pre-made CAD files that need to be imported. Many of the CFD tutorials supplied by software companies start with pre-made mesh files that need to be imported. Generally lacking is a holistic approach that starts with CAD, moves to mesh generation, progresses to CFD, and finishes with post-processing.

4 Objectives Create tutorials that do not rely on pre-made CAD files or mesh files, but are self-contained. Create tutorials that cover all four steps in CFD (cradle to grave): Create geometry (CAD) Create mesh Set up and run CFD simulation Post-process and analyze results Create tutorials that are easy to follow, especially for beginning students.

5 Software used in the Tutorials Creating the geometry: Workbench or Pointwise: Create geometry before or while doing mesh generation SolidWorks CAD package used by Penn State undergrads; site license available Creating the mesh: Workbench or Pointwise Setting up and running the CFD simulation: Workbench, stand-alone FLUENT, or OpenFOAM Analysis and post-processing: Workbench, stand-alone FLUENT, or third-party software that comes with OpenFOAM

6 Completed Tutorials All of our tutorials are located at: >> Teaching >> Professor Cimbala s Learning Modules and Tutorials ANSYS Workbench tutorials online at present: Flat plate boundary layer Flow over a 2-D airfoil Minor losses in a pipe elbow General CFD tutorials online at present: Laminar pipe flow: Pointwise and OpenFOAM Minor losses, turbulent pipe with elbow: SolidWorks, Pointwise, and FLUENT Minor losses, turbulent pipe with elbow: SolidWorks, Pointwise, and OpenFOAM

7 Walk through some Tutorials At this point, we will go to the website and walk through some of the tutorials: Tutorial instructions generated in MS Word, then saved as pdf files Tutorials use consistent format and icons Tutorials include lots of pictures and screenshots to guide the beginning student Example for ANSYS Workbench: Boundary Layer on a Flat Plate Stay entirely within the Workbench environment Example for General CFD: Minor Losses through a Pipe Elbow Use SolidWorks, Pointwise, and OpenFOAM

8 Walk through some Tutorials

9 Observations and Problems Tutorials take a long time to create: Step by step instructions are quite tedious to generate Best to have (good) student help! Must edit several times to get all the details right Problems with these tutorials: Only fairly simple geometries/flows can be used; otherwise the tutorials get too long. Software upgrades: When new versions of the software are installed, some of the steps become obsolete or incorrect (different wording, icons, etc.). Must go through tutorial carefully to find changes. Is there a way around the problem of having to update tutorials for every new software version?

10 Summary and Conclusions We have attempted to create tutorials that are self-contained, covering all four steps of CFD: Create geometry Create mesh Set up and run CFD simulation Post-process and analyze results Several tutorials have been posted: Follow consistent format and symbols/icons Step-by-step instructions Major problems with these tutorials: Very long; tedious to generate and edit Must update tutorials for new software versions

11 Questions or Comments?

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