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CFD Simulation Issues with Car Outline

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Old   November 4, 2010, 23:43
Default CFD Simulation Issues with Car Outline
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Hey guys,

I am working on a project where I would like to test the effects of a splitter on the overall down-force on the front of a car. I have built the mesh in GAMBIT, and it is attached in the thread "No Splitter Gambit Mesh.jpg". I have tried several different model types and solution methods, I have done some research on several different methods that would pertain to this sort of simulation but everything that I try keeps giving me a convergence error, or divergence occurs because the continuity of the iterations keeps sky-rocketing instead of leveling out.

If anyone has any suggestions as to what I may be doing wrong? Maybe the mesh isn't correctly set up?

Also, part of what may be sort of affecting this is the fact that the car outline is not simply suspended in the air, there is a "ground" below it known as a "wall" and I don't know if that might be affecting it either.

If anyone has any ideas, your help will be greatly appreciated!!

Thanks in advance,

Active Aero Fiero
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File Type: jpg No Splitter Gambit Mesh.jpg (98.0 KB, 32 views)
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Old   November 5, 2010, 02:52
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Maxime Perelli
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Check tutorial 5 on Gambit (Sedan Geometry - Virtual Clean Up) especially Boundary Conditions.
I would also extend your domain (which is too close from your car)
In memory of my friend Hervé: CFD engineer & freerider
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Old   November 7, 2010, 19:47
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Hey Max,

I tried the tutorial, it is meant for a 3D so I tried it on a different part (an airfoil) just to see if it would work using their steps. I got the 3D mesh to work...albeit it was rather large and complained about insufficient memory... Then when I tried to import the mesh into FLUENT it tells me that under 3D it cannot read face meshes?? Although I double checked and it was only a volume mesh... so this leads me to wonder where the face mesh is coming from...

In regards to the 2D car outline model, I tried expanding the front, top and rear extent of the mesh, still keeping the ground at the same level as it was before because that is the vehicle's clearance to the ground. I tried the tutorial's methods for boundary conditions (but the inlet as a pressure inlet doesn't make much sense?) How do you set a flow velocity for that?

Any more help in regards to these problems would be greatly appreciated!

Thanks in advance

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Old   November 8, 2010, 02:25
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What are the boundary conditions in your first picture?
Also your domain at the back seems very little.
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