Hello,
Recently I came across an accurate modle of a Porsche 944 and I desided to do a CFD analysis in order to calculate the Cd and Cl. Now I ran the simulation and got a 45% error on ther Cd (0.33 Claimed, 0.5 Measured). I relize that it wont be perfect because the model isn't 100% accurate, however, I would happy with at least a 10% error.
During the simulation i set the initial air velocity to 160 km/h however, when the simulation finished the air velocity was 136 km/h. I dont understant how this happens because I set the velocity as a constant.
From what I have read so far the mesh is KEY to have accurate results. So basically I need help setting up my mesh.
Mesh Info:
| Refinement | Level |
|---|---|
| Curvature Refinement Level | 4 |
| Tolerence Refinement Level | 3 |
| Refine Fluid Cells | 2 |
| Refine Partial Cells | 4 |
| Refine All Cells | - |
| Narrow Channels Refinement Level | 1 |
| Initial Mesh Level | 7 |
If you need any more information just let me. I can also provide the actul CAD model and pictures if needed.
I would greatly appreciate any information you guys can provide and thanks in advance.
Thanks,
Mark
pretty complicated analysis
consider your cad geometry's accuracy vs what was tested in the wind tunnel
fluid properties...etc.
did you have a moving floor...etc.
what's your long term goal here? i might suggest starting with a simpler model like a wing shape that has a known answer and is simple enough to run and troubleshoot. once you have a good understanding of the software you can move to a more complicated problem.
there are a bunch of really good articles about this type of analysis in the solidworks KB.