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Old   April 21, 2011, 11:16
Exclamation Issue with transition models
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Kisorthman Vimalakanthan
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Hi guys,

Im trying to simulate a 2D flow around the S809 airfoil (see attached picture). Flow reynolds number is 2 million (2D grid with unity depth). Im using the SST gama theta transition model for my simulation, currently I have been faced with an unknown problem. A grid consisting of 1 million elements was used. The simulation was run for 5000 iterations (convergence history is attached). The turbulence intensity of 0.03% was used. Unusually the wall shear stress distribution (see attached picture) suggests a cross flow between the two ends of the wing (symmetry conditions). Because of this two different distribution of shear stress is obtained at the suction(top) surface. I was wondering if anyone else faced the same issue with the gama theta SST model. If so could you please tell me where I'm going wrong and please suggests a way to solve this problem.

Any help on this matter is greatly appreciated.

Thanks in advance

Screen shot 2011-04-21 at 16.07.22.png, Screen shot 2011-04-21 at 15.51.05.jpg

WallShear.jpg, TT.png

Mesh2.jpg

Last edited by k.vimalakanthan; April 22, 2011 at 08:34. Reason: picture change
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Old   April 26, 2011, 22:15
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Glenn Horrocks
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Looks like you problem is more to do with this FAQ:

http://www.cfd-online.com/Wiki/Ansys...gence_criteria
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cfx 12.1, gama theta, s809, sst, transition model

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