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k-epsilon, Stagnation point, high Re, steady state.

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Old   May 19, 2017, 21:25
Question k-epsilon, Stagnation point, high Re, steady state.
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Anders Utnes
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Hi

Is there any standard solver I can use for this case:

I have a steady state geometry with a stagnation point, and high reynolds number (10^5). I need to accurately predict the dragcoefficient for the geometry.

I was planing to test k-epsilon in simpleFoam, but I dont know how to avoid the stagnation point anamoly.
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Old   May 20, 2017, 02:38
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Uwe Pilz
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Prediction pressures at higher Re is not an easy task. I recommend to start with a geometry where experimental data are available. Often the flow past a cylinder is used, for which the drag an lift coefficients are known.

If you have a decent mesh, RANS simulation usual give quite accurate results, even in 2D. You have to check whether the results stay nearly constant when you make the mesh finer. If you need taking into account more turbulence effects and have to switch to LES, you need a 3D mesh or at least a 2,5D mesh (a 2D mesh expanded to some degree in the third dimension).
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