odd results of kOmega SST and small yPlus
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Hi Cfd-Online!
I'm a newbie in OpenFOAM world and happen to submit weekly projects since last month! I' trying to simulate a very simple problem and geometry with kOmegaSST model in "simpleFoam" but the results are odd to me! The geometry as you can see in attachment is a semi-orifice form and the fluid is water at 25ºC and gotta simulate it for Re=30 and Re=3000! I dont use a fine mesh [Overall number of cells of each type : hexahedra: 40000] . With SST model i'm getting very small yPlus number for Re=3000 and Re=30 for example here are the results for Re=3000: Quote:
Both cases dont converge after 10000 interval which might be okay for Re=3000 but odd for Re=30, although after 8000 you dont see that much change in numbers. what do you thing about y+ and also k,Omega, nut behavior ? here are the conditions: U: Quote:
P: Quote:
Omega: Quote:
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nut: Quote:
fvSolution: Quote:
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Hi,
check this to better understand what you're trying to do: https://www.brighthubengineering.com...urbulent-flow/ Calculate the turbulence properties using e.g.: https://www.cfd-online.com/Tools/turbulence.php Dig a bit deeper into y+ ranges and mesh densities/properties suitable for your cases i.e. internal flow at your cases Re numbers. Calculate y+ wall distance using e.g.: https://www.cfd-online.com/Tools/yplus.php And create a mesh that meets the y+ wall distance requirement for your case Re = 3000 should be a turbulent case and kOmegaSST should work Re = 30 should be a laminar flow case so maybe switch off turbulence in the constant/turbulenceProperties file Code:
simulationType RAS; |
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