[clef1]

Hello everybody,

I am working in a relatively simple task (calculation of drag coefficient of 2D cylinder) and I am using a mesh that has a y+ < 5. Therefore, I won’t use Wall Functions (at least log-law wall functions).

I have been searching through the forum (and outside of it) to find what are the B.C for this case, for low values of y+, but I couldn’t find a clear answer.

I am working with k-omega SST turbulence model. Can someone please explain what B.C I must use for my cylinder wall in k, omega and nut?

Thank you,

[talop]

Hi clef1,

The "lowReWallFunction" did the trick for me.
https://www.openfoam.com/documentati...lFunction.html

Similar BCs exist for others as well. Try the banana trick to see the list of available BCs and run a google search for interesting ones.

You can also try 3D unsteady RANS and DES. They tend to give better results for this problem.

Best

[clef1]

Originally Posted by talop

Hi clef1,

The "lowReWallFunction" did the trick for me.
https://www.openfoam.com/documentati...lFunction.html

Similar BCs exist for others as well. Try the banana trick to see the list of available BCs and run a google search for interesting ones.

You can also try 3D unsteady RANS and DES. They tend to give better results for this problem.

Best

Dear Talop,

Thank you for your reply,

It seems that some k and nut (and omega) wall functions are adjusted depending on y+, therefore we can use them throught the range of y+.

I will check your comments,

Thanks