wall functions for RAS models
 

Hi everyone,

is there a way to turn off the wall functions for the turbulent quantities in OpenFOAM 1.6? I'm a bit confused about this. I know that the RAS-models should be used with wall functions. But i want to compare the result with and without them to see the difference. Together with refining of my mesh.

Thank you in advance, Eric

Hi,

maybe you can use "calculated" instead of (for example) "nutWallFunction" in the nut-file of your 0-directory!
But I'm not sure...

Hi,

I tested it in the pitzDaily-tutorial and it worked (but I didn't checked the results)!
I think you also have to change the boundary conditions for k and epsilon in 0-directory! I used zeroGradient instead of kqRWallFunction and epsilonWallFunction!

Hi,

you can use several provided RANS turbulence models without (log-law) wall functions. At least on can use the k-omega and k-omega-SST models. There is also a modified k-epsilon model for that purpose, the launder sharma KE.

If you are using the k-omega-SST model, I can tell you my setup for low-Re wall-treatment.
For boundary conditions at the wall, k=0, mut=0, omega=omegaWallFunction.

Note, that there is a new omegaWallFunction (very nice!) for low-Re wall-treatment. Therefore have a look at this thread.
http://www.cfd-online.com/Forums/ope...megasst-2.html