we had a discussion today in the CFD team in our department and I mentioned that it is usually not
necessary to require a user to define boundary conditions for turbulence quantities on or in the vicinity of walls.
Usually, wall velocity and heat flux and/or temperature are sufficient.
Physical considerations or model equations require a certain value or asymptotic behavior of turbulence quantities such as turbulent kinetic energy, turbulent frequency or dissipation at or close to the wall. Therefore, you can either implement a fixed value on the wall (such as turbulent kinetic energy = 0) or set a solution dependent value in the cell center of a wall-bounded cell (which requires that you can identify these cells) and adjust the contributions of these faces or volumes to the matrix coefficients directly.
At least, that is how I remember we did it in our code at university.
In OpenFOAM® you can or have to define wall values, and correctly setting k=0 does not even work.
Any comments? Maybe this has already been discussed on www.cfd-online.com
. I posted this thread there also today.
Best regards, Ulf.