Variable wall roughness
 

Hello!

I want to set a variable roughness on the lower wall of a BFC domain, depending on the depth (height of the domain) which varies. Is the following possible:

PATCH(name,LOW,1,NX,1,NY,1,1,1,LSTEP) SPEDAT(SET,ROUGHNESS,name,R,GRND)

with appropriate coding in GROUND to check the depth of each bottom cell? If so, where in GROUND?

WALLA seems to be out of the question, as it is a constant for the entire domain. There is supposed to be a patch-wise variable called PVROGH to be used for setting the roughness on an individual cell basis, but I am unsure exactly how this should be done.

Grateful for help or hints,

Olof