[Felix_Sp]

Hey everyone,

I just wanted to ask what roughness is applied to the wall functions of an added solid. If I want to use separate roughness coefficients on different boundaries what roughness is chosen for the solid.

If I for example use:

B 52 0.01
B 53 0.05
B 55 0.001

in a rectangular flume and have a solid object in the middle of a rectangular channel which roughness will be applied? How is this determined? Is there roughness at all on solid objects? Is the roughness on a solid object set to the global roughness, while the boundary roughness can be overwritten?

Many thanks in advance!

[valgrinda]

Hi Felix,

right now, solids use the B 50. To be able to assign different roughnesses on different solids is on my todo-list

[Felix_Sp]

Thanks for the quick reply!


Does that mean that I can set a roughness to all solids with B 50 and different roughness coefficients to the boundaries (e.g. with B 52 and B53)? Or are they being overwritten by B 50?

[kamath]

You are correct.
B 50 is the global wall roughness and will be applied everywhere in the domain.

B 51-54 will overwrite that, but only for the specific wall that the option refers to.

So, in that way, yes, you will be able to set different roughness for the solids and the boundaries

[Felix_Sp]

Thanks for the clarification!