Hi Guys!! I´m trying to simualte a cylinder with another one inside, the big one contain air that will pass inside the smallest through a hole on the surface of the last one. I have created two solids, the smallest cylinder inside the big one (sub-domain and domain, respectly) but now I need to create a boundary condition on the surface of the sub-domain, what can I do?

Take care

Carola

for the wall of the inner cylinder it should be wall - thin surface bound. cond. (with all the surfaces exluding the - I guess trimmed - surface for the hole) and the (trimmed)surface of the hole should used for no kind of any boundary cond. . In this case this hole-surface will be a flow-through surface.

If I understood your problem...