Hi Can anybody help me? i'am trying to simulate Air Flow between two independant rotating disks and i have a problem to define the boundary conditions (there is no inlet/outlet boundaries).The only condition i know is The static pressure (atmosphere 1.013e5 Pa) is present everywhere before the rotor disk starts. All ideas are welcome.

Regards

If the disks are perfectly circular and symmetric the easiest thing is to put a cylindrical coordinate system in the center of each disk and then use a moving wall boundary at each disk utilizing the coordinate systems just created. The walls will then be seen as rotating even if the actual mesh is fixed.