Rotating coaxial cylinders

Xiana

Hi, I am simulation the flow between 2 rotating coaxial cylinders with radius of 0,25 and 0,20 m. I´ve defined my inlet, a ring at the bottom of the anular space, like a velocity inlet with 1m/s in axial direction, and the outlet, a ring at the top, like a pressure outlet. The fluid is a reference frame which rotates at 1000rpm. I´ve used the Reynolds Stress Model to model the trubulence but i still have a lot of problems to get a converged solution. The residuals remain hihg and with oscillations, specially the continuity, because ich have a lot of reversed flow and the balance of mass flow doesn´t agree. Can anyone help me?!

Thank you