Rotor not converging
 

I have a ten bladed rotor that I am simulating. I have created a grid for 1/10th of the rotor (i.e. one blade). The sides have a periodic boundary condition, the inlet is a pressure inlet, the outlet is a pressure outlet, and the outside part of the "pie slice" has also been set to pressure outlet. The rotor is rotating at 2800rpm with 25m/s inflow. I am running a 2nd order accurate compressible unsteady model and my residuals will not converge more than 1e-2. The forces on the rotor are relatively stable they vary slightly from time step to time step.