problem with Mesh motion, please help me!

Giuliano

Hi everybody, I'm trying to simulate the interaction rotor-stator of a centrifugal compressor: - I'm using just one channel with a central blade, I have a rotational periodicity of 15°; - For the rotor fluid the input is Mesh motion with a certain angular velocity. When I start a mesh motion to verify the sliding rotor-stator, I see that at the end of the period the rotor doesn't come back to the original position (rotor- stator alined), but starts from a period before so that it needs another period to come back to the original position. I launched a simulation but as I expected I had a periodicity double than the original. Anyone knows the problem? Please help me.