is your rotating part basically a plate with fins on it?
does it act like a pelton wheel where the flow acts on the rotating component to spin it?
what direction do you expect the flow to go in?
something i might recommend doing here is adding the flow velocity vectors onto your cut plot to see exactly what is happening (what direction the flow is going).
then create another plot where you set the max to something lower than 16. maybe the flow in the center is actually low.
with this all being said, i'd check the technical reference and solving engineering problems document. i think this is at the barrier of what flow simulation can do. it really is meant for flow to come in from the side and leave out the middle. something like a pelton wheel like you have is slightly out of the scope of what the method can do.