Moving part in a fluid

E. BOINOT

Hi everybody

I'm trying to model a moving solid part (translation) in a fluid (a resin).

Can I simply apply a boundary condition to this part, i.e. a translational velocity? The problem is that it doesn't converge easily (even with decreasing the under-relaxation factors) Moreover, when the blade move (unsteady), the gap from the previous time step remains "black" in the graphics window, so I can't see the velocity in the gap

Shall I use another model? (sliding mesh, for example?)

Thanks a lot