Cfx
 

Hi.
I want to simulate a marine propeller in cfx.
I have heard there are three ways to do.
First one:
using of one cylinderical domain that is constant and the propeller is rotating.

Second:
two cylinderical domain that the smaller one is rotating and the bigger is constant.

Third :
the propeller is constant and one cylinder is rotating.
Am i right?

I do not understand what you are proposing. If you are modelling a spinning propeller then you need to spin it somehow. The easiest way to do this is with a rotation frame of reference, so the propeller needs to be in a rotating frame of reference. The only choice is whether you have a stationary frame of reference around it, which you would use to model things which are not rotating like the ship hull or free surface.