[sacrover]

Hi,

I'll first explain the setup. There are two cylindrical cell zones. The inner cell zone has a propeller in it. The analysis is steady state and and I'm using the MRF approach to feed in the angular velocity of the propeller.

Case 1: Dynamic case
By dynamic case, I mean that the propeller is moving forward with some velocity (in other words, at some advance ratio > 0). The boundary conditions for this case is well defined (velocity inlet and pressure outlet). The solution converges and the flow field variables are as expected.

Case 2: Static Case

The same setup but with zero (or close to zero, say 0.1 m/s) inlet velocity. Now there's a problem. As we start approaching lower and lower inlet velocities there is a reversed flow observed at the outlet boundary. This, as of what I understand, triggers imbalance in the continuity after which, gradually, the solution diverges.

My questions:
a) What boundary conditions would properly define the Static case?
b) What would be the right way to initialise the solution?
c) Are there any alternative approaches to model this kind of problem?

Thanks alot.