Hi.

So I've been working on a fan simulation on SIMULIA 2022 Fluid Scenario app using the MRF zone method. I've simulated several fans before, using that same method, but the only problem going on in this case is the fact that it has a bell mouth (shroud) around the fan.

The space between the fan and the bell mouth is extremely small (7 mm) which in turn affects the diameter of the MRF. The mesh is never resolved correctly no matter how much local mesh I refine in that zone. 

I have tried making the MRF zone bigger than the bellmouth itself, but the case is still diverging. And I'm not even sure if that is a correct approach since that I'm used to only having the rotating part inside the MRF, not stationary walls like the bellmouth.

Does anyone know another method that this can be resolved?