[A_Pete]

Having problems with snappyHexMesh and rotating motions using AMIs. I have a case with a propeller, which is rotating inside of that AMI. What I am having trouble with is the interfaces and the minimum weights for the interpolation between them.

I made one mesh, which is running very good and the minimum weights for both interfaces are around 0.5 after a whole rotation. Most of the time the minimum is somewhere at 0.7-0.8. This mesh has 77712 faces on each interface. What I want to do now is to refine just the propeller surface. So I change exactly one parameter in my snappyHexMesh dict, to define a higher maximum level of refinement of my propeller surface. This results in a mesh, which of course has a lot more cells, but leaves the AMI (as before!) with 77712 faces. This makes me think, that my refinement didn't really effect the AMI And if it did change the faces of the AMI, it should be so little, that it doesn't make much of a difference for the rotation. But this is not the case. The refined mesh does not run, because after like 50 time steps there appear lots of "0" minimum weights on the interfaces.

To sum up:
Mesh 1: propeller in AMIs, which each have 77712 faces
Mesh 2: same as mesh 1, but with refined propeller; also 77712 faces on each interface

Does somebody have an idea, what I can do to get my refined mesh running? Do you think the interfaces are the same? Because I can't see a difference. It seems like I can't get my finer mesh running whatever I do. I tried to put single prism layers on the interfaces with an expansion ratio of 1, but that doesn't help either in that specific case.