Mixing Plane
 

I am using Mixing Plane model. It diverges on first iteration. I already lowered under-relaxation to 0.01.

I suspect that divergence may be caused by misalignment of mixing plane. Mixing plane was aligned neither axial direction or radial direction but with angle. I used axial direction for mixing plane.

Who knows if this can cause divergence? Or what can cause divergence? Thanks~!