Reply To: Calculation diverges when mesh is refined

[Manish Patel]

Okay, so I have found out the problem. The Ansys fluent automatically splits the interior into two parts: 1. interior-part-surface-body 2. part-surface-body. 
So, I used combine > merge zones tool to merge those two. 

So, when I run simulation without merging those two zones, the simulation runs smoothly. 

When I merge those two zones, the simulation diverges. 

Wihout merging, the mesh looks weird as some cells are missing from interior. 

Comparision of the with merging and without merging looks like this:

What should I do now?