Separation

Atit

I use CFX 5.6 to solve one problem with bouyancy effect. The circulation is expected, then I use 'Mesh Control' for fine grid in the expected zone. After I got the converged solution. I used vector plot and found the circulation in that zone. Then I refine and expand the radius of that 'Mesh Control.' This time I got the overflow error. I try to use finer and expand the radius and then get the overflow error again and again and again. I suspect that there might be the seperation there. Can CFX deal with seperation automatically or do I have to set anything? and how do we check in CFX if there is the separation? Thank you very much.