Trouble with non-conformal grid interface
 

I have an impinging jet problem. I have two parts where one is a box shape and the other part is the round nozzle. I create the mesh separately.

The bottom surface of the box is set as a wall and the sides are pressure boundaries (open to atmosphere).

The top surface of the box is set as interface-1 boundary condition.

The bottom surface of the round nozzle is set as interface-2.

The sides of the nozzle are set as walls and the top surface as an inlet.

I use Tgrid to merge the two meshes.

I open the merged mesh file in Fluent6.0 (3D). I define the interface using grid interface and give it a name as inteface-1-2. Then two walls are created (say wall-15 and wall-16). wall-16 is the non over-lapping part of interface-1 and interface-2 which is exposed to the atmosphere. I reset the wall-16 boundary condition as pressure-inlet (to simulate entrainment boundaries).

Then when I run Fluent6, it gives the error

"Error: fluent.6.0.20 received a fatal signal (SEGMENTATION VIOLATION). Error Object: #f " .

I am unable to get rid of this error. This problem only runs when I set the wall-16 back to wall. Any other boundary condition does not work. If I set it to wall then my simulation is not right as the top surface is exposed and not covered. So I need a pressure boundary condition there.

Could someone tell me what the problem is and how I can bypass it ? Or is this a bug in Fluent6?

Do reply soon. Thanks a lot.

Anindya