There are 2 volume which are connected by one common sharing interface (face). The mesh around this single interface is non-conformal. During the computation, the turbulent viscosity reaches to its limit and then after some iteration the fluent stops. The problem causes no out flow from pressure outlet and the velocity remains zero at this face and everywhere. The cells with high turbulent visosity are located around the interface.

have you defined the couple of interfaces in fluent?(define/mesh interfaces)

if not, then a check mesh should failed

Yes, I have defined the interface and without definition, it would not be possible to initialize.

Are the meshes on both interfaces with the same order (size)?

No there is a difference in mesh size around interface. Because one volume is very smaller than the other.

It could be the reason, especially if the difference between cell's size is too high.

Thanks, I will try to reduce the mesh size. Anyway do you have any other comments?

without having the model, it's quite difficult to analyze your issue. If your still have troubles, you can post your *.cs file on a share server, I will take a look at it

It sounds like your volumes doesn't share data between the 2 volume meshes. For example, fluent sees your interface as a solid wall rather than an interface between two volumes. That's why you have zero outflow, and no convergence, the fluid can't leave the system. If the meshes are different sizes at the interface then this is likely. I've had the same problem before. I don't know how to fix it. I've asked around and haven't got any answers. It mostly happens to me when I do boolean operations on volumes.

Thanks

You are right about boolean operations on volumes. Because i used split function to connect these two volumes and keep the inteface which gives us an independent mesh strategy in both volumes. After merging two volumes (obvious that the inteface will be deleted), the model can be solved very easily without any error but i am not satisfied with mesh.