I have two tubes, the smaller one is inside the bigger one, allowing heat transfer. My problem is the mesh. As I have two tubes, what should I do? - split the bigger tube using the smaller one; - split the bigger one using the smaller one, but keeping the original smaller; - don`t split anything, just stabilish the boundary conditions. I`ve experienced problems with all the options, so I`d like to know what is the better?

Hi,

I would try splitting the larger tube with the small tube (dont retain the samller tube). You should be able to mesh both sections and both tubes will be connected. You must define the face of the smaller tube as a wall though. When you import into Fluent, it will automatically split this face into two coupled walls. This is normal and it will allow you to specify conditons on both sides of the wall. In fluent you will also be able to specify wall thickness etc.

Good Luck.