Boundary condition : Interior
 

I have a cylindrical volume of water. I want to define a smaller cylinder (hypothetical) inside this volume just to define a higher thermal condition inside it uptil a certain time (eg. t=6000 secs) (By an UDF to define this smaller vol as an energy source. At t>6000 I want to stop this source and see the transient temperature profile.

For this I created the larger volume and then subtracted (and retained) the smaller one. I meshed these 2 volumes.

Please note that both the volumes are basically the same continuum, but with different thermal conditions. The faces for the smaller volume are therfore defined as interior.

I exported the mesh to FLUENT 5.3 But it gives error that the faces of the smaller volume cannot be changed to interior ( because there is only one adjacent cell zone).

But I carved the smaller vol out of the larger one. How come there is only one adjacent cell zone?

Re: Boundary condition : Interior
 

If you are using gambit, probably you have 2 coincident surfaces; if you can't delete one of these try with merge faces (virtual forced). Bye.

Re: Boundary condition : Interior
 

You may instead of subtracting want to split the big cylinder using the smaller cylinder as the split tool.

Re: Boundary condition : Interior
 

It worked. Thanks.