Fluent Overset Mesh: Calculation happens only on the internal zone?
 

Hi everyone,

I am not new to Fluent, but I am new to overset meshing with Fluent. I set-up a very basic test case (I do not want convergence). A cube being the background mesh and a cube with a circular hole (BC as wall) as the internal mesh.

The two regions are set-up as two fluid zones: External and Internal.

Attached is an image of the solution, ignore the results, but why am I seeing a solution on the internal domain only? The inlet/outlet is on the external domain in blue and red on the screenshot. But the flow seems to be happening only on the internal domain. The overset meshing seems to be taking place fine, but why do I not have a solution on the entire domain?

I have a feeling I have set the boundary conditions wrong? So here are the details:

External volume:
Left is inlet
Right is outlet
Top and bottom symmetry

Internal domain:
External square as "overset"
Circle as wall

Am I setting the wrong boundary as overset? I think not. I looked at this video and everything seems the same other than the geometry https://www.youtube.com/watch?v=wN-VGAHdxX0