[william.z]

Hi guys,

Just an operational question about Star ccm+. I'm trying to perform an unsteady simulation of a simple heat exchange case of a rotating object, using the overset mesh.
The case is very simple:
1) a background air region shaped as a simple cube.
2) an overset region, also shaped as a cube (way smaller than the background region)
3) the effective shape of the object that rotates that is an even smaller cube.

I successfully made the attempt in performing an unsteady simulation with the cube in motion. Just took the background region and the overset region (the second one subtracted by the cube shape and put in motion).

I'm now having real trouble in adding the heat exchange. I want just one of the faces of the cube to have a fixed heat flux, that will transfer heat to both the cube it self (solid) and the sorrounded area.

For this porpouse I thought I needed to add the solid cube region (also to be put in motion) and then create interfaces between the cube and the cube shape subtracted to the overset mesh. One interface rappresenting one face of the cube with a fixed heat flux and the other 5 faces rappresented by a conjugated-heat transfer interfaces.

The problem is that now that, when I try to add interfaces, I'm no more able to mesh. Everything I try says to me either that "some volumes are not included" or that "regions are self intersected".

Hope it's not too much of a basic question, but i didn't find anything on literature.

[JB1989]

When you want to use overset mesh you should not subtract the cube from the background. Simply create two meshes, without subracting anything, then mark both boundaries (of the background and overset) and select create interface -> overset mesh.

[william.z]

totally agree with you, the only reason why i didn't do that is because if I don't perform a subtract I don't have common surfaces between the two regions (air and solid) through which specify the heat passage. Or am I losing something?