Multiple Sahdows / Periodicity Problem
 

Hello everybody!

I have the following problem:

My grid is a rectangulaire box in 3d, the side surfaces being 8x8 meters, and the depth of the box being 36mm.

Inside the box, there are different regions (structured and unstructures mesh), which are connected by interfaces (no shadows, because the mesh on the interface consists of quads on one side and of tris on the other side of the interface surface).

These interfaces are perpendicular surfaces to the side surfaces (the side surfaces are the 8x8 meter surfaces who define the sides of the box).

My problem:

I would like to define the side surfaces as periodic boundaries. I can do this, the creation of the periodicity works fine.

But when I try to create Grid-Interfaces (in the "define/grid Interfaces"-menu), fluent shows a message: "thread xy has multiple shadows". I identified thread xy as the zone which has been defined as periodic (the side surface).

I have tried the "repair-periodic"-function, it didn't help.

Definig the same surfaces as interfaces without having defined the side surfaces as periodic, works fine.

So there seems to be a problem with the definition of interfaces, who have periodic surfaces perpendicular to them.

Any suggestions, tips or help?

Thanks, Michael