Rigid sphere falling through air. Dynamic mesh
 

Hi there

I'm trying to set up a problem in fluent.
I'd like to simulate a rigid sphere falling through air at standard conditions accelerated by gravity onely using a dynamic mesh and UDFs.
right now my problem is, that fluent can't read my mesh. I always get the same Error warning:

WARNING: cell 2 of thread 15 has NULL face pointer 3
ERROR: Build Grid: Aborted due to critical error.

Here is the mesh I wanted to use:

http://www.pictureupload.de/original...1738_Mesh1.jpg

There is a region around the Sphere I have declared as new volume part when I have created the prism Layers. The reason for this is, that I want to move the boundary Layer and the Sphere in my simulation.

I have checked what happens, when I try to read in the same mesh in fluent, whiteout declaring the boundary Layer as new volume part. If i do so, there is no ERROR Warning.

For this reason I know, that there is something wrong whit this volume part declaration. but right now I can't think of any other possibility to realize my simulation.

Does anybody know what's wrong?


the Fluent User Manual says:

"If you create a single grid with multiple cell zones, you must be sure that each cell zone has a distinct face zone on the sliding boundary. The face zones for two adjacent cell zones will have the same position and shape, but one will correspond to one cell zone and one to the other."

I think that' why this ERROR occurs. But I don't understand how to realize this in ICEM?

Is there any other possibility to realize this Problem in Fluent? :confused:

thank you so much for your support.
Alex