Hello, I think I discovered the reason for the stretching but I'm still looking for a solution:
I just have one interior-face for the mesh. The area above and below the cylinder is just one zone in my case. I think the cell-row above and below the cylinder is one row, instead of two. If the cylinder moves downwards and the cell-row below collapses (due to the collapsing factors), the cell-row above the cylinder collapses also. Thats why it seams like a "stretching-process". If I try to separate the cell zones in Ansys fluent, the two "not-touching" cylinder lines also separate. After that I cant combine them anymore, because they dont touch each other.
Do you know how I can separate the cell zone in two cell zones (one above, one below) in the mesher, bevor I start to configurate the set-up?
Thanks!