Hi @jbergmeier,
Understood. I am however, woefully unfamiliar with this type of simulation case. Upon going through some sources, it seems implementation is not that simple. I will link the resources below that may help you. They go into detail about OpenFOAM and may be slightly different than what you see in SimScale, but SimScale is using OpenFOAM so the implementation should be identical.
From what I’ve read, it seems like implementation requires the use of AMI and coupled with the periodic BC. Along with that, you will need to define a mean velocity through the mesh and a pressure to reference from.
Otherwise, I will call on @jousefm & @1318980 who may have some idea on how to do this.
Cheers.
Regards,
Barry