Hi @nludwig:
Your last run (12) in Knipex Flow /…/ is based on that TET mesh:
I wonder on which premises you conclude, that you did everything but it does not work.
Please read that thread about ‘Urban Wind’ posted in 2022: https://www.simscale.com/forum/t/simulation-failed-urban-wind/95267/2
Mind as well, that ‘sky’ over your boxes is not the same (wall) as the ground.
Take care,
Retsam