Hello,

I am running a simulation with buoyancy on a very large scale (4000m high domain). I originally modeled air with Boussinesq approximation but I don't want the constant density. Therefore, I would like to model air as an ideal gas. Unfortunately, whenever I try this the air doesn't work properly and just falls. I tried to set up a pressure outlet at the top of the domain with the gauge pressure set to the drop in pressure at that altitude. This did not work. I even tried setting the drop in pressure to be twice as extreme with no luck. I set the operating pressure and reference density to what I expect the mean values to be (based on the height of the domain). I am using PRESTO! to solve pressure.

Nothing I have tried seems to work. The exact same setup worked perfectly with the Boussinesq approximation. Any help would be appreciated.