I got my solid floor modeling to work, and am moving on to a slotted floor scenario:
There is a slotted floor that separates a pit (below) from a barn (above). The airspace in the pit has an initial concentration of H2S = 156.9 ppm (the rest is air), and the airspace in the barn is 1,000,000 ppm air. I tried setting up the model (attached) with a fluid subdomain for the pit, but Solidworks doesn't like the situation where there is no solid divider above. Does anyone know how I can get this to work? I'm trying to get the simulation to run with natural recirculation. The velocity vectors seem to do this, but the gas evacuation/mixing is too fast if the initial concentrations are wrong.