I would like to take a simulation about an enclosure with natrual convection at high altitude, but get confused about the flow simulation setting. should I just change the gravity and pressure at General settings? or I need to build a new flow material which represents the air at high altitude. PS: I got some reference from Flothermo. such software allows user to set more paraments, such as density, expansivity. but I can not find the similar setting in flow simulation.