I am solving the problem about natural convection. I have set that there is the buoyancy effect when I define fluid model. I choose 'Air Ideal Gas' as the domain fluid. When I tried to modify some property of the template fluid, I found that in 'buoyancy property' of ideal gas the thermal expansivity is not specify explicitly. I would like to know that if I choose template 'Air Ideal Gas' as the domain fluid, and CFX have to use thermal expansivity in computation, what value of thermal expansivity will be used? Thank you.

Atit

When using an ideal gas, the full buoyancy model is automatically set. Thermal expansivity is used only for the Boussinesq buoyancy model.