[uncle_salty]

Hi,
I am having trouble with a natural convection problem in which there is a large temperature difference. The temperature difference is so large that the boussinesq model is not valid. when i turn on gravity and use a temperature dependent density function, FLUENT responds with a floating point error because my solution is diverging.

does anyone know how to fix this?

if it helps, here is a description of the system...
a vertical rectangular cavity filled with air where one wall is radiating a 5kW/m2 heat flux. I want to find the velocity of the air at the top and bottom of the cavity, as well as the temperature difference in the air.

thanks for any help in advance.