pressure outlet BC for Boussinesq with Fluent

stephane

Hi,

I'm trying to solve a time dependent problem with Fluent using the boussinesq approximation. I have a velocity inlet and a pressure outlet (outflow is not good if the density is not constant). if I keep a constant gauge pressure at the outlet, after a certain time a gradient of pressure appears at the outlet creating a high velocity and there is divergence. I ve written an udf with a linear profile of pressure as well and used it at the outlet BC but it doesnt work either. So i'm wondering about the settings at the outlet.

thanks in advance, stéphane