natural convection with COMSOL 3.2b

sam

Hi,

I use COMSOL to modelise a roof and I want see the natural convection to do that I do 2 tests in transient mode:

- one with the general heat transfer module and the incompressible navier stockes module. It doesn't finish because it do an error with the damping factor.

- one with the general heat transfert module and the non-isothermal flow. It doesn't calculate good answer.

If someone can help me to do a good calculus or an idea for an other software.