natural convection in attic spaces
 

Hi i am having a problem with modelling natural convection in an isosceles triangle heated from above and cooled from below. Grashof number ~ 2 x 10^9. At the moment i am having trouble getting convergence of my solution. i have used both laminar and turbulence models and have set the energy residual to 0.8 as recommended in the instructions. Does anybody have any idea on how Fluent can be used to model high grashof number natural convection? The instructions seem to suggest that Fluent has trouble modelling in this region

hello i'm a begineer user of Fluent I want know how to set Grashof number in Fluent ?? can u explain to me what shoud I do to have a Gr+2.5 E +7 if my Re =5000 and d=1 viscosity + 1/Re velocity inlet =1 ??