[cfd_user_pune]

Hi Everyone!

I am simulating cooling of a component by natural convection. The component is placed in rectangular box at middle location with rectangular big box inlet at bottom and outlet at top.

What should be density selections in create/edit material tab (ideal gas or Boussinesq)? Why operating density should be zero in case of ideal gas?

I run simulation for above two types of air density keeping gravity y=-9.81m/s (inlet is at y=0, outlet is at y>0)
For density as ideal gas , flow of air is downward (towards inlet)
For density as Boussinesq, flow of air is upward (towards outlet)
Avg velocity at inlet or outlet for ideal gas density is 1.5m/s and that of Boussinesq density its 0.3m/s (which seems okay for natural convection)

Can anyone please explain why there is difference in direction of velocity flow by just varying density of air in material tab?

Thank you in advance.