[Ricardo_13]

I tried setting up a "simple" buoyancy driven flow problem by simulating the draft through a smoke stack purely as a function of the buoyancy potential.

I would like inputs on my approach.

I am typically considering a vertical pipe (6m) with pressure inlet and outlet (both set at 0Pa g) as my 2 boundary conditions. The pressure inlet is set at 400deg C which fixes the inlet density. The stack wall is adiabatic for now. Density based solver, running steady state with an ideal gas (air) activated.

I am struggling to understand how the specified operating density, which is currently set as 1.225 kg/m3 influences the result. Some literature states that the value is used to stabilize the buoyancy force in low mach number flows, other suggests setting this value to 0, which results in convergence issues, while other states it to be the free stream density.

Any clarity on the specified operating density and my approach in general will be appreciated.

Regards