Inlet boundary condition definition for quiescent air flow
My geometry consists of a porous zone region (R=2m) that pulls air from a R=25m hemispherical inlet plenum and exhausts through a pipe originating from the center of the pile. Source terms are applied in the fan subvolume to achieve the desired flow rate. Gravity is turned on since I will eventually replace the porous region with a DEM packed bed geometry.
I want to simulate the inlet plenum with quiescent air and believe a total pressure inlet boundary condition is the correct choice; however, I am uncertain if I should specify total pressure as constant 0 Pa(g) or -gravity*density*y. Both options give something similar to the shown vector plot that has the bulk of the streamlines hitting the pile originating from the top of the hemisphere.
My expectation is that the stream function in the plenum should be characteristic of a line sink (psi = m*theta) and therefore am suspicious of the inlet boundary condition definition. Thoughts?