[thomas.]

Hello all,

I am dealing with a 3D turbulent incompressible (air with M<0.3) suction problem case and I am quite confused regarding the correct boundary conditions I should be using, since I am not getting the expected flow. Solver: simpleFoam.

I am still struggling with the p and U boundary conditions, so I haven´t implemented a turbulence model yet. I would be eventually using k-omega-SST with wall functions. My mesh has about y+ = 1, since I read that the k-omega-SST turbulence model with wall functions supports meshes with y+ < 30.

The geometry has 2 inlets and one outlet, being one inlet an atmosphere-connected patch ("atm"). The other inlet ("inlet") has a constant volumetric flow rate. The outlet ("outlet") has a fixed pressure value (negative).

So far I have used following boundary conditions for each patch:
"inlet":
U => flowRateInletVelocity
p => zeroGradient / pressureInletVelocity

"atm":
U => zeroGradient / pressureDirectedInletVelocity
p => fixedValue (0)

"outlet":
U => zeroGradient / pressureInletOutletVelocity
p => fixedValue (-800)

With these boundary conditions I am actually getting flow out of the "atm"-patch and it is supposed to be the opposite of that.

Help would really be appreciated.

Thank you very much in advance!

Bye,

Thomas