hi i got a problem. My domain is 2D-axisymetric rectangular domain 0.3x1.2metres to use a pressure-swirl injector model. I use inlet/outflow and axis and wall BC's. I set velocity = 0 since it is still air and initialize for turbulent flow since the dpm injection will cause some turbulence around the injection. Solution converges immediately since there is nothing to calculate for v=0. When I introduce the DPM by pressure swirl model with massf/r= 0.001kg/s (too high? this is data from experiments) the calculations is very unstable. I use two way coupling which, I am thinking causes the DPM momentum source terms to push the continuous phase along and cause reverse flow since there is no velocity inlet. I was wondering does anyone know how to get around this? Should I just solve it for unsteady? Or try different BC's? Or should I have velocity flow even though it doesn't make sense when I am comparing with spray into still air.

Thank you for ur time

use Pressure outlet in out flow use very very small velocity in initialization bye