I have a case that there is a velocity inlet and one pressure outlet. The rest of my domain boundaries are walls. Nevertheless i have a small opening that i don't know how to model it. I know from my experimental data the pressure just after this opening. My flow is 2-phase (gas and solids Euler-Euler). From this opening gas should enter my domain and solids should be exiting.

Please help!!!

would you explain ur problem more clear? I have no idea what u wanna do

Thanks for your reply. I'm modelling a CFB. I have two euler phases, gas and solid. They are entering in the CFB through two different inlets. I modeled those boundaries as velocity inlets. Nevertheless, there are two outlets in my CFB. In the first both solids and gas should exiting my domain. I modelled this boundary as pressure outlet. My case just with one inlet and one outlet converges. But the second outlet is tricky. In this boundary solids should escape from the CFB and gas should enter. Unfortunately i don't know the mass fluxes. I only know the pressure there. I tried to model this outlet as pressure outlet. I set the pressure there as my experimental data imply and i was expecting that there will be a backflow for gas. This configuration did't work well. There was no backflow and the solids mass flux was too big! Any suggestions?