High depression at low alpha inlet (interFoam)
 

Hi all. I'm modeling a two inlet, one outlet device. It's like a vertical tube with a big principal (upper) inlet and a small (bottom) outlet. There is a secondary inlet.
At first time both inlets are set as fixedValue in velocity and zeroGradient in pressure, outlet is fixed value in pressure and zero gradient in velocity. Walls, as usual, are set fixedValue in velocity (0 0 0) and zeroGradient in pressure. Volume fraction is set 1 in inlets and zeroGradient in walls and outlets, it implies in this case that the system is working completely with water.
Problem arises when I set alpha < 1 in the secondary inlet, pressure near this inlets starts to go down, the lower alpha is, the lower pressure is. Secondary phase is air. Will there be any problem with excessive rho/mu ratio? How I can manage this problem in this case? May be BC at secondary inlet are wrong? I solved this problem Fluent without special care.

All answers all welcome... Regards.