[JuliaFed]

Hi everybody, I am running a multiphase (water+air) simulation using twoPhaseEulerFoam and my problem is that air rises too quickly and accumulates at the top of the domain (a wall). This doesn't happen when I use a similar setup using interFoam or Ansys Fluent.

Problem setup:
- geometry: a horizontal rectangular channel (3D). A thin porous region is defined at the bottom of the channel.
- inlet (left): water flows in with a fixed velocity
- second inlet, inlet_o2 (bottom): air is injected upwards with a fixed velocity
- outlet (right): for both phases
- everywhere else: wall

setup_twoPhaseEulerFoam.jpg


My goal is to simulate air rising through the porous medium and being carried by the horizontal water flow. My issue is that air rapidly rises straight up through the porous layer and the channel, accumulating at the top wall of the channel. I started from the bubbleColumn tutorial (actually, this modified version: https://www.cemf.ir/simulating-a-bub...sing-openfoam/)
I am using most of the original boundary conditions, except that gravity is in the z direction and I modified the bottom boundary to be an inlet for air.
twoPhase_BC.png

I also attach some screenshots of alpha.air the illustrate the problem.
alphaair.jpg

Any guidance or suggestions would be greatly appreciated, I'm happy to share specific input files or parameters.