Zero velocity of liquid at outlet in stratified flow using interFoam
 

Hi,

I am using interFoam to simulate a stratified flow. Although the geometry is relatively complex, it is qualitatively similar to channel flow; it is an enclosure with an inlet and an outlet.

I pretty much use the same boundary conditions as the waterChannel case, although without the "atmosphere" patch. At the inlet I use a fixed value for both, the velocity and alpha. The alpha corresponds to a stratified flow, with a very thin layer of liquid at the bottom of the inlet. I use different velocities for the two phases, with the velocity of the liquid being approximately an order of magnitude less than that of the gas. For the outlet I am using zero gradient for alpha.liquid and inletOutlet for U with (0 0 0) for the inletValue. To simplify the problem I am running the case as a laminar flow.

Everything seems to work fine up to the point where the liquid reaches the outlet, where the velocity of the liquid cells instantly switches to zero (i.e. inflow). All other cells (i.e. gas cells) seem fine.

Does anyone have a clue as to why this might be happening. Any help would be greatly appreciated.

Cheers
Mike