[mortezahdr]

Hello,

I have a 3D domain initially filled with air. Based on the figure below, water is injected with a certain velocity from top left to the domain and moves through the domain. I am using interFoam. The figure shows iso-surface of alpha.water = 0.5. The boundary specified is atmosphere. The water is being accumulated after hitting that boundary.

My question is, what kind of boundary condition for p_rgh, U, and alpha.water should I use, so that the water leaves the domain instead of being accumulated after hitting the atmosphere boundary. Currently, these BCs are as follows:

U:
inlet
{
type flowRateInletVelocity;
volumetricFlowRate constant 7.22E-06;
}

atm
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
_______________________________________
p_rgh:

inlet
{
type fixedFluxPressure;
value uniform 0;
}

atm
{
type totalPressure;
p0 uniform 0;
}
_______________________________________
alpha.water:
inlet
{
type fixedValue;
value uniform 1;
}

atm
{
type inletOutlet;
inletValue uniform 0;
value uniform 0;
}
_______________________________________
Thank you.

[mortezahdr]

Answer to my question: On the specified boundary,

U:
type inletOutlet;
inletValue $internalField;
value $internalField;

p:
type fixedFluxPressure;
value uniform 0;

alpha.water:
type zeroGradient;

I would like to thank you all for sharing your thoughts on this!!