[GardenLake]

Hello everyone,

I am having an issue with the interfoam solver. I have a water flowing through the model with an inlet and outlet. I also have air on top of the water. When I have flow=0, I have no issue running. When I start flow (specifying an inlet velocity), I have an issue where my max alpha in MULES goes above 1 (which shouldn't happen, and my pressure goes crazy.

Has anyone had a similar issue and had a fix? I think it may have to do with the interface between the phases (air and water) changing but am unsure.

Thank you for your help!

[2538sukham]

Any chance of sharing the case or sharing the U p_rgh (or pd )?

[GardenLake]

Hello,

So I was able to fix the problem, I had forgot to designate a boundary and it was "default face".

Now I am having issues with my alpha value gets very high and low (2*10^18 and -2*10^18) and then crashing. In addition, I have a "wall" with a zero gradient designation getting alpha values below 1 but this is before crash (it is under water by quite a ways, should not be getting anything below 1). I would post a screenshot but can not figure out how to do that, it says I keep getting denied.

Does this problem ring a bell to anyone?

I have one inlet, an outlet, a wall, and an atmospheric top.
Alpha BC's

Inlet:type fixedValue;
value uniform 1;
Outlet: zeroGradient
Wall:zeroGradient
Atmospheric Top: type inletOutlet;
inletValue uniform 0;
value uniform 0;

Do these boundary conditions seem reasonable?

[GardenLake]

It is supposed to be open channel flow.
My U boundary conditions are...

wall: fixed value uniform (0 0 0)
inlet: fixed value uniform (1 0 0)
outlet: zeroGradient
Top: pressureInletOutletVelocity uniform (0 0 0)

My P boundary conditions are...
wall: fixedFluxPressure
inlet: fixedFluxPressure
outlet: fixedFluxPressure
Top: total pressure uniform 0;


Could the issue be with one of these?

[2538sukham]

For the pressure in outlet, try the zeroGradient bc. Other bc's look fine.
With regards

[GardenLake]

Hello,

Thank you for the response!

I tried the zeroGradient but now I am getting pressure GAMG value to crash. My alpha values at the crash are still quite large (+- 10^9). My crash occurs after about 0.4 seconds of runtime.

Do you have any other suggestions on what may be the issue? I tried "check mesh" and it came back with everything being ok

[2538sukham]

Can you share the case here. I would like to run and check it. I am not an expert but maybe I can look at the case and report it to you.
With regards. (Share zip file). I would put zeroGradient for the inlet as well for pressure.

[GardenLake]

Does anyone have an idea on what my pressure boundary condition should be for a boundary that is immediately above the inlet (which has wetting fluid going through it at a specified velocity), and is just exposed to what should be a normal atmosphere?