[sharonyue]

Hi guys!

In the original dambreak case, alpha's outlet boundary is set as:

atmosphere
    {
        type            inletOutlet;
        inletValue      uniform 0;
        value           uniform 0;
    }

I think that means water and air can get out but only air can get in. Then I revise it into:

atmosphere
    {
        type            outletInlet;
        outletValue      uniform 0;
        value           uniform 0;
    }

and make there is more water in the fields by :

defaultFieldValues
(
    volScalarFieldValue alpha.water 0
);

regions
(
    boxToCell
    {
        box (0 0 -1) (0.3 0.5 1);
        fieldValues
        (
            volScalarFieldValue alpha.water 1
        );
    }
);

Then I run interFoam in OpenFOAM 2.2.x and 2.3.0. I can see that alpha is unbounded:

2.3.0

Courant Number mean: 0.032188 max: 0.996634
Interface Courant Number mean: 0.000976763 max: 0.220003
deltaT = 7.3338e-05
Time = 0.886652

smoothSolver:  Solving for alpha.water, Initial residual = 0.0004712, Final residual = 4.5912e-09, No Iterations 1
Phase-1 volume fraction = 0.459894  Min(alpha1) = -3.87751e-11  Max(alpha1) = 143.031
MULES: Correcting alpha.water
MULES: Correcting alpha.water
Phase-1 volume fraction = 0.459894  Min(alpha1) = -8.17479e-08  Max(alpha1) = 142.755
DICPCG:  Solving for p_rgh, Initial residual = 0.000217595, Final residual = 7.50267e-06, No Iterations 2
time step continuity errors : sum local = 1.21984e-07, global = 6.70143e-09, cumulative = -0.000355408
DICPCG:  Solving for p_rgh, Initial residual = 1.75272e-05, Final residual = 8.56153e-07, No Iterations 5
time step continuity errors : sum local = 1.39203e-08, global = -6.03115e-10, cumulative = -0.000355409
DICPCG:  Solving for p_rgh, Initial residual = 5.98614e-06, Final residual = 9.99259e-08, No Iterations 22
time step continuity errors : sum local = 1.6247e-09, global = -1.64737e-10, cumulative = -0.000355409
ExecutionTime = 63.87 s  ClockTime = 64 s

2.2.x is the same.


So we can see that when the water is getting out, alpha tends to be unbounded.

My aim is keep water in this field so I modify alpha's boundary. So what should I do?

Thanks in advance