[Whyman]

Hi everybody!

I have a big doubt about the behaviour of OpenFoam with calculation in presence of the gravity value.

I tried to simulate a cube, partially filled with a liquid (for example water) and initially quiet: so two phases are present in the domain. I also simulated the cube as wall, so that the liquid cannot escape from the domain.

When i simulate the gravity imposition in whatever direction (in my example the direction was the X-axis and the value was 9,81), the liquid begins to move following the direction of the gravity vector.

The problem is that during the calculation, the liquid volume begins to decrease.
This is impossible because the cube is a closed wall and the liquid cannot escape. On the contrary, the result after 10 second is the attached picture.

The solver that i have used is interFoam and the model is laminar.

The boundary conditions are the following:

Velocity:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
location "0";
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
parete
{
type fixedValue;
value uniform (0 0 0);
}
}


// ************************************************** *********************** //

Pressure:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [1 -1 -2 0 0 0 0];

internalField uniform 100000;

boundaryField
{
parete
{
type zeroGradient;
}
}

// ************************************************** *********************** //


Alpha:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: http://www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object alpha;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 0 0 0 0 0 0];

internalField uniform 0;

boundaryField
{
parete
{
type constantAlphaContactAngle;
theta0 5;
value uniform 0;
}

}

// ************************************************** *********************** //




What is the problem? Can someone help me?

Thank you

Regards