[Jekke123456789]

interFoam - steady current: air in water


I am a searching for a solution of my problem, I am trying to check the velocities at a rock berm at the sea bottom for a steady current. Later one waves will be added but that are problems for later. I am using OpenFOAM v1812.

Specifics:

- current 0.49 m/s

- beach at the end


Main problems:
- air inside the water at the inlet.
- increase of water height in time (need to be constant)


The mesh is easy, with the use of stl file . It consist out of a berm and a beach at the end. See attachment.




These are some files that could be useful, if anything else is needed, let me know:
BlockMesh:


x-axis: 0 – 35

y-axis: 0.01 – 0.06

z-axis: 0 – 3

hex (0 1 2 3 4 5 6 7) (700 1 60) simpleGrading (1 1 1) //5cm fo each cell in x and z direction

Everything type: Patch, later on sides are set to empty

Set fields:



defaultFieldValues
(
    volScalarFieldValue alpha.water 0
    volVectorFieldValue U           (0. 0. 0.)
);

regions
(
    boxToCell
    {
        box (0 0.01 0) (35 0.06 0.750);
        fieldValues
        (
            volScalarFieldValue alpha.water 1
            volVectorFieldValue U           (0.49 0. 0.)
        );
    }
);



Boundary conditions:

alpha.water:
    inlet
    {
        type            zeroGradient;
    }

/*
    inlet // I tried this too, but then the whol inlet was water instead of only a height o 0.75
    {
        type            fixedValue; 
        value           uniform 1;
    }
*/

    outlet
    {
        type            zeroGradient;
    }

    ground
    {
        type            zeroGradient;
    }

    sides
    {
        type            empty;
    }

    top
    {
        type            inletOutlet;
        inletValue      uniform 0;
        value           uniform 0;

    }



U:



  inlet
    {
        type            fixedValue;
        value           uniform (0.49 0 0);
    }

    outlet
    {
        type            fixedValue;
        value           uniform (0. 0 0);
    }



    ground
    {
        type            fixedValue;
        value           uniform (0 0 0);
    }

    sides
    {
        type            empty;
    }


    top
    {
        type            pressureInletOutletVelocity;
        value           uniform (0 0 0);
    }

p_rgh:
inlet
    {
        type            fixedFluxPressure;
        value           uniform 0;
    }

    outlet
    {
        type            zeroGradient; 
       // value           uniform 0;
    }
    ground
    {
        type            fixedFluxPressure;
        value           uniform 0;
    }

    sides
    {
        type            empty;
    }


    top
    {
        type            totalPressure;
        p0              uniform 0;
    }



Results:

air at inlet See attachment

Rise of waterheight starting at the beach See attachment



So now the problems can be seen in the figures, I just want a steady state flow a the inlet, without air that is commin in to the water.

I tried it without the beach and have a uniform value of 0.49 at the outlet but still air is at the inlet.



Is there a way to set a boundary condtion only to the water part?



Any other suggestion is welcome for a steady state current with interFoam!?