/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011 OpenFOAM Foundation
     \\/     M anipulation  |
-------------------------------------------------------------------------------
License
    This file is part of OpenFOAM.

    OpenFOAM is free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    for more details.

    You should have received a copy of the GNU General Public License
    along with OpenFOAM.  If not, see <http://www.gnu.org/licenses/>.

Application
    interFoam

Description
    Solver for 2 incompressible, isothermal immiscible fluids using a VOF
    (volume of fluid) phase-fraction based interface capturing approach.

    The momentum and other fluid properties are of the "mixture" and a single
    momentum equation is solved.

    Turbulence modelling is generic, i.e. laminar, RAS or LES may be selected.

    For a two-fluid approach see twoPhaseEulerFoam.

\*---------------------------------------------------------------------------*/

#include "fvCFD.H"
#include "MULES.H"
#include "subCycle.H"
#include "interfaceProperties.H"
#include "twoPhaseMixture.H"
#include "turbulenceModel.H"
#include "interpolationTable.H"
#include "pimpleControl.H"


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

int main(int argc, char *argv[])
{

    // VVPF b:
    const dimensionedScalar gunits("gunits", dimensionSet(0,1,-2,0,0,0,0), 9.81);
    const dimensionedScalar gunits2("gunits", dimensionSet(0,1,-2,0,0,0,0), 1.5);
    
    #include "setRootCase.H"
    #include "createTime.H"
    #include "createMesh.H"

    pimpleControl pimple(mesh);

    #include "initContinuityErrs.H"
    #include "createFields.H"
    #include "readTimeControls.H"
    #include "correctPhi.H"
    #include "CourantNo.H"
    #include "setInitialDeltaT.H"


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

    Info<< "\nStarting time loop\n" << endl;

    while (runTime.run())
    {
        #include "readTimeControls.H"
        #include "CourantNo.H"
        #include "alphaCourantNo.H"
        #include "setDeltaT.H"
        
        runTime++;

        Info<< "Time = " << runTime.timeName() << nl << endl;
        //---------------------------
        

        
        
        //simplest possible solution
        //just check whether the center of gravity of the droplet is in the left or rigth half of the channel,
        //assuming the mesh is set up so that the center of origin of the x-axis is in the middle of the channel
        double alphaSum = 0;
        forAll(mesh.cells(),i)  //forAll(mesh.C(),i)    works as well
        {
           double currentPosition = mesh.C()[i][0];
           if (currentPosition < 0.)
           {
             alphaSum -= alpha1[i];  //*mesh.V()[i];  multiplication with cell voulme only necessary for non-uniform mesh
           }
           else if (currentPosition > 0.)
           {
             alphaSum += alpha1[i];
           }
        }
        Info << "\nalphaSum: " << alphaSum << "\n";
        
        

        if (alphaSum < 0.)
        {
          g=gunits*vector(0,-1,0) + gunits2*vector(1,0,0);
        }
        else if (alphaSum > 0.)
        {
          g=gunits*vector(0,-1,0) + gunits2*vector(-1,0,0);
        }
        else
        {
          g=gunits*vector(0,-1,0);
        }

        // VVPF c:
        Info << " AnalyzeGravity "
             << " " << g.component(vector::X).value()
             << " " << g.component(vector::Y).value()
             << " " << g.component(vector::Z).value()
             << endl;
        
        


        // VVPF d:
        // Comes from the file "createFields.H". You dont have to delete the lines 
        // in "createFields.H". The field gh is just initilaized there.
        Info<< "Calculating field g.h\n" << endl;
        volScalarField gh("gh", g & mesh.C());
        surfaceScalarField ghf("ghf", g & mesh.Cf());

        //---------------------------
        twoPhaseProperties.correct();

        #include "alphaEqnSubCycle.H"

        // --- Pressure-velocity PIMPLE corrector loop
        while (pimple.loop())
        {
            #include "UEqn.H"

            // --- Pressure corrector loop
            while (pimple.correct())
            {
                #include "pEqn.H"
            }

            if (pimple.turbCorr())
            {
                turbulence->correct();
            }
        }

        runTime.write();

        Info<< "ExecutionTime = " << runTime.elapsedCpuTime() << " s"
            << "  ClockTime = " << runTime.elapsedClockTime() << " s"
            << nl << endl;
    }

    Info<< "End\n" << endl;

    return 0;
}


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