[kk415]

Dear Foamers,


I am trying to replicate the following work in OpenFoam.



https://gfs.sourceforge.net/examples...urbulence.html


https://gfs.sourceforge.net/examples...lence.gfs.html


Here is the piece of code I have added in interFoam as I want to study interaction of vortices and droplet in future.


Ueqn:

    label nCells = returnReduce(mesh.cells().size(), sumOp<label>());
    vector Ubar(gSum(U)/nCells);

        solve
        (
            UEqn
         ==
            fvc::reconstruct
            (
                (
//                    mixture.surfaceTensionForce()
            sigma*fvc::snGrad(alpha1)*fvc::interpolate(C)
                  - ghf*fvc::snGrad(rho)
                  - fvc::snGrad(p_rgh)
            + fvc::flux(1e-1*(1-alpha1)*rho*(U-(Ubar*dimChange2))*dimChange1)
//            + fvc::flux(1e-1*(1-alpha1)*rho*(U)*dimChange1)
                ) * mesh.magSf()
            )
        );

pEqn:

    surfaceScalarField phig
    (
        (
//          mixture.surfaceTensionForce()
      sigma*fvc::snGrad(alpha1)*fvc::interpolate(C)
//          sigma*lambda*fvc::interpolate(C)/dimChange
          - ghf*fvc::snGrad(rho)
      + fvc::flux(1e-1*(1-alpha1)*rho*(U-(Ubar*dimChange2))*dimChange1)
//      + fvc::flux(1e-1*(1-alpha1)*rho*(U)*dimChange1)
        )*rAUf*mesh.magSf()
    );

writting Fluctuating KE and Dissipation energy

   label nCells1 = returnReduce(mesh.cells().size(), sumOp<label>());
   vector Ubar(gSum(U)/nCells1);
   volScalarField magU(Foam::mag(U));
   volVectorField lapU(fvc::laplacian(U));
   volScalarField newnu(alpha1*nu1 + alpha2*nu2);
   volScalarField epsilonRes(U & lapU);

   scalar l = 0;
   scalar l0 = 0;
   scalar l1 = 0;
   scalar l2 = 0;
   scalar V = 0; 
   scalar dis = 0;     
   forAll(mesh.C(), I)
    {
        l0 = 0.5*((U[I].component(0)-Ubar.component(0))*(U[I].component(0)-Ubar.component(0)))*mesh.V()[I];
        l1 = 0.5*((U[I].component(1)-Ubar.component(1))*(U[I].component(1)-Ubar.component(1)))*mesh.V()[I];
        l2 = 0.5*((U[I].component(2)-Ubar.component(2))*(U[I].component(2)-Ubar.component(2)))*mesh.V()[I];
        l = l + (l0+l1+l2);
    V = V+mesh.V()[I];
        dis = dis -(epsilonRes[I]*newnu[I]*mesh.V()[I]);
    }
   l=l/V;
   dis=dis/V;
   // Create the KE file if not already created
   if (KE.empty())
     {
       Info<< "Kinetic Energy in present time step:" << l << endl;

         // File update
         if (Pstream::master())
         {
             fileName Kdat;
         word name_ = "Kdat";
         
         // Open new file at start up
         KE.reset(new OFstream("Kdat.dat"));
     }
    }
   
   if (Pstream::master())
     {
       KE() << runTime.timeName() << tab << l << tab << dis << endl;
     }

The issue is I am getting monotonically decreasing KE. It is not fluctuating even for a long run. I am using the same parameter as in the example case of Gerris.


my nu=1e-2, rho=1 for both the fluid, alpha is 0 everywhere for all the time steps, boundary condition cyclic for all the field. I tried running case in the finest level 128*128*128 also.


Not sure what is the cause for this. Any help is deeply appreciated.


Thanks


krishna kant