[theBananaTrick]

Hello to all,

Following the post in compressibleInterFoam with conjugated heat transfer I started developing a chtMultiRegionCompressibleInterFoam with OFv2106

However, upon checking chtMultiRegionTwoPhaseEulerFoam I got several doubts regarding the solver. If anyone can give me hand with it, I would highly appreciate it.

1. Shound't the name of the solver be chtMultiRegionReactingTwoPhaseEulerFoam? It is solving the "YEqns". There are two solvers in ${FOAM_SOLVERS}/multiphase named twoPhaseEulerFoam. One accounts for reactions, the other does not.

2. Where is the initialMassFluid being used?
It is being calculated in line 284 of createFluidFields.H

initialMassFluid[i] =
        fvc::domainIntegrate(phaseSystemFluid[i].rho()).value();

and in line 44 of setRegionFluidFields.H assigned to a variable called initialMass. But where is it being used in the calculations?


3. Any particular reason for compressibleInterFoam not using the pRefCell, pRefValue? And where is it being used in chtMultiRegionTwoPhaseEulerFoam ?

Finally, I would like to know how to compute the Courant number for a multiRegion case where dt can is based on the Courant number and Alpha Courant number.
In compressibleInterFoam, ignoring LTS, this is being calculated and defined from line 104-106 of compressibleInterFoam.C

src/finiteVolume/cfdTools/incompressible/CourantNo.H
scalar CoNum = 0.0;
scalar meanCoNum = 0.0;
{
   scalarField sumPhi
   (
       fvc::surfaceSum(mag(phi))().primitiveField()
   );

   CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();

   meanCoNum =
       0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
}

Info<< "Courant Number mean: " << meanCoNum   << " max: " << CoNum << endl;


applications/solvers/multiphase/VoF/alphaCourantNo.H
scalar maxAlphaCo
(
   runTime.controlDict().get<scalar>("maxAlphaCo")
);

scalar alphaCoNum = 0.0;
scalar meanAlphaCoNum = 0.0;

if (mesh.nInternalFaces())
{
   scalarField sumPhi
   (
       mixture.nearInterface()().primitiveField()
      *fvc::surfaceSum(mag(phi))().primitiveField()
   );

   alphaCoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();

   meanAlphaCoNum =
       0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();
}

Info<< "Interface Courant Number mean: " << meanAlphaCoNum   << " max: " << alphaCoNum << endl;

applications/solvers/multiphase/VoF/setDeltaT.H
if (adjustTimeStep)
{
   scalar maxDeltaTFact =
       min(maxCo/(CoNum + SMALL), maxAlphaCo/(alphaCoNum + SMALL));

   scalar deltaTFact = min(min(maxDeltaTFact, 1.0 + 0.1*maxDeltaTFact), 1.2);

   runTime.setDeltaT
   (
       min
       (
           deltaTFact*runTime.deltaTValue(),
           maxDeltaT
       )
   );

   Info<< "deltaT = " <<  runTime.deltaTValue() << endl;
}

For the multiRegion case with this do: (?)

   scalar CoNum = -GREAT;
   scalar alphaCoNum = -GREAT;
   scalar maxAlphaCo = -GREAT;

   forAll(fluidRegions, regionI)
   {
       scalar CoNumI = 0.0;
       scalarField sumPhi
       (
           fvc::surfaceSum(mag(phiFluid[regionI]))().primitiveField()
       );

       CoNumI = 0.5*gMax(sumPhi/fluidRegions[regionI].V().field())*runTime.deltaTValue();
       CoNum = max(CoNumI, CoNum);

       // Calculation of alphaCourant.H from applications/solvers/multiphase/VoF/alphaCourantNo.H
       maxAlphaCo = max(maxAlphaCo, fluidRegions[regionI].time().controlDict().get<scalar>("maxAlphaCo"));

       scalar alphaCoNumI = 0.0;

       if (fluidRegions[regionI].nInternalFaces())
       {
           scalarField sumPhi
           (
               mixtureFluid[regionI].nearInterface()().primitiveField()
               *fvc::surfaceSum(mag(phiFluid[regionI]))().primitiveField()
           );

           alphaCoNumI = 0.5*gMax(sumPhi/fluidRegions[regionI].V().field())*runTime.deltaTValue();
       }

       alphaCoNum = max(alphaCoNumI, alphaCoNum);
   }

[oscar_zagal]

Hello there

With respect your first question, there are no boundary conditions about species, then I don't understand why the solver solves that equation, did you find the reason?