[matthewshorter]

Hello,
I am looking to implement a moving mesh solver in foam-extend 3.1. The problem we are studying is a shock tunnel with an actuated valve connecting each section. We have successfully created a moving mesh based on the movingConeTopo case under icoDyMFoam, but we are having considerable difficulty implementing mesh motion into a compressible flow solver. Our goal is to effectively recreate "rhoCentralDyMFoam" for foam-extend. Using the SOD shock tube case, we have confirmed that the custom solver returns accurate results for a stationary mesh, but it crashes with a floating point error due to negative pressure occurring at the trailing side of the wall when a new mesh layer is added.
Here is the code for the relative flux we are currently using and is placed after the directed interpolation of primitive fields after faces:

if (mesh.moving()){

Info<<"Mesh flux is being accounted for\n";  
 phiv_pos -= mesh.phi();// fvc::meshPhi(rho,U);
        

 phiv_neg -= mesh.phi();//fvc::meshPhi(rho,U);



        Info <<endl <<phiv_neg <<endl<<"printed phiv_neg";
         }

and later here is the pressure made absolute

  phiEp +=mesh.phi()*(a_pos*p_pos + a_neg*p_neg);

I've attached the mesh at the point of crash. This is right after the dynamic mesh added a new layer. Note the negative temperature at the wall, which obviously blows up the solver....

Below is the solver in its entirety:

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     |
    \\  /    A nd           | Copyright (C) 2011-2015 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
    rhoCentralDyMFoam

Description
    Density-based compressible flow solver based on central-upwind schemes of
    Kurganov and Tadmor with support for mesh-motion and topology changes

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

#include "fvCFD.H"

#include "dynamicFvMesh.H"

#include "basicPsiThermo.H"

#include "zeroGradientFvPatchFields.H"
#include "fixedRhoFvPatchScalarField.H"

#include "motionSolver.H"

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

int main(int argc, char *argv[])
{
    #include "setRootCase.H"
    #include "createTime.H"
    #include "createDynamicFvMesh.H"

    #include "createFields.H"
    #include "readTimeControls.H"
#include "readThermophysicalProperties.H"   //?xz
    // * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

    #include "readFluxScheme.H"

    dimensionedScalar v_zero("v_zero", dimVolume/dimTime, 0.0);
    scalar CoNum = 0.0;
    scalar meanCoNum = 0.0;
    Info<< "\nStarting time loop\n" << endl;
    while (runTime.run())
      {
    runTime++;
        Info<< "Time = " << runTime.timeName() << nl << endl;
    bool meshChanged =        mesh.update();
    reduce(meshChanged, orOp<bool>());
        // --- Directed interpolation of primitive fields onto faces
        surfaceScalarField rho_pos=fvc::interpolate(rho, pos,"reconstruct(rho)");
        surfaceScalarField rho_neg=fvc::interpolate(rho, neg,"reconstruct(rho)");

        surfaceVectorField rhoU_pos=fvc::interpolate(rhoU, pos,"reconstruct(U)");
        surfaceVectorField rhoU_neg=fvc::interpolate(rhoU, neg, "reconstruct(U)");

        volScalarField rPsi= 1.0/psi;
        surfaceScalarField rPsi_pos=fvc::interpolate(rPsi, pos,"reconstruct(T)");
        surfaceScalarField rPsi_neg=fvc::interpolate(rPsi, neg,"reconstruct(T)");

        surfaceScalarField e_pos=fvc::interpolate(e, pos,"reconstruct(T)");
        surfaceScalarField e_neg=fvc::interpolate(e, neg,"reconstruct(T)");
        surfaceVectorField U_pos= rhoU_pos/rho_pos;
        surfaceVectorField U_neg = rhoU_neg/rho_neg;
        surfaceScalarField p_pos= rho_pos*rPsi_pos;
        surfaceScalarField p_neg = rho_neg*rPsi_neg;
        surfaceScalarField phiv_pos= U_pos & mesh.Sf();
        surfaceScalarField phiv_neg= U_neg & mesh.Sf();






    if (mesh.moving()){

Info<<"Mesh flux is being accounted for\n";  
 phiv_pos -= mesh.phi();// fvc::meshPhi(rho,U);
        

 phiv_neg -= mesh.phi();//fvc::meshPhi(rho,U);



        Info <<endl <<phiv_neg <<endl<<"printed phiv_neg";
         }

    Info<<"  adjusted for moving mesh ";
        volScalarField c= sqrt(thermo.Cp()/thermo.Cv()*rPsi);

    surfaceScalarField cSf_pos =         fvc::interpolate(c, pos,"reconstruct(T)")*mesh.magSf() ;
        surfaceScalarField cSf_neg=    fvc::interpolate(c, neg,"reconstruct(T)")*mesh.magSf();

        surfaceScalarField ap =   max(max(phiv_pos + cSf_pos, phiv_neg + cSf_neg), v_zero);
        surfaceScalarField am =  min(min(phiv_pos - cSf_pos, phiv_neg - cSf_neg), v_zero);

        surfaceScalarField a_pos= ap/(ap - am);

        surfaceScalarField amaxSf("amaxSf", max(mag(am), mag(ap)));
    
        surfaceScalarField aSf= am*a_pos;

        if (fluxScheme == "Tadmor")
        {
            aSf = -0.5*amaxSf;
            a_pos = 0.5;
        }

        surfaceScalarField a_neg= 1.0 - a_pos;

        phiv_pos *= a_pos;
        phiv_neg *= a_neg;

        surfaceScalarField aphiv_pos= phiv_pos - aSf;
        surfaceScalarField aphiv_neg= phiv_neg + aSf;



        amaxSf = max(mag(aphiv_pos), mag(aphiv_neg));
    
        #include "compressibleCourantNo.H"
    #include "readTimeControls.H"
    #include "setDeltaT.H"

       surfaceScalarField phi("phi",aphiv_pos*rho_pos + aphiv_neg*rho_neg);


        surfaceVectorField phiUp=
            (aphiv_pos*rhoU_pos + aphiv_neg*rhoU_neg)
          + (a_pos*p_pos + a_neg*p_neg)*mesh.Sf();

        surfaceScalarField phiEp=
            aphiv_pos*(rho_pos*(e_pos + 0.5*magSqr(U_pos)) + p_pos)
          + aphiv_neg*(rho_neg*(e_neg + 0.5*magSqr(U_neg)) + p_neg)
          + aSf*p_pos - aSf*p_neg;




      phiEp +=mesh.phi()*(a_pos*p_pos + a_neg*p_neg);

 Info << "\n print out check phiEp\n";

    Info << "\n beginning to solve the density and momentum equations\n";

//        volScalarField muEff("muEff", turbulence->muEff());
        volTensorField tauMC("tauMC", mu*dev2(fvc::grad(U)().T()));



    // solve density

        solve(fvm::ddt(rho) + fvc::div(phi));
    //Info << "Solving Momentum\n";
        // --- Solve momentum
        solve(fvm::ddt(rhoU) + fvc::div(phiUp));
    
        U.dimensionedInternalField() =
            rhoU.dimensionedInternalField()
           /rho.dimensionedInternalField();
        U.correctBoundaryConditions();
        rhoU.boundaryField() = rho.boundaryField()*U.boundaryField();
    volScalarField rhoBydt(rho/runTime.deltaT());
        if (!inviscid)
        {
            solve
            (
                fvm::ddt(rho, U) - fvc::ddt(rho, U)
              - fvm::laplacian(mu, U)
              - fvc::div(tauMC)
            );
      Info << "Flow is not inviscid";
          rhoU = rho*U;
        }
    //Info <<"Define sigmaDotU\n";
        // --- Solve energy
        surfaceScalarField sigmaDotU=(
                fvc::interpolate(mu)*mesh.magSf()*fvc::snGrad(U)
              + (mesh.Sf() & fvc::interpolate(tauMC))
            )
            & (a_pos*U_pos + a_neg*U_neg);
    Info<<"Solving Energy Eqn\n";
        solve
        (
            fvm::ddt(rhoE)
          + fvc::div(phiEp)
      -fvc::div(sigmaDotU)         
        );

        e = rhoE/rho - 0.5*magSqr(U);
        e.correctBoundaryConditions();
        thermo.correct();
    //Info <<"\n corrected thermo and using the solve functions \n";
        rhoE.boundaryField() =
            rho.boundaryField()*
            (
                e.boundaryField() + 0.5*magSqr(U.boundaryField())
            );

        if (!inviscid)
        {
        //turned off turbulence for now MS 6/7/16
            solve
            (
                fvm::ddt(rho, e) - fvc::ddt(rho, e)
        - fvm::laplacian(thermo.alpha(), e)
            );
            thermo.correct();
            rhoE = rho*(e + 0.5*magSqr(U));
        }

        p.dimensionedInternalField() =
            rho.dimensionedInternalField()
           /psi.dimensionedInternalField();
        p.correctBoundaryConditions();
        rho.boundaryField() = psi.boundaryField()*p.boundaryField();

    // turbulence->correct(); //see above; turned off 6/7/16 MS

        runTime.write();

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

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

    return 0;
}

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

[2538sukham]

Have you solved this particular issue? When layer addition or removal occurs, the simulation crashed. I am using foamExtend 3.2 and the LAR is based on linearValveLayersFvMesh. Is it to do with mapping when topoChange occurs?
With regards