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Old   September 2, 2011, 18:27
Default algorithm
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nsreddy
Join Date: Sep 2010
Posts: 33
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hi openFoam users,


I am working on rhoCentralFoam, please suggest any book is better to understand the algorithm for rhoCentralFoam.
any documentation is available to understand the code given below,

Regards,



include "fvCFD.H"
#include "basicPsiThermo.H"
#include "zeroGradientFvPatchFields.H"
#include "fixedRhoFvPatchScalarField.H"

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

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

#include "createTime.H"
#include "createMesh.H"
#include "createFields.H"
#include "readThermophysicalProperties.H"
#include "readTimeControls.H"

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

#include "readFluxScheme.H"

dimensionedScalar v_zero("v_zero",dimVolume/dimTime, 0.0);

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

while (runTime.run())
{
// --- upwind interpolation of primitive fields on 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();

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;

// Reuse amaxSf for the maximum positive and negative fluxes
// estimated by the central scheme
amaxSf = max(mag(aphiv_pos), mag(aphiv_neg));

#include "compressibleCourantNo.H"
#include "readTimeControls.H"
#include "setDeltaT.H"

runTime++;

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

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;

volTensorField tauMC("tauMC", mu*dev2(fvc::grad(U)().T()));

// --- Solve density
solve(fvm::ddt(rho) + fvc::div(phi));

// --- 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)
);
rhoU = rho*U;
}

// --- 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)
);

solve
(
fvm::ddt(rhoE)
+ fvc::div(phiEp)
- fvc::div(sigmaDotU)
);

e = rhoE/rho - 0.5*magSqr(U);
e.correctBoundaryConditions();
thermo.correct();
rhoE.boundaryField() =
rho.boundaryField()*
(
e.boundaryField() + 0.5*magSqr(U.boundaryField())
);

if (!inviscid)
{
volScalarField k("k", thermo.Cp()*mu/Pr);
solve
(
fvm::ddt(rho, e) - fvc::ddt(rho, e)
- fvm::laplacian(thermo.alpha(), e)
+ fvc::laplacian(thermo.alpha(), e)
- fvc::laplacian(k, T)
);
thermo.correct();
rhoE = rho*(e + 0.5*magSqr(U));
}

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

runTime.write();

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

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

return 0;
}
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