Project 3- Adding a temperature dictionary to the incompressible icoFoam case to solve the energy equation
Adding temperature equation to icoFoam solver:
Solver setup:
1. IcoFoam solver is copied from $FOAM_SOLVERS/incompressible folder to $FOAM_RUN. The folder is renamed to icoTempFoam. icoFoam.C file is renamed to icoTempFoam.cpp and Make/files is updated for this change as shown below to create the executable named icoTempFoam in $FOAM_USER_APPBIN
Make/files:
icoTempFoam.cpp
EXE = $(FOAM_USER_APPBIN)/icoTempFoam2. createField.H file is modified to read "kappa" dimensioned scalar from transport properties IOobject. A geometric scalar field 'T' is created to be solved in the domain.
Info<< "Reading transportProperties\n" << endl;
IOdictionary transportProperties
(
IOobject
(
"transportProperties",
runTime.constant(),
mesh,
IOobject::MUST_READ_IF_MODIFIED,
IOobject::NO_WRITE
)
);
dimensionedScalar nu
(
"nu",
dimViscosity,
transportProperties
);
dimensionedScalar kappa
(
"kappa",
dimensionSet(0,2,-1,0,0,0,0),
transportProperties
);
Info<< "Reading field p\n" << endl;
volScalarField p
(
IOobject
(
"p",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);
Info<< "Reading field U\n" << endl;
volVectorField U
(
IOobject
(
"U",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);
Info<< "Reading field T\n" << endl;
volScalarField T
(
IOobject
(
"T",
runTime.timeName(),
mesh,
IOobject::MUST_READ,
IOobject::AUTO_WRITE
),
mesh
);
#include "createPhi.H"
label pRefCell = 0;
scalar pRefValue = 0.0;
setRefCell(p, mesh.solutionDict().subDict("PISO"), pRefCell, pRefValue);
mesh.setFluxRequired(p.name());3. The icoTempFoam.cpp file is updated as shown below to add the temperature equation. This equation is solved to give temperature field outside the piso loop using the final calculated values of U at the end of each time-step.
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | www.openfoam.com
\\/ M anipulation |
-------------------------------------------------------------------------------
Copyright (C) 2011-2016 OpenFOAM Foundation
Copyright (C) 2019 OpenCFD Ltd.
-------------------------------------------------------------------------------
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
icoFoam
Group
grpIncompressibleSolvers
Description
Transient solver for incompressible, laminar flow of Newtonian fluids.
\heading Solver details
The solver uses the PISO algorithm to solve the continuity equation:
\f[
\div \vec{U} = 0
\f]
and momentum equation:
\f[
\ddt{\vec{U}}
+ \div \left( \vec{U} \vec{U} \right)
- \div \left(\nu \grad \vec{U} \right)
= - \grad p
\f]
Where:
\vartable
\vec{U} | Velocity
p | Pressure
\endvartable
\heading Required fields
\plaintable
U | Velocity [m/s]
p | Kinematic pressure, p/rho [m2/s2]
\endplaintable
\*---------------------------------------------------------------------------*/
#include "fvCFD.H"
#include "pisoControl.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
int main(int argc, char *argv[])
{
argList::addNote
(
"Transient solver for incompressible, laminar flow"
" of Newtonian fluids."
);
#include "postProcess.H"
#include "addCheckCaseOptions.H"
#include "setRootCaseLists.H"
#include "createTime.H"
#include "createMesh.H"
pisoControl piso(mesh);
#include "createFields.H"
#include "initContinuityErrs.H"
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Info<< "\nStarting time loop\n" << endl;
while (runTime.loop())
{
Info<< "Time = " << runTime.timeName() << nl << endl;
#include "CourantNo.H"
// Momentum predictor
fvVectorMatrix UEqn
(
fvm::ddt(U)
+ fvm::div(phi, U)
- fvm::laplacian(nu, U)
);
if (piso.momentumPredictor())
{
solve(UEqn == -fvc::grad(p));
}
// --- PISO loop
while (piso.correct())
{
volScalarField rAU(1.0/UEqn.A());
volVectorField HbyA(constrainHbyA(rAU*UEqn.H(), U, p));
surfaceScalarField phiHbyA
(
"phiHbyA",
fvc::flux(HbyA)
+ fvc::interpolate(rAU)*fvc::ddtCorr(U, phi)
);
adjustPhi(phiHbyA, U, p);
// Update the pressure BCs to ensure flux consistency
constrainPressure(p, U, phiHbyA, rAU);
// Non-orthogonal pressure corrector loop
while (piso.correctNonOrthogonal())
{
// Pressure corrector
fvScalarMatrix pEqn
(
fvm::laplacian(rAU, p) == fvc::div(phiHbyA)
);
pEqn.setReference(pRefCell, pRefValue);
pEqn.solve(mesh.solver(p.select(piso.finalInnerIter())));
if (piso.finalNonOrthogonalIter())
{
phi = phiHbyA - pEqn.flux();
}
}
#include "continuityErrs.H"
U = HbyA - rAU*fvc::grad(p);
U.correctBoundaryConditions();
}
fvScalarMatrix TEqn
(
fvm::ddt(T)
+ fvm::div(phi, T)
- fvm::laplacian(kappa, T)
);
TEqn.solve();
runTime.write();
runTime.printExecutionTime(Info);
}
Info<< "End\n" << endl;
return 0;
}
// ************************************************************************* //
4. wmake is called from inside icoTempFoam folder to compile the solver icoTempFoam in $FOAM_USER_APPBIN
Case setup:
1. Copy the tutorial $FOAM_TUTORIALS/incompressible/icoFoam/Cavity/Cavity to $FOAM_RUN folder and rename it to CavityTemp
2. Add a temperature boundary condition file in 0 folder as T file shown below. Moving wall at top is set at 400 [K] and internal temperature is set as 300 [K].
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2112 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 0 0 1 0 0 0];
internalField uniform 300;
boundaryField
{
movingWall
{
type fixedValue;
value uniform 400;
}
fixedWalls
{
type zeroGradient;
}
frontAndBack
{
type empty;
}
}
// ************************************************************************* //
3. constant/transportProperties file is updated to include the 'kappa' constant as shown below
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2112 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object transportProperties;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
nu 0.01;
kappa [ 0 2 -1 0 0 0 0 ] 0.001;
// ************************************************************************* //
4. system/fvSchemes file is updated to include the divergence and laplacian schemes for T. div(phi,T) is set to Gauss linear. laplacian(kappa,T) in TEqn will use the default laplacian scheme, Gauss linear orthogonal, set in file.
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2112 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
ddtSchemes
{
default Euler;
}
gradSchemes
{
default Gauss linear;
grad(p) Gauss linear;
}
divSchemes
{
default none;
div(phi,U) Gauss linear;
div(phi,T) Gauss linear;
}
laplacianSchemes
{
default Gauss linear orthogonal;
}
interpolationSchemes
{
default linear;
}
snGradSchemes
{
default orthogonal;
}
// ************************************************************************* //
5. system/fvSolution is updated to include the solver settings for T. smoothSolver with symGaussSeidel smoother is used with tolerance of 1e-7 and relative tolerance set to 0.
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2112 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
solvers
{
p
{
solver PCG;
preconditioner DIC;
tolerance 1e-06;
relTol 0.05;
}
pFinal
{
$p;
relTol 0;
}
U
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-05;
relTol 0;
}
T
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-07;
relTol 0;
}
}
PISO
{
nCorrectors 2;
nNonOrthogonalCorrectors 0;
pRefCell 0;
pRefValue 0;
}
// ************************************************************************* //
Solution and Results:
1. endTime is set to 1.5 in system/controlDict to increase the simulation time and show temperature development profile in the domain.
2. icoTempFoam solver is called from CavityTemp folder, which solves the case using our custom solver for 1.5 [s] simulation time. Solution converges well in each time-step judging by the residuals
3. Solution results are opened from paraFoam and profile of temperature is visualized as shown below.