[doon_1984]

Dear all foamers (Experts),
I am a new to OpenFOAM thus I apologised if I used some wrong descriptions. I am simulating a problem with flow past heated cylinder (2D). As per directions provided in the tutorial, I inculcate the energy equation in icofoam. I checked the case for laminar flow at Re = 100. The results are okie with Strouhal number = 0.157. I provide the temperature of 350K to cylinder rest boundary conditions are same as given in openfoam tutorial of flow past cylinder. I want to draw Nusselt number variation within the curve length along the cylinder. I don't what should I added in my control dic or the .C and .H files so that i can evaluate it. Secondly the same i want to draw static pressure along cylinder curve length. I saw many peoples posted for Nusselt number before, but exactly what to write in the files I can't get.

Please help me to resolve the issue.

Thanks the forum and group members.

[dewey]

You should take a look to this papers, it works for me. If you have some troubles, let me know.


http://www.tfd.chalmers.se/~hani/kur...esentation.pdf

http://www.tfd.chalmers.se/~hani/kur...ssonReport.pdf

[dewey]

What solver are you using? did you modify icofoam? why you didnt use buoyantBoussinesqPimpleFoam: Transient solver for buoyant, turbulent flow of incompressible fluids?

[doon_1984]

Thanks,
I am using icofoam. I modified my code according to tutorial.
/*---------------------------------------------------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration |
\\ / A nd | Copyright (C) 2011-2016 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
icoFoam

Description
Transient solver for incompressible, laminar flow of Newtonian fluids.

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

#include "fvCFD.H"
#include "pisoControl.H"

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

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

if (piso.finalNonOrthogonalIter())
{
phi = phiHbyA - pEqn.flux();
}
}
#include "continuityErrs.H"

U = HbyA - rAU*fvc::grad(p);
U.correctBoundaryConditions();
}

//paasive scalar transport equation-energy equation for heat transfer

fvScalarMatrix TEqn
(
fvm::ddt(T)
+ fvm::div(phi, T)
- fvm::laplacian(DT, T)
);

TEqn.relax();
TEqn.solve();


// Calculates dT/dy
Info<< "Calculating gradT" << endl;

label patchi = mesh.boundaryMesh().findPatchID("cylinder");

// calculate (dT/dy)_wall
//gradT.boundaryField()[patchi]=T.boundaryField()[patchi].snGrad();
gradT.boundaryFieldRef()[patchi]=T.boundaryFieldRef()[patchi].snGrad();

scalar area1 = gSum(mesh.magSf().boundaryField()[patchi]);
scalar sumField1 = 0;

if (area1 > 0)
{
sumField1 = gSum
(
mesh.magSf().boundaryField()[patchi]
* gradT.boundaryField()[patchi]
)/ area1;
}

Info<< " Average of gradT over patch 1 = " << sumField1 << endl;




//label patchi = mesh.boundaryMesh().findPatchID("myPatch");
//gradT.boundaryField()[patchi]=T.boundaryField()[patchi].snGrad();



runTime.write();

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

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

return 0;
}


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

[doon_1984]

The create field file
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.lookup("nu")
);

// DT thermal diffusion
dimensionedScalar DT
(
transportProperties.lookup("DT")
);

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
);
volScalarField gradT
(
IOobject
(
"gradT",
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::AUTO_WRITE
),
mesh,
dimensionedScalar
(
"gradT",
T.dimensions()/dimLength,
0
)

);

#include "createPhi.H"


label pRefCell = 0;
scalar pRefValue = 0.0;
setRefCell(p, mesh.solutionDict().subDict("PISO"), pRefCell, pRefValue);
mesh.setFluxRequired(p.name());

[doon_1984]

The Nusselt number and wall flux utility is also having .C file. I get confused that I have to copy the code in my icofoam .C and .H files.

regards

[svramana]

Originally Posted by doon_1984

The create field file
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.lookup("nu")
);

// DT thermal diffusion
dimensionedScalar DT
(
transportProperties.lookup("DT")
);

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
);
volScalarField gradT
(
IOobject
(
"gradT",
runTime.timeName(),
mesh,
IOobject::NO_READ,
IOobject::AUTO_WRITE
),
mesh,
dimensionedScalar
(
"gradT",
T.dimensions()/dimLength,
0
)

);

#include "createPhi.H"


label pRefCell = 0;
scalar pRefValue = 0.0;
setRefCell(p, mesh.solutionDict().subDict("PISO"), pRefCell, pRefValue);
mesh.setFluxRequired(p.name());

Hi, i need to calculate local Nusselt number variation along the surface length of porous square cylinder.In my case i have defined porous cylinder as porosity zones using topoSet and defined porosity as sink(Darcy-Forchheimer law).
so literally i don't have a wall/patch defined,while calculation gradT or Nusselt number.

what i mean to say is all about how to calculate Nusselt number on porouszone surface.

Regards,
S.V.Ramana

[milad092]

hi
anybody know about this error in openfoam?

create time
FOAM FATAL IO ERROR
cannot find file
from function regI0object::readstream()
in file db/regI0object/regI0objectRead.c at line 72