[pruthvi1991]

Hello everybody,

I'm trying to simulate a plunging and pitching airfoil. The pitch amplitude is upto 70 degrees and plunge amplitude is upto 1 chord length. Therefore a deforming mesh did not seem very wise.

I went through a paper by kinsey and dumas and they have implemented a solver in the heaving reference frame by adding a source term to the Navier stokes. This means that the N-S equation has a time varying body force term in the RHS. The time varying term looks like this.

F = F*sin(w*t)

Note : Rotation is taken care of by a sliding AMI.

I was able to implement this in pimpleFoam by the following additions to the pimpleFoam.C code and compile it with no issues. Here is the repository for those who prefer that and want test what I did.

int main(int argc, char *argv[])
{
const dimensionedScalar gunits("gunits", dimensionSet(0,1,-2,0,0,0,0), 0.01574684362);

    #include "setRootCase.H"
    #include "createTime.H"
    #include "createMesh.H"
    #include "readGravitationalAcceleration.H"
    #include "createFields.H"
    #include "createFvOptions.H"
    #include "initContinuityErrs.H"

    pimpleControl pimple(mesh);

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

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

    while (runTime.run())
    {
        #include "readTimeControls.H"
        #include "CourantNo.H"
        #include "setDeltaT.H"

        runTime++;
	
g=gunits*Foam::sin(runTime.value()*2*pi*freQ)*vector(0,1,0);
        Info<< "Time = " << runTime.timeName() << nl << endl;

        // --- Pressure-velocity PIMPLE corrector loop
        while (pimple.loop())
        {
            #include "UEqn.H"

            // --- Pressure corrector loop
            while (pimple.correct())
            {
                #include "pEqn.H"
            }

            if (pimple.turbCorr())
            {
                turbulence->correct();
            }
        }

        runTime.write();

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

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

    return 0;
}

Ueqn is as follows:

tmp<fvVectorMatrix> UEqn
(
    fvm::ddt(U)
  + fvm::div(phi, U)
  + turbulence->divDevReff(U)
 ==
    fvOptions(U)
);

UEqn().relax();

fvOptions.constrain(UEqn());

volScalarField rAU(1.0/UEqn().A());

if (pimple.momentumPredictor())
{
   

	
	

			
				 solve(UEqn() == g -fvc::grad(p));
			
		
    fvOptions.correct(U);
}

I tried the same with pimpleDyMFoam and I ran into the following error.

Making dependency list for source file inertial_pimpleDyMFoam.C
SOURCE=inertial_pimpleDyMFoam.C ;  g++ -m64 -Dlinux64 -DWM_DP -Wall -Wextra -Wno-unused-parameter -Wold-style-cast -Wnon-virtual-dtor -O3  -DNoRepository -ftemplate-depth-100 -I.. -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/turbulenceModels/incompressible/turbulenceModel -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/transportModels -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/transportModels/incompressible/singlePhaseTransportModel -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/finiteVolume/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/fvOptions/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/sampling/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/dynamicFvMesh/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/dynamicMesh/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/meshTools/lnInclude  -IlnInclude -I. -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/OpenFOAM/lnInclude -I/opt/OpenFOAM/OpenFOAM-2.3.x/src/OSspecific/POSIX/lnInclude   -fPIC -c $SOURCE -o Make/linux64GccDPOpt/inertial_pimpleDyMFoam.o
inertial_pimpleDyMFoam.C: In function ‘int main(int, char**)’:
inertial_pimpleDyMFoam.C:79:2: error: ‘g’ was not declared in this scope
  g=gunits*Foam::sin(runTime.value()*freQ)*vector(0,1,0);
  ^
In file included from inertial_pimpleDyMFoam.C:61:0:
/opt/OpenFOAM/OpenFOAM-2.3.x/src/finiteVolume/lnInclude/readTimeControls.H:38:8: warning: unused variable ‘maxDeltaT’ [-Wunused-variable]
 scalar maxDeltaT =
        ^
make: *** [Make/linux64GccDPOpt/inertial_pimpleDyMFoam.o] Error 1

Can you guys help me solve this issue. I would really appreciate it if you could help me fix the error

inertial_pimpleDyMFoam.C: In function ‘int main(int, char**)’:
inertial_pimpleDyMFoam.C:79:2: error: ‘g’ was not declared in this scope

I'm surprised that I was able to compile pimpleFoam since I haven't declared variable g anywhere. There was a similar thread a couple of years old and the implementation in this thread is derived from there.

[pruthvi1991]

Problem Solved !

I forgot to add #include "readGravitationalAcceleration.H" to pimpleDyMFoam solver and that was causing the trouble. Here the new code.

int main(int argc, char *argv[])
{
const dimensionedScalar gunits("gunits", dimensionSet(0,1,-2,0,0,0,0), 0.01574684362);

    #include "setRootCase.H"
    #include "createTime.H"
    #include "createDynamicFvMesh.H"
    #include "initContinuityErrs.H"
#include "readGravitationalAcceleration.H"

    pimpleControl pimple(mesh);

    #include "createFields.H"
    #include "createUf.H"
    #include "createFvOptions.H"
    #include "readTimeControls.H"
    #include "createPcorrTypes.H"
    #include "CourantNo.H"
    #include "setInitialDeltaT.H"

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

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

    while (runTime.run())
    {
        #include "readControls.H"
        #include "CourantNo.H"

        #include "setDeltaT.H"

        runTime++;

        g=gunits*Foam::sin(runTime.value()*freQ)*vector(0,1,0);

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

        mesh.update();

Cheers!