[happyFoamer]

Hi Foamer-Community,

I'm trying to simulate an Airfoil 2D with OpenFoam and run into divergence problems. I started with 100 m/s (AoA=2°) and increased the velocity step by step to now 180 m/s. For 200 m/s the simulation crashes after reaching about 800 iterations. The residuals of k and epsilon increase and they are bounded.
I use rhoPimpleFoam and the mesh should be fine. There are no warnings when running checkMesh. As turbulence model kEpsilon is activated. TimeStep is set to 1e-4. I'm running openFoam in a virtualbox.

The domain consists of one disk with one cell thickness. The airfoil is cut out in the center of the disk. So there are 3 boundaries: Airfoil(wall); Farfield(inlet and outlet to produce 360° polars); Symmetry_Plane(front and back side of the disk)

It would be great to get some advices. I tried a lot but nothing succeeded.

Here are some specifications of my case:

fvSolution:

solvers
{
    "(p)"
    {
        solver          PCG;
        preconditioner  DIC;
        tolerance       1e-06;
        relTol          0.001;
    }

    "(p)Final"
    {
        $p;
        relTol          0;
    }

    "(rho|U|e)"
    {
        solver          PBiCG;
        preconditioner  DILU;
        tolerance       1e-08;
        relTol          0.001;
    }

    "(rho|U|e)Final"
    {
        $U;
        relTol          0;
    }

    "(k|nTilda|epsilon)"
    {
        solver          GAMG;
        smoother        DILUGaussSeidel;
        tolerance       1e-08;
        relTol          0.001;
    }

    "(k|nTilda|epsilon)Final"
    {
        $U;
        relTol          0;
    }

}

PIMPLE
{
    momentumPredictor   yes;
    transonic           no;
    nOuterCorrectors    50;
    nCorrectors         1;
    nNonOrthogonalCorrectors 0;
    consistent          yes;
    SIMPLErho           yes;

    residualControl
    {
        "(U|k|epsilon)"
        {
            relTol          0;
            tolerance       0.0001;
        }
    }

    turbOnFinalIterOnly no;
}

relaxationFactors
{
    fields
    {
        "p.*"           1;
        "rho.*"         1;
    }
    equations
    {
        "U.*"           0.9;
        "(e|h)"         0.7;
        "(k|epsilon|omega).*" 0.8;
    }
}

thermophysicalProperties:
thermoType
{
    type            hePsiThermo;
    mixture         pureMixture;
    transport       sutherland;
    thermo          hConst;
    equationOfState perfectGas;
    specie          specie;
    energy          sensibleInternalEnergy;
}

mixture
{
    specie
    {
        molWeight   28.97;
    }
    thermodynamics
    {
        Cp          1007;
        Hf          0;
    }
    transport
    {
        As          1.458e-06;
        Ts          110.4;

    }
}

boundaries:

alphat:
dimensions      [1 -1 -1 0 0 0 0];

internalField   uniform 1e-3;

boundaryField
{
    Airfoil
    {
        type            compressible::alphatWallFunction;
        value           $internalField;
    }
    Symmetry
    {
        type            empty;

    }
    Farfield
    {
        type            calculated;
        value           $internalField;
    }
}

epsilon:
dimensions      [0 2 -3 0 0 0 0];

internalField   uniform 200;

boundaryField
{
    Airfoil
    {
        type            epsilonWallFunction;
        value           uniform 200;
    }
    Symmetry
    {
    type        empty;

    }
    Farfield
    {
        type            inletOutlet;
        inletValue      uniform 200;
        value           uniform 200;
    }
}

k:
dimensions      [0 2 -2 0 0 0 0];

internalField   uniform 1;

boundaryField
{
    Airfoil
    {
        type            kqRWallFunction;
        value           uniform 1;
    }
    Symmetry
    {
    type        empty;

    }
    Farfield
    {
        type            inletOutlet;
        inletValue      uniform 1;
        value           uniform 1;
    }
}

p:
dimensions      [1 -1 -2 0 0 0 0];

internalField   uniform 1.0e5;

boundaryField
{
    Airfoil
    {
        type            zeroGradient;
    }
    Symmetry
    {
        type            empty;
    }
    Farfield
    {
        type            fixedValue;
        value           $internalField;
    }
}

T: 
dimensions      [0 0 0 1 0 0 0];

internalField   uniform 288.15;

boundaryField
{

    Airfoil
    {
        type            zeroGradient;
    }
    Symmetry
    {
    type        empty;

    }
    Farfield
    {
        type            inletOutlet;
        value           $internalField;
        inletValue      $internalField;
    }
}

U:
dimensions [ 0 1 -1 0 0 0 0 ];

internalField uniform (99.94 3.49 0);

boundaryField
{
  Airfoil
  {
    type noSlip;
  }
  Symmetry_Plane
  {
    type empty;
  }
  Farfield
  {
    type freestream;
    freestreamValue uniform (99.939083 3.489950 0);
  }
}

Error:

[1] #0  Foam::error::printStack(Foam::Ostream&) at ??:?
[1] #1  Foam::sigFpe::sigHandler(int) at ??:?
[1] #2  ? in "/lib/x86_64-linux-gnu/libc.so.6"
[1] #3  Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::calculate() at ??:?
[1] #4  Foam::hePsiThermo<Foam::psiThermo, Foam::pureMixture<Foam::sutherlandTransport<Foam::species::thermo<Foam::hConstThermo<Foam::perfectGas<Foam::specie> >, Foam::sensibleInternalEnergy> > > >::correct() at ??:?
[1] #5  ? at ??:?
[1] #6  __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
[1] #7  ? at ??:?
[openfoam-VirtualBox:16350] *** Process received signal ***
[openfoam-VirtualBox:16350] Signal: Floating point exception (8)
[openfoam-VirtualBox:16350] Signal code:  (-6)
[openfoam-VirtualBox:16350] Failing at address: 0x3e800003fde
[openfoam-VirtualBox:16350] [ 0] /lib/x86_64-linux-gnu/libc.so.6(+0x354b0)[0x7fb0575734b0]
[openfoam-VirtualBox:16350] [ 1] /lib/x86_64-linux-gnu/libc.so.6(gsignal+0x38)[0x7fb057573428]
[openfoam-VirtualBox:16350] [ 2] /lib/x86_64-linux-gnu/libc.so.6(+0x354b0)[0x7fb0575734b0]
[openfoam-VirtualBox:16350] [ 3] /opt/openfoam5/platforms/linux64GccDPInt32Opt/lib/libfluidThermophysicalModels.so(_ZN4Foam11hePsiThermoINS_9psiThermoENS_11pureMixtureINS_19sutherlandTransportINS_7species6thermoINS_12hConstThermoINS_10perfectGasINS_6specieEEEEENS_22sensibleInternalEnergyEEEEEEEE9calculateEv+0x184)[0x7fb05cd58de4]
[openfoam-VirtualBox:16350] [ 4] /opt/openfoam5/platforms/linux64GccDPInt32Opt/lib/libfluidThermophysicalModels.so(_ZN4Foam11hePsiThermoINS_9psiThermoENS_11pureMixtureINS_19sutherlandTransportINS_7species6thermoINS_12hConstThermoINS_10perfectGasINS_6specieEEEEENS_22sensibleInternalEnergyEEEEEEEE7correctEv+0x2a)[0x7fb05cd6865a]
[openfoam-VirtualBox:16350] [ 5] rhoPimpleFoam[0x42ab96]
[openfoam-VirtualBox:16350] [ 6] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xf0)[0x7fb05755e830]
[openfoam-VirtualBox:16350] [ 7] rhoPimpleFoam[0x4328f9]
[openfoam-VirtualBox:16350] *** End of error message ***

Thanks a lot in advance! :-)