[fghiloufi]

Hello OpenFOAM Community,

I am working on an elasticFlap simulation in a wind tunnel, where the fluid is compressible air. However, I am facing a floating point exception during the simulation run, and I can't seem to resolve it. Here are the details of my setup:


Floating point exception (core dumped)


Model Description:

Geometry: An elastic flap in a wind tunnel.
Fluid: Compressible air.


Mesh: Generated using ANSYS Workbench and converted to OpenFOAM using fluent3DMeshToFoam.

Boundary Conditions:

I will attach screenshots of my boundary condition settings.
9
(
inlet
{
type patch;
nFaces 5200;
startFace 3380182;
}
outlet
{
type patch;
nFaces 5200;
startFace 3385382;
}
channel-end
{
type wall;
inGroups 1(wall);
nFaces 8700;
startFace 3390582;
}
channel-front
{
type wall;
inGroups 1(wall);
nFaces 7250;
startFace 3399282;
}
channel-middle
{
type wall;
inGroups 1(wall);
nFaces 45240;
startFace 3406532;
}
overset-top
{
type wall;
nFaces 730;
startFace 3451772;
}
overset-bottom
{
type overset;
inGroups 1(wall);
nFaces 910;
startFace 3452502;
}
overset-sides
{
type overset;
nFaces 10126;
startFace 3453412;
}
couple-flap
{
type wall;
inGroups 1(wall);
nFaces 7740;
startFace 3463538;
}
)
u: overset-bottom
{
type overset;

}
overset-sides
{
type overset;

}
overset-top
{
type uniformFixedValue;
uniformValue (0 0 0);
}

inlet
{
type fixedValue;
value $internalField;
}

outlet
{
type inletOutlet;
inletValue uniform (0 0 0);
value $internalField;
}
"channel.*"
{
type uniformFixedValue;
uniformValue (0 0 0);
}
couple-flap
{
// type uniformFixedValue;
// uniformValue (0 0 0);
type movingWallVelocity;
value $internalField;
}
}
p: dimensions [1 -1 -2 0 0 0 0];
pressure 101325;
internalField uniform $pressure;

boundaryField
{
overset-bottom
{
type overset;

}
overset-sides
{
type overset;

}
overset-top
{
type zeroGradient;
}
inlet
{
type zeroGradient;
// type fixedValue;
// value uniform 1;
}
outlet
{
type fixedValue;
value $internalField;
}
"channel.*"
{
type zeroGradient;
}
couple-flap
{
type zeroGradient;
}
}
T: dimensions [0 0 0 1 0 0 0];
temperature 288.16;
internalField uniform $temperature;

boundaryField
{
overset-bottom
{
type overset;

}
overset-sides
{
type overset;

}
overset-top
{
type zeroGradient;

}
inlet
{
type zeroGradient;
}
outlet
{
type fixedValue;
value $internalField;
}
"channel.*"
{
type zeroGradient;
}
couple-flap
{
type zeroGradient;
}
}



Solver Setup:

I will attach my system, controlDict, and solver files for reference.
controlDict: ibs (overset fvMotionSolvers);

DebugSwitches
{
overset 0;
dynamicOversetFvMesh 0;
cellVolumeWeight 0;
}
application overRhoPimpleDyMFoam;

startFrom startTime;

startTime 0;

stopAt endTime;

endTime 2;

deltaT 2.5e-4;

writeControl timeStep; //adjustableRunTime;

writeInterval 1;

purgeWrite 0;

writeFormat ascii;

writePrecision 10;

writeCompression off;

timeFormat general;

timePrecision 6;

runTimeModifiable true;

adjustTimeStep no;

maxCo 0.9;
svschemes: ddtSchemes
{
default Euler;
}

gradSchemes
{
default Gauss linear;
}

divSchemes
{
// default none;

/
default none;
div(phi,U) Gauss limitedLinearV 1;
div(phi,k) Gauss limitedLinear 1;
div(phi,epsilon) Gauss limitedLinear 1;
div(phi,R) Gauss limitedLinear 1;
div(R) Gauss limitedLinear 1;
div(phi,omega) Gauss limitedLinear 1;
div(phid,p) Gauss limitedLinear 1;
div(phi,K) Gauss limitedLinear 1;
div(phi,e) Gauss limitedLinear 1;
div(phi,h) Gauss limitedLinear 1;
div(meshPhi,p) Gauss linear;
div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
div((nuEff*dev2(T(grad(U))))) Gauss linear;

}


laplacianSchemes
{
//default Gauss linear limited 0.5;
default Gauss linear corrected;
laplacian(diffusivity,cellDisplacement) Gauss linear corrected;
}



interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}

wallDist
{
method meshWave;
}

oversetInterpolation
{
// cellVolumeWeight inverseDistance leastSquares trackingInverseDistance
// method inverseDistance; Absturz
method cellVolumeWeight;
// method leastSquares;
}

fluxRequired
{
default no;
p ;
pcorr ;
}


fvsolution: solvers
{
cellDisplacement
{
solver PCG;
preconditioner DIC;

tolerance 1e-06;
relTol 0;
maxIter 100;
}
cellDisplacementFinal
{
$cellDisplacement;
}


p
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-11;
relTol 0.01;
}

pFinal
{
$p;
relTol 0;
}

pcorr
{
$pFinal;
}

pcorrFinal
{
$pcorr;
relTol 0;
}
"(rho|h)"
{
solver PBiCGStab;
preconditioner DILU;
tolerance 1e-8;
relTol 0.1;
}

"(rho|h)Final"
{
$rho;
tolerance 1e-8;
relTol 0;
}
"(U|k|epsilon)"
{
solver smoothSolver;
smoother symGaussSeidel;
tolerance 1e-6;
relTol 0;
}

"(U|k|epsilon)Final"
{
$U;
tolerance 1e-6;
relTol 0;
}
}

PIMPLE
{
momentumPredictor false;
correctPhi true;
nOuterCorrectors 100;
nCorrectors 4;
nNonOrthogonalCorrectors 0;
ddtCorr false;
residualControl
{
"(U|k|epsilon|p)"
{
relTol 0;
tolerance 0.0001;
}

}
}

relaxationFactors
{
"p.*" 0.3;
"rho.*" 1;
"(U|h|k|epsilon|omega).*" 0.7;

}

Steps Taken:

I have varied several parameters in the simulation (e.g., mesh refinement, time step size, Courant number), but the floating point exception persists.
Additional Information:
I have run checkMesh, and the results show that the mesh is good.
I have previously run the same case using incompressible flow (air) with the same mesh, and the simulation converged well without any issues.

Would you be able to provide some advice or tips on how to troubleshoot this? I would greatly appreciate any insights!

If you need more information, feel free to let me know, and I will gladly provide additional details.

Thank you!

[fghiloufi]

Geometry: An elastic flap in a wind tunnel.
https://owncloud.scai.fraunhofer.de/s/3ewHJoAZEbcamGM


Mesh:
https://owncloud.scai.fraunhofer.de/s/GQtfgasP63JGGPx