[unilord]

Hey guys,

I am performing a centrifugal pump simulation in OF11. At the moment I am trying a transient approach, since I have already ran all the steady state simulations I needed. The transient simulation is started with the results from the steady state simulation, since I do not care for the startup of the pump. It runs at 620 rpm, with 0.0063m^3/s flow rate. It is a relatively small pump. The simulation is dynamic, using the sliding mesh approach and the new Non Conformal Coupling feature from the foundation branch.

I am using vanLeer schemes for turbulence (using kEpsilon model) and LUST for convective term. No cell/face limiters are being used (although I already tried and it didn't improve anything). When using Euler for the ddt schemes, no error appears. However, when using Crank Nicolson 0.1 to 0.9 a floating point exception occurs.

--------------------------------------------------------------------------
Primary job  terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
--------------------------------------------------------------------------
--------------------------------------------------------------------------
mpirun noticed that process rank 3 with PID 0 on node omnideayoga-Yoga-Slim-7-Pro-14ARH7 exited on signal 8 (Floating point exception).

This is my mesh quality parameters:

Mesh stats
    points:           801625
    faces:            2283864
    internal faces:   2148432
    cells:            741672
    faces per cell:   5.97609
    boundary patches: 30
    point zones:      0
    face zones:       3
    cell zones:       1

Overall number of cells of each type:
    hexahedra:     723936
    prisms:        17736
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
   *Number of regions: 3
    The mesh has multiple regions which are not connected by any face.
  <<Writing region information to "0/cellToRegion"
  <<Writing region 0 with 335968 cells to cellSet region0
  <<Writing region 1 with 246432 cells to cellSet region1
  <<Writing region 2 with 159272 cells to cellSet region2

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points   Surface topology                  
    NCC3_2              6976     7412     ok (non-closed singly connected)  
    wall_3_2            1680     1802     ok (non-closed singly connected)  
    wall_3_3            2000     2142     ok (non-closed singly connected)  
    wall_3_4            2240     2397     ok (non-closed singly connected)  
    wall_3_layers       28276    28964    ok (non-closed singly connected)  
    wall_tongue_1       128      153      ok (non-closed singly connected)  
    wall_3_1            1360     1462     ok (non-closed singly connected)  
    wall_tongue_2       128      153      ok (non-closed singly connected)  
    wall_tongue_3       160      187      ok (non-closed singly connected)  
    outlet              784      850      ok (non-closed singly connected)  
    wall_4              4480     4794     ok (non-closed singly connected)  
    wall_4_layers       13720    14100    ok (non-closed singly connected)  
    NCC2_1              2432     2584     ok (non-closed singly connected)  
    NCC2_3              6976     7412     ok (non-closed singly connected)  
    blade_LE            320      408      ok (non-closed singly connected)  
    blade_pressure      7808     8364     ok (non-closed singly connected)  
    blade_suction       7936     8500     ok (non-closed singly connected)  
    blade_tip           448      544      ok (non-closed singly connected)  
    wall_2              30804    31908    ok (non-closed singly connected)  
    inlet               1852     1899     ok (non-closed singly connected)  
    NCC1_2              2432     2584     ok (non-closed singly connected)  
    wall_1              12492    12691    ok (non-closed singly connected)  
    nonConformalCouple_12_on_NCC1_20        0        ok (empty)                        
    nonConformalCouple_12_on_NCC2_10        0        ok (empty)                        
    nonConformalCouple_23_on_NCC2_30        0        ok (empty)                        
    nonConformalCouple_23_on_NCC3_20        0        ok (empty)                        
    nonConformalError_on_NCC2_30        0        ok (empty)                        
    nonConformalError_on_NCC1_20        0        ok (empty)                        
    nonConformalError_on_NCC3_20        0        ok (empty)                        
    nonConformalError_on_NCC2_10        0        ok (empty)                        

Checking geometry...
    Overall domain bounding box (-0.153983 -0.18447 -0.0123) (0.220992 0.482614 0.1647)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-3.87232e-17 -5.16145e-18 -6.18043e-16) OK.
    Max cell openness = 3.32906e-16 OK.
    Max aspect ratio = 13.8188 OK.
    Minimum face area = 9.82531e-08. Maximum face area = 1.4498e-05.  Face area magnitudes OK.
    Min volume = 1.23456e-10. Max volume = 2.82255e-08.  Total volume = 0.00389344.  Cell volumes OK.
    Mesh non-orthogonality Max: 54.0036 average: 7.95413
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 2.97155 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

End

These are my fvSchemes

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  11
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default        CrankNicolson 0.5;
}

gradSchemes
{
    default        Gauss linear;
}

divSchemes
{
    default                                     none;
    div(phi,k)                                 bounded Gauss vanLeer;
    div(phi,epsilon)                         bounded Gauss vanLeer;
    div(phi,U)                                 bounded Gauss LUST grad(U);
    div((nuEff*dev2(T(grad(U)))))   bounded Gauss linear;
}

laplacianSchemes
{
    default        Gauss linear corrected;
}

interpolationSchemes
{
    default        linear;
}

snGradSchemes
{
    default        corrected;
}

wallDist
{
    method Poisson;
}

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

These are my fvSolutions

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  11
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p
    {
        solver                    GAMG;
        tolerance                 1e-08;
        relTol                    0.01;
        smoother                  GaussSeidel;
        nCellsInCoarsestLevel     1000;
        //nSweeps                   200;
        minIter                   5;
    }
    
    pFinal
    {
        $p;
        tolerance          1e-08;
        relTol              0.0;
    }
    
    "pcorr.*"
    {
        $p;
        tolerance          1e-03;
        relTol              0.0;
    }

    U
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-08;
        //nSweeps         200;
        relTol          0.01;
        //type            coupled;
        //solver          PBiCGStab;
        //preconditioner  DILU;
        //tolerance       (1e-08 1e-08 1e-08);
        //tolerance       1e-14
        //relTol          (0 0 0);
        //relTol          0.0;
        minIter         3;  
    }
    
    UFinal
    {
        $U;
        tolerance    1e-10;
        relTol        0.0;
    }

    "(k|epsilon|omega)"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-08;
        relTol          0.01;
        //nSweeps         50;
        minIter        2;
    }

     "(k|epsilon|omega)Final"
    {
        solver          smoothSolver;
        smoother        GaussSeidel;
        tolerance       1e-10;
        relTol          0.0;
        //nSweeps         50;
        minIter        2;
    }
    
    MeshPhi
    {
        solver        smoothSolver;
        smoother      symGaussSeidel;
        tolerance     1e-2;
        relTol        0.0;
    }

}

potentialFlow
{
    nNonOrthogonalCorrectors 10;
}

PIMPLE
{
    correctMeshPhi          yes;
    momentumPredictor         yes;
    nNonOrthogonalCorrectors  2;
    nCorrectors               2;
    nOuterCorrectors          30;
    
    residualControl
    {
        p        1e-8;
        U        1e-10;
        k        1e-8;
        epsilon        1e-8;
    }
}

relaxationFactors
{
    fields
    {
        p               0.3;
        pFinal          1;
    }
    equations
    {
        "(U|k|omega)"            0.7;
        "(U|k|omega)Final"       1;
    }
}


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

basically it happens once it enters the second time step. Doesn't really matter how many outer iterations I run. Does someone have an idea of what might be happening? The complete log of the simulation is presented in the attached file.