[gfilip]

Hello everyone,

I am using pimpleDyMFoam with a custom dynamicFvMesh to solve for the motion of a 2D circular cylinder with 1DOF (heave) with the standard SA model. I am having issues with the solver diverging after several time steps. The time step keeps decreasing to meet the maxCo criterion, while the actual Co oscillates and eventually blows up, resulting in the solver crashing. Here is a part of the log:

Courant Number mean: 0.181987 max: 57.4844
deltaT = 3.73109e-10
Time = 0.00065686

Pressure force = (-5.77062e+11 -1.75305e+13 1.484e-05)
Viscous force = (1.06804e+10 -3.28055e+09 4.6907e-05)
Total force = (-5.66381e+11 -1.75338e+13 6.1747e-05)
Pressure force = (-5.77062e+11 -1.75305e+13 1.484e-05)
Viscous force = (1.06804e+10 -3.28055e+09 4.6907e-05)
Total force = (-5.66381e+11 -1.75338e+13 6.1747e-05)
new force= (-5.66381e+11 -1.75338e+13 6.1747e-05)
damping force= (0 111.291 0)
spring force= (0 0.19882 0)
 displace component=                                 0.0298225
DILUPBiCG:  Solving for Ux, Initial residual = 0.00118393, Final residual = 6.46833e-07, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.000226988, Final residual = 1.6964e-07, No Iterations 1
DICPCG:  Solving for p, Initial residual = 0.936208, Final residual = 9.29128e-07, No Iterations 303
time step continuity errors : sum local = 2.91692e-12, global = 3.30302e-14, cumulative = 2.10666e-12
DILUPBiCG:  Solving for Ux, Initial residual = 0.0011032, Final residual = 2.14598e-08, No Iterations 1
DILUPBiCG:  Solving for Uy, Initial residual = 0.00026622, Final residual = 5.22804e-09, No Iterations 1
DICPCG:  Solving for p, Initial residual = 0.474501, Final residual = 9.38896e-07, No Iterations 298
time step continuity errors : sum local = 4.10823e-12, global = 4.30266e-14, cumulative = 2.14969e-12
DILUPBiCG:  Solving for nuTilda, Initial residual = 2.76369e-06, Final residual = 2.76369e-06, No Iterations 0
ExecutionTime = 24.02 s  ClockTime = 24 s

Courant Number mean: 0.0012636 max: 0.200559
deltaT = 4.47731e-10
Time = 0.00065686

Pressure force = (3.14683e+13 2.90887e+14 -0.000464347)
Viscous force = (6.73597e+09 -3.07824e+09 4.73848e-06)
Total force = (3.1475e+13 2.90884e+14 -0.000459609)
Pressure force = (3.14683e+13 2.90887e+14 -0.000464347)
Viscous force = (6.73597e+09 -3.07824e+09 4.73848e-06)
Total force = (3.1475e+13 2.90884e+14 -0.000459609)
new force= (3.1475e+13 2.90884e+14 -0.000459609)
damping force= (0 96.883 0)
spring force= (0 0.200467 0)
 displace component=                                 0.0309868
DILUPBiCG:  Solving for Ux, Initial residual = 0.016213, Final residual = 8.38248e-08, No Iterations 2
DILUPBiCG:  Solving for Uy, Initial residual = 0.0037189, Final residual = 6.18129e-07, No Iterations 1
DICPCG:  Solving for p, Initial residual = 0.614507, Final residual = 8.80742e-07, No Iterations 344
time step continuity errors : sum local = 2.19871e-12, global = 1.48693e-14, cumulative = 2.16456e-12
DILUPBiCG:  Solving for Ux, Initial residual = 0.0376498, Final residual = 4.48819e-09, No Iterations 2
DILUPBiCG:  Solving for Uy, Initial residual = 0.00476686, Final residual = 1.9605e-06, No Iterations 1
DICPCG:  Solving for p, Initial residual = 0.494856, Final residual = 9.71665e-07, No Iterations 320
time step continuity errors : sum local = 8.84475e-12, global = 5.15065e-14, cumulative = 2.21606e-12
DILUPBiCG:  Solving for nuTilda, Initial residual = 1.94363e-05, Final residual = 1.35167e-08, No Iterations 1
bounding nuTilda, min: -1.48587e-17 max: 3.92394 average: 0.00253206
ExecutionTime = 26.15 s  ClockTime = 26 s

Courant Number mean: 0.00577774 max: 0.207404
deltaT = 5.37277e-10
Time = 0.000656861

Pressure force = (2.07155e+09 -5.18228e+15 0.0122243)
Viscous force = (2.52242e+09 -1.35877e+11 5.65746e-05)
Total force = (4.59397e+09 -5.18242e+15 0.0122809)
Pressure force = (2.07155e+09 -5.18228e+15 0.0122243)
Viscous force = (2.52242e+09 -1.35877e+11 5.65746e-05)
Total force = (4.59397e+09 -5.18242e+15 0.0122809)
new force= (4.59397e+09 -5.18242e+15 0.0122809)
damping force= (0 383.723 0)
spring force= (0 0.208293 0)
 displace component=                                 0.0100557
DILUPBiCG:  Solving for Ux, Initial residual = 0.207082, Final residual = 3.86788e-06, No Iterations 3
DILUPBiCG:  Solving for Uy, Initial residual = 0.139973, Final residual = 2.91468e-06, No Iterations 3
DICPCG:  Solving for p, Initial residual = 0.98152, Final residual = 9.09526e-07, No Iterations 333
time step continuity errors : sum local = 2.52805e-11, global = 4.02247e-14, cumulative = 2.25629e-12
DILUPBiCG:  Solving for Ux, Initial residual = 0.40134, Final residual = 6.16425e-06, No Iterations 4
DILUPBiCG:  Solving for Uy, Initial residual = 0.0181964, Final residual = 2.29782e-06, No Iterations 3
DICPCG:  Solving for p, Initial residual = 0.981988, Final residual = 8.49443e-07, No Iterations 293
time step continuity errors : sum local = 1.21941e-09, global = 2.49295e-12, cumulative = 4.74924e-12
DILUPBiCG:  Solving for nuTilda, Initial residual = 0.000310185, Final residual = 9.04832e-06, No Iterations 1
bounding nuTilda, min: -0.402278 max: 67.8727 average: 0.0384613
ExecutionTime = 28.24 s  ClockTime = 28 s

Courant Number mean: 0.11094 max: 21.5535
#0  Foam::error::printStack(Foam::Ostream&) in "/home/greg/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/libOpenFOAM.so"
#1  Foam::sigFpe::sigFpeHandler(int) in "/home/greg/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/libOpenFOAM.so"
#2  Uninterpreted: 
#3  Foam::Time::adjustDeltaT() in "/home/greg/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/libOpenFOAM.so"
#4  Foam::Time::setDeltaT(double) in "/home/greg/OpenFOAM/OpenFOAM-1.6.x/lib/linuxGccDPOpt/libOpenFOAM.so"
#5  main in "/home/greg/OpenFOAM/OpenFOAM-1.6.x/applications/bin/linuxGccDPOpt/pimpleDyMFoam"
#6  __libc_start_main in "/lib/tls/i686/cmov/libc.so.6"
#7  _start at /build/buildd/eglibc-2.10.1/csu/../sysdeps/i386/elf/start.S:122
Floating point exception

I have experimented with PIMPLE settings, and under-relaxation. My current settings in fvSolution are:

PIMPLE
{
    nOuterCorrectors 2;
    nCorrectors     1;
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       0;
}


relaxationFactors
{
    U               0.7;
    p               0.2;
    nuTilda         0.7;
}

And my fvSchemes:

ddtSchemes
{
    default Euler;
}

gradSchemes
{
    default         Gauss linear;
    grad(p)         Gauss linear;
    grad(U)         Gauss linear;
}

divSchemes
{
    default         Gauss QUICK phi;
//    div(phi,U)      Gauss limitedLinear 1;
    div(phi,U)      Gauss upwind;
    div(phi,k)      Gauss limitedLinear 1;
    div(phi,epsilon) Gauss limitedLinear 1;
    div(phi,R)      Gauss limitedLinear 1;
    div(R)          Gauss linear;
    div(phi,nuTilda) Gauss limitedLinear 1;
    div((nuEff*dev(grad(U).T()))) Gauss linear;
}

laplacianSchemes
{
    default         none;
    laplacian(nu,U) Gauss linear corrected;
    laplacian(nuEff,U) Gauss linear corrected;
    laplacian((1|A(U)),p) Gauss linear corrected;
    laplacian(DkEff,k) Gauss linear corrected;
    laplacian(DepsilonEff,epsilon) Gauss linear corrected;
    laplacian(DREff,R) Gauss linear corrected;
    laplacian(DnuTildaEff,nuTilda) Gauss linear corrected;
    laplacian(rAU,pcorr) Gauss linear corrected;
    laplacian(rAU,p) Gauss linear corrected;
}

interpolationSchemes
{
    default         linear;
    interpolate(U)  linear;
}

snGradSchemes
{
    default         corrected;
}

fluxRequired
{
    default         no;
    p;
}

I'd appreciate any hints.


-Greg

[TReviol]

Hi Greg,

try to run "unset FOAM_SIGFPE" in the commandline, before you run your job.

Regards

Thomas

[jferrari]

Greg,

Were you able to get this working? Would you mind posting your dynamic mesh dictionary? I'm interested in seeing it.

Thanks,
Joe

[gfilip]

Hi Thomas and Joe,

I was able to get the case working but it has been a while. Unfortunately I had a different workstation at that time and those case setups have not made the move, so I am unable to share the dynamic mesh dict with you. Sorry!


Greg

[ebah6]

Hey gfillip,

I understand you no longer have the data, but do you remember a bit of what you did to solve the problem. I am running into similar difficulties where the Courant number keeps increasing until the job crashes.
Here are my few lines of my log file:
--------------------------------

Courant Number mean: 0.0553216 max: 1.49585
deltaT = 1e-05
Time = 7e-05

solidBodyMotionFunctions::rotatingMotion::transfor mation(): Time = 7e-05 transformation: ((0 0 0) (1 (0 0 0.00071295)))
AMI: Creating addressing and weights between 152 source faces and 152 target faces
AMI: Patch source weights min/max/average = 1.00045, 1.00059, 1.00051
AMI: Patch target weights min/max/average = 1.00027, 1.00041, 1.00034
PIMPLE: iteration 1
smoothSolver: Solving for Ux, Initial residual = 0.821499, Final residual = 0.0529954, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.772528, Final residual = 0.0435714, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.889394, Final residual = 0.0573016, No Iterations 3
GAMG: Solving for p, Initial residual = 0.927555, Final residual = 0.00793319, No Iterations 3
time step continuity errors : sum local = 0.00232858, global = 1.09112e-05, cumulative = 4.39653e-05
PIMPLE: iteration 2
smoothSolver: Solving for Ux, Initial residual = 0.624835, Final residual = 0.0579445, No Iterations 8
smoothSolver: Solving for Uy, Initial residual = 0.528869, Final residual = 0.0500303, No Iterations 7
smoothSolver: Solving for Uz, Initial residual = 0.667562, Final residual = 0.0371676, No Iterations 4
GAMG: Solving for p, Initial residual = 0.921425, Final residual = 0.00829498, No Iterations 2
time step continuity errors : sum local = 0.0183302, global = 0.000417751, cumulative = 0.000461716
PIMPLE: iteration 3
DILUPBiCG: Solving for Ux, Initial residual = 0.469402, Final residual = 0.00155559, No Iterations 1001
DILUPBiCG: Solving for Uy, Initial residual = 0.456055, Final residual = 0.00192389, No Iterations 1001
DILUPBiCG: Solving for Uz, Initial residual = 0.657918, Final residual = 7.2394e-07, No Iterations 26
GAMG: Solving for p, Initial residual = 0.940662, Final residual = 9.79822e-07, No Iterations 23
time step continuity errors : sum local = 5.83896e-06, global = -5.30525e-07, cumulative = 0.000461185
DILUPBiCG: Solving for epsilon, Initial residual = 0.989478, Final residual = 10537.6, No Iterations 1001
bounding epsilon, min: -1.28949e+18 max: 9.22403e+17 average: -3.22331e+14
DILUPBiCG: Solving for k, Initial residual = 1.42853e-05, Final residual = 6.87541e-07, No Iterations 30
bounding k, min: -1.84393e+10 max: 2.85172e+12 average: 1.06974e+10
ExecutionTime = 12.17 s ClockTime = 13 s

forces output:
forces(pressure, viscous)((-2.16039e+11 -1.76242e+12 2.33002e+07) (-4.46086e+07 -2.83529e+08 5.60693e+07))
moment(pressure, viscous)((-7.72514e+11 9.4704e+10 4.1255e+10) (-9.58347e+07 1.70477e+07 1.15609e+07))

Courant Number mean: 4.69634 max: 8810.84
deltaT = 2.26963e-09
Time = 7.00023e-05

solidBodyMotionFunctions::rotatingMotion::transfor mation(): Time = 7.00023e-05 transformation: ((0 0 -8.67362e-19) (1 (0 0 0.000712973)))
AMI: Creating addressing and weights between 152 source faces and 152 target faces
AMI: Patch source weights min/max/average = 1.00045, 1.00059, 1.00051
AMI: Patch target weights min/max/average = 1.00027, 1.00041, 1.00034
PIMPLE: iteration 1
smoothSolver: Solving for Ux, Initial residual = 0.924264, Final residual = 0.0530127, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.641598, Final residual = 0.0386788, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.921792, Final residual = 0.0461483, No Iterations 2
GAMG: Solving for p, Initial residual = 1, Final residual = 5705.13, No Iterations 50
time step continuity errors : sum local = 9.40062e+08, global = 3.78949e+07, cumulative = 3.78949e+07
PIMPLE: iteration 2
smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.0224152, No Iterations 1
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0293676, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.00299007, Final residual = 6.31039e-05, No Iterations 1
GAMG: Solving for p, Initial residual = 0.595319, Final residual = 9.86458e-05, No Iterations 1
time step continuity errors : sum local = 3.27194e+16, global = 4.33629e+15, cumulative = 4.33629e+15
PIMPLE: iteration 3
DILUPBiCG: Solving for Ux, Initial residual = 0.999996, Final residual = 5.86893e-07, No Iterations 28
DILUPBiCG: Solving for Uy, Initial residual = 0.999998, Final residual = 7.80082e-07, No Iterations 20
DILUPBiCG: Solving for Uz, Initial residual = 0.000201204, Final residual = 9.98882e-07, No Iterations 5
GAMG: Solving for p, Initial residual = 0.879029, Final residual = 7.05858e-07, No Iterations 47
time step continuity errors : sum local = 4.76118e+19, global = -8.01772e+18, cumulative = -8.01339e+18
DILUPBiCG: Solving for epsilon, Initial residual = 1, Final residual = 48876.6, No Iterations 1001
bounding epsilon, min: -1.7324e+51 max: 2.47572e+51 average: 5.46302e+48
DILUPBiCG: Solving for k, Initial residual = 1, Final residual = 6.79817e-07, No Iterations 96
bounding k, min: -1.36796e+48 max: 7.09554e+59 average: 6.62561e+56
ExecutionTime = 15.72 s ClockTime = 16 s

forces output:
forces(pressure, viscous)((5.96091e+57 4.44151e+57 3.98466e+52) (3.53788e+57 -2.92522e+58 1.66546e+57))
moment(pressure, viscous)((2.01323e+57 -2.60251e+57 -1.10323e+57) (-1.21739e+58 -1.87448e+57 -3.42054e+57))

Courant Number mean: 2.99449e+25 max: 3.21959e+28
deltaT = 1.40989e-37
--> FOAM Warning :
From function Time:perator++()
in file db/Time/Time.C at line 1010
Increased the timePrecision from 6 to 7 to distinguish between timeNames at time 7.00023e-05
Time = 7.000227e-05

solidBodyMotionFunctions::rotatingMotion::transfor mation(): Time = 7.00023e-05 transformation: ((0 0 -8.67362e-19) (1 (0 0 0.000712973)))
AMI: Creating addressing and weights between 152 source faces and 152 target faces
AMI: Patch source weights min/max/average = 1.00045, 1.00059, 1.00051
AMI: Patch target weights min/max/average = 1.00027, 1.00041, 1.00034
PIMPLE: iteration 1
smoothSolver: Solving for Ux, Initial residual = 0.904795, Final residual = 0.0198399, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.920089, Final residual = 0.00357272, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.770617, Final residual = 0.0112283, No Iterations 1
GAMG: Solving for p, Initial residual = 1, Final residual = 3.34459e+74, No Iterations 50
time step continuity errors : sum local = 2.15853e+83, global = 2.27242e+82, cumulative = 2.27242e+82
PIMPLE: iteration 2
smoothSolver: Solving for Ux, Initial residual = 0.998805, Final residual = 1.80506, No Iterations 1000
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 1.93583e-05, No Iterations 1
smoothSolver: Solving for Uz, Initial residual = 0.000531627, Final residual = 1.42642e-07, No Iterations 1
#0 Foam::error:rintStack(Foam::Ostream&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#1 Foam::sigFpe::sigHandler(int) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#2 in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam:ICPreconditioner::calcReciprocalD(Foam::Fie ld<double>&, Foam::lduMatrix const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#4 Foam:ICSmoother:ICSmoother(Foam::word const&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#5 Foam:ICGaussSeidelSmoother:ICGaussSeidelSmooth er(Foam::word const&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#6 Foam::lduMatrix::smoother::addsymMatrixConstructor ToTable<Foam:ICGaussSeidelSmoother>::New(Foam::w ord const&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#7 Foam::lduMatrix::smoother::New(Foam::word const&, Foam::lduMatrix const&, Foam::FieldField<Foam::Field, double> const&, Foam::FieldField<Foam::Field, double> const&, Foam::UPtrList<Foam::lduInterfaceField const> const&, Foam::dictionary const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#8 Foam::GAMGSolver::initVcycle(Foam::PtrList<Foam::F ield<double> >&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::lduMatrix::smoother>&) const in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#9 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libOpenFOAM.so"
#10 Foam::fvMatrix<double>::solve(Foam::dictionary const&) in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/lib/libfiniteVolume.so"
#11
in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/bin/pimpleDyMFoam"
#12 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#13
in "/home/alpha/OpenFOAM/OpenFOAM-2.1.x/platforms/linux64GccDPOpt/bin/pimpleDyMFoam"
Floating point exception

------------------------------------

If any one has a hint, please it welcome.

I checked the boundary conditions but it doesn't seem to come from there for they are very similar to those of the propeller example.

Thank all and best regards.

[Attesz]

Your k and omega is blowing up, i would have a look on them first. Try underrelaxation, especially for omega, and decrease the absolute tolerance to 1e-12 by setting the relTol to 0. Also have a look on the yplus and your wall modelling approach (if yplus is too small, forcing wallFunctions can cause blowing up the k and omega)

[dogan]

Hi all,

i am working on a transient pump simulation, and i am getting a floating point exception. My geometry has a rotating part and a stationary part and between them, i have two cyclicGgi interfaces. I am using OF1.6 ext, and pimpleDyMFoam as the solver. My simulation starts to run, it runs until for a while, then it crashes with the floating point exception error message. I have tried almost everything, but i couldn't solve the problem. Now i am worried about that if i am doing something wrong about the mesh manipulating steps. or in general, can someone summarize me which steps do i have to follow before i start with the transient simulation?

thanks in advance

Dogan