[Mirage12]

i do not really want to a final steady-state solution, that is why i am trying a transient solver .

but nimasam suggested, that i can use simpleFoam for for laminar flow, that is why i try to add the temperature in the simpleFoam solver.

[Alfalfa]

Hello everyone, I also have a problem with my courant number.

In order to practice with OpenFOAM (since I'm a beginner), I tried to create a simple nozzle with blockMesh. To run the case, I use the elbow simulation with icoFoam. I changed the meshing to use the one I created and run blockMesh. but when I run the simulation, I get courant number of the magintue e289 on the very first step... I tried a coarse meshing, but nothing changed, I tried really small time step, still nothing and now I don't know what to do .

Here is my meshing:

convertToMeters 0.1;

vertices
(
    (-25 0 0.5)        //0
    (0 -10 0.5)        //1
    (0 10 0.5)        //2
    (-25 5 0.5)        //3
    (-25 0 -0.5)    //4
    (0 -10 -0.5)    //5
    (0 10 -0.5)        //6
    (-25 5 -0.5)    //7


    
);

blocks
(
    hex (0 1 2 3 4 5 6 7) (25 25 1) simpleGrading (1 1 1)

);

edges
(
);

boundary
(
    inlet
    {
        type patch;
        faces
        (
            (0 3 7 4)
        );
    }
    outlet
    {
        type patch;
        faces
        (
        (1 2 6 5)
        );
    }
    upperWall
    {
        type wall;
        faces
        (
            (3 2 6 7)
        );
    }
    lowerWall
    {
        type wall;
        faces
        (
            (0 1 5 4)
        );
    }
    frontAndBack
    {
        type empty;
        faces
        (
            (0 1 2 3)
            (4 5 6 7)
        );
    }
);

mergePatchPairs
(
);

Here's the controlDict :

application     icoFoam;

startFrom       latestTime;

startTime       0;

stopAt          endTime;

endTime         0.1;

deltaT          0.001;

writeControl    timeStep;

writeInterval   20;

purgeWrite      0;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;

I run OpenFOAM 2.2.0 on Ubuntu 12.04 LTS.

Any help would be appreciated. I try to learn OpenFoam by modifying the tutorial and this is my first (pathetic) attempt.

Thanks

[Alfalfa]

Oh nevermind, I found my error using checkMesh . My mesh orientation was not good.

[shaggadude]

Hello Foamers,
I am new to openfoam.I have created my own solver adding temperature equation (only advection-diffusion with velocity) to the icoFoam solver. to be specific ,code is
solve
( fvm::div(phi,T)
- fvm::laplacian(DT,T)
);
I am getting this error

Courant Number mean: 0.0248669 max: 2.20364
smoothSolver: Solving for Ux, Initial residual = 0.202777, Final residual = 1.21499e+270, No Iterations 1000
smoothSolver: Solving for Uy, Initial residual = 0.351417, Final residual = 8.3534e+269, No Iterations 1000
DILUPBiCG: Solving for T, Initial residual = 0.00762719, Final residual = 8.13923e-06, No Iterations 23
#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 double Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4 Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#5 Foam::GAMGSolver::solveCoarsestLevel(Foam::Field<d ouble>&, Foam::Field<double> const&) const at ??:?
#6 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMa trix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
#7 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#8 Foam::fvMatrix<double>::solveSegregated(Foam::dict ionary const&) at ??:?
#9 Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
#10 ? at ??:?
#11 ? at ??:?
#12 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#13 ? at ??:?
Floating point exception (core dumped)

After some debugging I fund out that lowering value of nu to 0.01 I am getting the output but as I lower the values to 0.001 it starts giving this output.I want to simulate it with nu=1e^-6 .What is wrong with this?I am attaching the files of the fvsolution,geometry etc.

[MehdiCFD]

helo everyone i have the same probleme, i would like to simulate an airflow around an airfoil i used rhosimplefoam like a solver and when i'm compiling its apear this message:
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 3.0.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 3.0.1-d8a290b55d28
Exec : rhoSimpleFoam
Date : Apr 19 2016
Time : 15:10:30
Host : "mehdi-HP-250-G4-Notebook-PC"
PID : 7408
Case : /home/mehdi/OpenFOAM/mehdi-3.0.1/run/airfoil/airfoil_rhoSimpleFoam
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster
allowSystemOperations : Allowing user-supplied system call operations

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
Create time

Create mesh for time = 0


SIMPLE: convergence criteria
field p tolerance 0.01
field U tolerance 0.0001
field e tolerance 0.001
field "(k|epsilon|omega)" tolerance 0.001

Reading thermophysical properties

Selecting thermodynamics package
{
type hePsiThermo;
mixture pureMixture;
transport const;
thermo hConst;
equationOfState perfectGas;
specie specie;
energy sensibleEnthalpy;
}

Reading field U

Reading/calculating face flux field phi

Creating turbulence model

Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
C3 -0.33;
sigmak 1;
sigmaEps 1.3;
}

#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/home/mehdi/OpenFOAM/OpenFOAM-3.0.1/platforms/linuxGccDPInt32Opt/lib/libOpenFOAM.so"
#3 Foam::divide(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4 Foam:perator/(Foam::tmp<Foam::Field<double> > const&, Foam::tmp<Foam::Field<double> > const&) at ??:?
#5 Foam::fluidThermo::nu(int) const at ??:?
#6 Foam::TurbulenceModel<Foam::geometricOneField, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>, Foam::compressibleTurbulenceModel, Foam::fluidThermo>::nu(int) const at ??:?
#7 Foam::nutkWallFunctionFvPatchScalarField::calcNut( ) const at ??:?
#8 Foam::nutWallFunctionFvPatchScalarField::updateCoe ffs() at ??:?
#9 Foam::fvPatchField<double>::evaluate(Foam::UPstrea m::commsTypes) at ??:?
#10 Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>::GeometricBoundaryField::evaluate() at ??:?
#11 Foam::RASModels::kEpsilon<Foam::EddyDiffusivity<Fo am::ThermalDiffusivity<Foam::CompressibleTurbulenc eModel<Foam::fluidThermo> > > >::correctNut() at ??:?
#12 Foam::RASModels::kEpsilon<Foam::EddyDiffusivity<Fo am::ThermalDiffusivity<Foam::CompressibleTurbulenc eModel<Foam::fluidThermo> > > >::kEpsilon(Foam::geometricOneField const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::fluidThermo const&, Foam::word const&, Foam::word const&) at ??:?
#13 Foam::RASModel<Foam::EddyDiffusivity<Foam::Thermal Diffusivity<Foam::CompressibleTurbulenceModel<Foam ::fluidThermo> > > >::adddictionaryConstructorToTable<Foam::RASModels ::kEpsilon<Foam::EddyDiffusivity<Foam::ThermalDiff usivity<Foam::CompressibleTurbulenceModel<Foam::fl uidThermo> > > > >::New(Foam::geometricOneField const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::fluidThermo const&, Foam::word const&) at ??:?
#14 Foam::RASModel<Foam::EddyDiffusivity<Foam::Thermal Diffusivity<Foam::CompressibleTurbulenceModel<Foam ::fluidThermo> > > >::New(Foam::geometricOneField const&, Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<Foam::Vector<double>, Foam::fvPatchField, Foam::volMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::GeometricField<double, Foam::fvsPatchField, Foam::surfaceMesh> const&, Foam::fluidThermo const&, Foam::word const&) at ??:?
#15 ? at ??:?
#16 __libc_start_main in "/lib/i386-linux-gnu/libc.so.6"
#17 ? at ??:?
Exception en point flottant (core dumped)
mehdi@mehdi-HP-250-G4-Notebook-PC:~/OpenFOAM/mehdi-3.0.1/run/airfoil/airfoil_rhoSimpleFoam$
if someone can help me please it's for my master project, thank you

[immortality]

Originally Posted by shaggadude

Hello Foamers,
I am new to openfoam.I have created my own solver adding temperature equation (only advection-diffusion with velocity) to the icoFoam solver. to be specific ,code is
solve
( fvm::div(phi,T)
- fvm::laplacian(DT,T)
);
I am getting this error

Courant Number mean: 0.0248669 max: 2.20364
smoothSolver: Solving for Ux, Initial residual = 0.202777, Final residual = 1.21499e+270, No Iterations 1000
smoothSolver: Solving for Uy, Initial residual = 0.351417, Final residual = 8.3534e+269, No Iterations 1000
DILUPBiCG: Solving for T, Initial residual = 0.00762719, Final residual = 8.13923e-06, No Iterations 23
#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 double Foam::sumProd<double>(Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4 Foam::PCG::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#5 Foam::GAMGSolver::solveCoarsestLevel(Foam::Field<d ouble>&, Foam::Field<double> const&) const at ??:?
#6 Foam::GAMGSolver::Vcycle(Foam::PtrList<Foam::lduMa trix::smoother> const&, Foam::Field<double>&, Foam::Field<double> const&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::Field<double>&, Foam::PtrList<Foam::Field<double> >&, Foam::PtrList<Foam::Field<double> >&, unsigned char) const at ??:?
#7 Foam::GAMGSolver::solve(Foam::Field<double>&, Foam::Field<double> const&, unsigned char) const at ??:?
#8 Foam::fvMatrix<double>::solveSegregated(Foam::dict ionary const&) at ??:?
#9 Foam::fvMatrix<double>::solve(Foam::dictionary const&) at ??:?
#10 ? at ??:?
#11 ? at ??:?
#12 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#13 ? at ??:?
Floating point exception (core dumped)

After some debugging I fund out that lowering value of nu to 0.01 I am getting the output but as I lower the values to 0.001 it starts giving this output.I want to simulate it with nu=1e^-6 .What is wrong with this?I am attaching the files of the fvsolution,geometry etc.

Hi
your courant number seems too high.may it cause the run to be unstable. reduce it to be lower than 1 by lowering time step. may it be solved.

[Mdong]

Hello everyone,
I am a newer, and why this error occurs in OpenFoam?

This is the code.
Time = 1600

pseudoTime: iteration 1600
Pseudo Courant No: Min: 0.10078836 Mean: 8.467278 Max: 9.5664346
Pseudo deltaT: Min: 1.6848402e-05 Mean: 0.0054943401 Max: 0.067294106
Solving for (rho rhoU rhoE)
GMRES iteration: 0 Residual: 0.0049290487 (0.003904797 0.0052534381 0.0039910031) 0.004746403
GMRES iteration: 1 Residual: 1.1723583e-06 (7.1752593e-07 7.1192873e-07 5.6116024e-07) 9.8950704e-07
ExecutionTime = 2340.76 s ExecutionStepTime = 1.68 s ClockTime = 2341 s

min/max/integ(body) = -12910.768, -1033.1014, -1.6392455e+08
min/max/integ(farfield) = 0, 0, 0
wallHeatFlux wallHeatFlux write:
writing field wallHeatFlux
yPlus yPlus write:
writing field yPlus
[timothy-Super-Server:16007] *** Process received signal ***
[timothy-Super-Server:16007] Signal: Floating point exception (8)
[timothy-Super-Server:16007] Signal code: (-6)
[timothy-Super-Server:16007] Failing at address: 0x3e900003e87
[timothy-Super-Server:16007] [ 0] /lib/x86_64-linux-gnu/libpthread.so.0(+0x128a0)[0x1482479bc8a0]
[timothy-Super-Server:16007] [ 1] /lib/x86_64-linux-gnu/libpthread.so.0(raise+0xc7)[0x1482479bc737]
[timothy-Super-Server:16007] [ 2] /lib/x86_64-linux-gnu/libpthread.so.0(+0x128a0)[0x1482479bc8a0]
[timothy-Super-Server:16007] [ 3] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERNS_5FieldIdEERKNS_5U ListIdEE+0x30)[0x148248f0ce80]
[timothy-Super-Server:16007] [ 4] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERKNS_3tmpINS_5FieldId EEEE+0x51)[0x148248f15e41]
[timothy-Super-Server:16007] [ 5] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libfieldFunctionObjects.so(_ZN4Foam15functionObjec ts5yPlus7executeEv+0x31b)[0x148221d5747b]
[timothy-Super-Server:16007] [ 6] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam15functionObjects11timeCont rol7executeEv+0x54)[0x148248c9b154]
[timothy-Super-Server:16007] [ 7] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam18functionObjectList7execut eEv+0x108)[0x148248c8c118]
[timothy-Super-Server:16007] [ 8] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam4Time3runEv+0x21d)[0x148248ca5d4d]
[timothy-Super-Server:16007] [ 9] hisa(+0x3cbc)[0x556972d69cbc]
[timothy-Super-Server:16007] [10] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x1482475dab97]
[timothy-Super-Server:16007] [11] hisa(+0x4b4a)[0x556972d6ab4a]
[timothy-Super-Server:16007] *** End of error message ***
[timothy-Super-Server:16006] *** Process received signal ***
[timothy-Super-Server:16006] Signal: Floating point exception (8)
[timothy-Super-Server:16006] Signal code: (-6)
[timothy-Super-Server:16006] Failing at address: 0x3e900003e86
[timothy-Super-Server:16006] [ 0] /lib/x86_64-linux-gnu/libpthread.so.0(+0x128a0)[0x154a597bd8a0]
[timothy-Super-Server:16006] [ 1] /lib/x86_64-linux-gnu/libpthread.so.0(raise+0xc7)[0x154a597bd737]
[timothy-Super-Server:16006] [ 2] /lib/x86_64-linux-gnu/libpthread.so.0(+0x128a0)[0x154a597bd8a0]
[timothy-Super-Server:16006] [ 3] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERNS_5FieldIdEERKNS_5U ListIdEE+0x30)[0x154a5ad0de80]
[timothy-Super-Server:16006] [ 4] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam4sqrtERKNS_3tmpINS_5FieldId EEEE+0x51)[0x154a5ad16e41]
[timothy-Super-Server:16006] [ 5] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libfieldFunctionObjects.so(_ZN4Foam15functionObjec ts5yPlus7executeEv+0x31b)[0x154a33d4147b]
[timothy-Super-Server:16006] [ 6] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam15functionObjects11timeCont rol7executeEv+0x54)[0x154a5aa9c154]
[timothy-Super-Server:16006] [ 7] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZN4Foam18functionObjectList7execut eEv+0x108)[0x154a5aa8d118]
[timothy-Super-Server:16006] [ 8] /home/ubuntu/OpenFOAM/OpenFOAM-v2006/platforms/linux64GccDPInt32Opt/lib/libOpenFOAM.so(_ZNK4Foam4Time3runEv+0x21d)[0x154a5aaa6d4d]
[timothy-Super-Server:16006] [ 9] hisa(+0x3cbc)[0x56239da75cbc]
[timothy-Super-Server:16006] [10] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xe7)[0x154a593dbb97]
[timothy-Super-Server:16006] [11] hisa(+0x4b4a)[0x56239da76b4a]
[timothy-Super-Server:16006] *** End of error message ***
--------------------------------------------------------------------------
mpirun noticed that process rank 3 with PID 0 on node timothy-Super-Server exited on signal 8 (Floating point exception).[/COLOR]