[Alisa_W]

Hello,everyone! I am a new learner of OpenFOAM. When I simulate pump by OpenFOAM, some divergence problems occurred and I have tried several methods but none worked.

Here is some of the solving information which includes the error I got:
simpleFoam
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 4.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
Build : 4.1
Exec : simpleFoam
Date : May 28 2017
Time : 12:16:54
Host : "wangying-HP-Pavilion-g6-Notebook-PC"
PID : 2306
Case : /home/wangying/OpenFOAM/wangying-4.1/0525pumpji
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: no convergence criteria found. Calculations will run for 500 steps.

Reading field p

Reading field U

Reading/calculating face flux field phi

Selecting incompressible transport model Newtonian
Selecting turbulence model type RAS
Selecting RAS turbulence model kEpsilon
kEpsilonCoeffs
{
Cmu 0.09;
C1 1.44;
C2 1.92;
alphaEps 0.76923;
C3 -0.33;
sigmak 1;
sigmaEps 1.3;
}

Creating MRF zone list from MRFProperties
creating MRF zone: MRF1
No finite volume options present


Starting time loop

Time = 1

smoothSolver: Solving for Ux, Initial residual = 1, Final residual = 0.0632162, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 1, Final residual = 0.0631513, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 1, Final residual = 0.0742623, No Iterations 2
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0237374, No Iterations 3
GAMG: Solving for p, Initial residual = 0.214527, Final residual = 0.00490524, No Iterations 2
GAMG: Solving for p, Initial residual = 0.0683111, Final residual = 0.00258945, No Iterations 2
time step continuity errors : sum local = 6.78421, global = 1.81365, cumulative = 1.81365
smoothSolver: Solving for epsilon, Initial residual = 0.999347, Final residual = 0.0580155, No Iterations 2
bounding epsilon, min: -466.105 max: 10663.5 average: 46.0336
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.0238778, No Iterations 2
bounding k, min: -59.6503 max: 211.429 average: 4.81273
ExecutionTime = 1.91 s ClockTime = 2 s

Time = 2

smoothSolver: Solving for Ux, Initial residual = 0.999829, Final residual = 0.0155857, No Iterations 4
smoothSolver: Solving for Uy, Initial residual = 0.999903, Final residual = 0.0136278, No Iterations 4
smoothSolver: Solving for Uz, Initial residual = 0.99998, Final residual = 0.0173314, No Iterations 4
GAMG: Solving for p, Initial residual = 1, Final residual = 0.0213176, No Iterations 2
GAMG: Solving for p, Initial residual = 0.172247, Final residual = 0.00236311, No Iterations 2
GAMG: Solving for p, Initial residual = 0.0370012, Final residual = 0.000739987, No Iterations 2
time step continuity errors : sum local = 3.68985e+13, global = 1.18867e+13, cumulative = 1.18867e+13
smoothSolver: Solving for epsilon, Initial residual = 1, Final residual = 0.00720723, No Iterations 4
bounding epsilon, min: -1.44295e+22 max: 7.00688e+22 average: 1.83296e+18
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.00869376, No Iterations 2
bounding k, min: -7.07964e+19 max: 9.1656e+20 average: 5.55772e+16
ExecutionTime = 2.93 s ClockTime = 3 s

Time = 3

smoothSolver: Solving for Ux, Initial residual = 0.965037, Final residual = 0.0400609, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.532929, Final residual = 0.0086271, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.867924, Final residual = 0.0293422, No Iterations 2
GAMG: Solving for p, Initial residual = 1, Final residual = 0.030117, No Iterations 3
GAMG: Solving for p, Initial residual = 2.24748e-08, Final residual = 2.30064e-09, No Iterations 1
GAMG: Solving for p, Initial residual = 4.21727e-07, Final residual = 9.44708e-09, No Iterations 2
time step continuity errors : sum local = 4.33021e+46, global = 2.34092e+45, cumulative = 2.34092e+45
smoothSolver: Solving for epsilon, Initial residual = 1, Final residual = 0.0157527, No Iterations 2
bounding epsilon, min: -1.4371e+70 max: 5.27114e+73 average: 6.07064e+68
smoothSolver: Solving for k, Initial residual = 1, Final residual = 0.017461, No Iterations 2
bounding k, min: -9.39586e+66 max: 4.74017e+67 average: 2.3506e+63
ExecutionTime = 3.89 s ClockTime = 4 s

Time = 4

smoothSolver: Solving for Ux, Initial residual = 0.47081, Final residual = 0.0176367, No Iterations 2
smoothSolver: Solving for Uy, Initial residual = 0.73317, Final residual = 0.0334041, No Iterations 2
smoothSolver: Solving for Uz, Initial residual = 0.472924, Final residual = 0.0147328, No Iterations 4
GAMG: Solving for p, Initial residual = 1, Final residual = 0.00771155, No Iterations 2
GAMG: Solving for p, Initial residual = 4.02407e-09, Final residual = 4.02407e-09, No Iterations 0
GAMG: Solving for p, Initial residual = 4.02407e-09, Final residual = 4.02407e-09, No Iterations 0
time step continuity errors : sum local = 2.28431e+122, global = -5.79654e+117, cumulative = -5.79654e+117
#0 Foam::error:rintStack(Foam::Ostream&) at ??:?
#1 Foam::sigFpe::sigHandler(int) at ??:?
#2 ? in "/lib/x86_64-linux-gnu/libc.so.6"
#3 Foam::multiply(Foam::Field<double>&, Foam::UList<double> const&, Foam::UList<double> const&) at ??:?
#4 Foam::tmp<Foam:imensionedField<double, Foam::volMesh> > Foamerator*<Foam::volMesh>(Foam:imensionedField< double, Foam::volMesh> const&, Foam::tmp<Foam:imensionedField<double, Foam::volMesh> > const&) at ??:?
#5 Foam::RASModels::kEpsilon<Foam::IncompressibleTurb ulenceModel<Foam::transportModel> >::correct() at ??:?
#6 ? at ??:?
#7 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#8 ? at ??:?
浮点数例外 (核心已转储)

I have thought that It was caused by some wrong setting in fvsolution and fvscheme files.I reset them but it seemed ineffective.
Can anyone give me any ideas? Thanks very much!!

[Alisa_W]

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
p
{
solver GAMG;
tolerance 1e-08;
relTol 0.05;
smoother GaussSeidel;
nCellsInCoarsestLevel 20;
}

U
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-07;
relTol 0.1;
}

k
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-07;
relTol 0.1;
}

epsilon
{
solver smoothSolver;
smoother GaussSeidel;
nSweeps 2;
tolerance 1e-07;
relTol 0.1;
}
}

SIMPLE
{
//nCorrectors 3;
nNonOrthogonalCorrectors 2;//0;
pRefCell 0;
pRefValue 0;
}

relaxationFactors
{
fields
{
p 0.3;
}
equations
{
U 0.7;
k 0.5;
epsilon 0.5;
}
}

[Alisa_W]

FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "system";
object fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
default Euler;//steadyState;
}

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

divSchemes
{
/*default none;
div(phi,U) bounded Gauss linearUpwind limited;
div(phi,k) bounded Gauss upwind;
div(phi,epsilon) bounded Gauss upwind;
div((nuEff*dev2(T(grad(U))))) Gauss linear;*/
default none;
div(phi,U) bounded Gauss limitedLinearV 1;
div(phi,k) bounded Gauss limitedLinear 1;
div(phi,epsilon) bounded Gauss limitedLinear 1;
div((nuEff*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
default Gauss linear corrected;
}

interpolationSchemes
{
default linear;
}

snGradSchemes
{
default corrected;
}
fluxRequired
{
default no;
p;
}

[piu58]

Dear Alisa,

it is hard for us to analyze what happens at your case. I recommend to check the boundary conditions and may be the mesh.

[Alisa_W]

Originally Posted by piu58

Dear Alisa,

it is hard for us to analyze what happens at your case. I recommend to check the boundary conditions and may be the mesh.

Thank you for your kind suggestion! I have done 'checkMesh' and the result seemed ok but is it the possible cause that the mesh I divided is so coarse that the quality of it can not meet some requirement?

[piu58]

Coarse meshes tend to unprecise results, but to fast convergence too. I thought more of real mistake in the mesh. Not all of them were found by checkMesh.

[Alisa_W]

Ok, I will see this mesh with ICEM and thank you very much for your suggestion!