[Kalabagh]

Hi Foamers,


I'm relatively new in OpenFoam, and I'm getting started with turbulence modelling.


My simulation consists on a stirred tank in where there is a vertical centered mixer. From the simulation I'm interested on the moments and forces for improving the tank design.


But I feel the turbulence produced by the mixed is not neglectable.


As I say in the title, after having improved the mesh, the solver keeps crashing at 6 to 9 timestep.


I just want to know what is happening and where I have to focus.


Here is the log:


...

Time = 9

smoothSolver: Solving for Ux, Initial residual = 5.05182e-20, Final residual = 5.05182e-20, No Iterations 0
smoothSolver: Solving for Uy, Initial residual = 1.54245e-17, Final residual = 1.54245e-17, No Iterations 0
smoothSolver: Solving for Uz, Initial residual = 4.36724e-21, Final residual = 4.36724e-21, No Iterations 0
GAMG: Solving for p, Initial residual = 4.53748e-08, Final residual = 4.53748e-08, No Iterations 0
time step continuity errors : sum local = 1.38557e+107, global = -2.33602e+91, cumulative = -2.33602e+91
#0 Foam::errorprintStack(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:dimensionedField<double, Foam::volMesh> > Foamoperator*<Foam::volMesh>(Foam:dimensionedField <double, Foam::volMesh> const&, Foam::tmp<Foam:dimensionedField<double, Foam::volMesh> > const&) at ??:?
#5 Foam::RASModels::kEpsilon<Foam::IncompressibleTurb ulenceModel<Foam::transportModel> >::correct() at ??:?
#6 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"
#7 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#8 ? in "/opt/openfoam5/platforms/linux64GccDPInt32Opt/bin/simpleFoam"


The number of iterations is low because I have reduced all the tolerances and relative tolerances in the fvSolution dict.


Thanks.

[Carlo_P]

First of all, try to us alwyas minIteration at least equal to 3.
Then, try to run laminar.
Then, change the relaxation factor at 0.5 for all.
Then, redoo the mesh.
Did you run checkMesh?


These are normal suggestions. If these don't solve the problem, try to attach the folder 0 and at least fvSchemes file.


Thanks,
Cheeres
Carlo

[Kalabagh]

I have tried laminar and it converges in 51 iterations "with permissible residual control".


I've tried with rel facts all to 0.5.


You can find attached a picture of my mesh. And also the log of the checkMesh. The mesh crashes, as this can bethe reason of not the best results in laminar, I don't think it to be the main problem.


You can also find attached U, p, nut, k, epsilon and fvSchemes. Maybe there is a problem with the configuration of turbulent parameters or with the divSchemes.


Thanks for your help.


Selección_028.png

checkMesh.txt


U:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volVectorField;
location "0";
object U;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
//- Set patchGroups for constraint patches

inlet
{
type noSlip;
}

outlet
{
type noSlip;
}

empty
{
type noSlip;
}

TURBINA
{
type noSlip;
}

REACTOR
{
type noSlip;
}

}


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


p:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object p;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0;

boundaryField
{
//- Set patchGroups for constraint patches

inlet
{
type zeroGradient;
}

outlet
{
type zeroGradient;
}

empty
{
type zeroGradient;
}

TURBINA
{
type zeroGradient;
}

REACTOR
{
type zeroGradient;
}

}

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


nut:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object nut;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -1 0 0 0 0];

internalField uniform 0;

boundaryField
{
//- Set patchGroups for constraint patches

inlet
{
type calculated;
value uniform 0;
}

outlet
{
type calculated;
value uniform 0;
}

empty
{
type zeroGradient;
}

TURBINA
{
type nutkWallFunction;
value uniform 0;
}

REACTOR
{
type nutkWallFunction;
value uniform 0;
}

}

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


k:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object k;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -2 0 0 0 0];

internalField uniform 0.227;

boundaryField
{
//- Set patchGroups for constraint patches

inlet
{
type fixedValue;
value uniform 0.227;
//no hi ha necessitat, no pertany a la malla final
}

outlet
{
type zeroGradient;
}

empty
{
type zeroGradient;
}

TURBINA
{
type kqRWallFunction;
value uniform 0.227;
}

REACTOR
{
type kqRWallFunction;
value uniform 0.227;
}

}

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


epsilon:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 5 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class volScalarField;
object epsilon;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 2 -3 0 0 0 0];

internalField uniform 0.376;

boundaryField
{
//- Set patchGroups for constraint patches

inlet
{
type fixedValue;
value uniform 0.376;
// no hi ha necessitat, no pertany a la malla final
}

outlet
{
type zeroGradient;
}

empty
{
type zeroGradient;
}

TURBINA
{
type epsilonWallFunction;
value uniform 0.376;
}

REACTOR
{
type epsilonWallFunction;
value uniform 0.376;
}

}

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