[logan.unser]

Hey Foamers,

I posted yesterday but didn't get a response. I hope I can get some help if I give a fuller picture of the issue. I am running OpenFOAM8 on windows through the Windows Subsystem for Linux. I want to simulate natural convection in a pipe like so:



(Sorry about my horrible paint skills)

I created a mesh using gmsh and imported it as a polyMesh using gambitToFoam. checkMesh runs just fine, and I have set up the boundary conditions using the buoyantCavity tutorial as a guide. Unfortunately, when I run buoyantSimpleFoam, it will stop after the first timestep and output:

/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
Build  : 8-1c9b5879390b
Exec   : buoyantSimpleFoam
Date   : Apr 14 2021
Time   : 16:33:54
Host   : "LJU-Desktop"
PID    : 32164
I/O    : uncollated
Case   : /home/logan/OpenFOAM/logan-8/run/buoyantPipe
nProcs : 1
sigFpe : Enabling floating point exception trapping (FOAM_SIGFPE).
fileModificationChecking : Monitoring run-time modified files using timeStampMaster (fileModificationSkew 10)
allowSystemOperations : Allowing user-supplied system call operations

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

Create mesh for time = 0


SIMPLE: Convergence criteria found
        p_rgh: tolerance 0.0001
        U: tolerance 0.0001
        h: tolerance 0.0001
        "(k|epsilon|omega)": tolerance 0.001

Reading thermophysical properties

Selecting thermodynamics package 
{
    type            heRhoThermo;
    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 turbulence model type RAS
Selecting RAS turbulence model kOmegaSST
Selecting patchDistMethod meshWave
RAS
{
    model           kOmegaSST;
    turbulence      on;
    printCoeffs     on;
    alphaK1         0.85;
    alphaK2         1;
    alphaOmega1     0.5;
    alphaOmega2     0.856;
    gamma1          0.555556;
    gamma2          0.44;
    beta1           0.075;
    beta2           0.0828;
    betaStar        0.09;
    a1              0.31;
    b1              1;
    c1              10;
    F3              false;
}

Creating thermophysical transport model

Selecting thermophysical transport type RAS
Selecting default RAS thermophysical transport model eddyDiffusivity

Reading g

Reading hRef
Calculating field g.h


Reading pRef
Reading field p_rgh

No MRF models present

Radiation model not active: radiationProperties not found
Selecting radiationModel none
No finite volume options present

Starting time loop

Time = 0.01

DILUPBiCGStab:  Solving for h, Initial residual = 1, Final residual = 0.0119179, No Iterations 1
GAMG:  Solving for p_rgh, Initial residual = 0.941951, Final residual = 0.00615762, No Iterations 2
time step continuity errors : sum local = 0.0410995, global = 8.06205e-18, cumulative = 8.06205e-18
DILUPBiCGStab:  Solving for omega, Initial residual = 0.536154, Final residual = 0.00486674, No Iterations 1
bounding omega, min: -0.084306 max: 10.2604 average: 0.214603
DILUPBiCGStab:  Solving for k, Initial residual = 1, Final residual = 0.0127145, No Iterations 1
ExecutionTime = 0.15 s  ClockTime = 0 s

Time = 0.02

DILUPBiCGStab:  Solving for h, Initial residual = 0.9075, Final residual = 0.0138294, No Iterations 1

controlDict:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     buoyantSimpleFoam;

startFrom       startTime;

startTime       0;

stopAt          endTime;

endTime         10;

deltaT          .01;

writeControl    timeStep;

writeInterval   1;

purgeWrite      3;

writeFormat     ascii;

writePrecision  6;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;


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

fvSchemes:

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default steadyState;
}

gradSchemes
{
    default         Gauss linear;
}

divSchemes
{
    default         none;

    div(phi,U)      bounded Gauss limitedLinear 0.2;
    div(phi,K)      bounded Gauss limitedLinear 0.2;
    div(phi,h)      bounded Gauss limitedLinear 0.2;
    div(phi,k)      bounded Gauss limitedLinear 0.2;
    div(phi,epsilon) bounded Gauss limitedLinear 0.2;
    div(phi,omega) bounded Gauss limitedLinear 0.2;
    div(((rho*nuEff)*dev2(T(grad(U))))) Gauss linear;
}

laplacianSchemes
{
    default         Gauss linear orthogonal;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         orthogonal;
}

wallDist
{
    method meshWave;
}


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

fvSolution

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  8
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    p_rgh
    {
        solver           GAMG;
        tolerance        1e-7;
        relTol           0.01;

        smoother         DICGaussSeidel;

    }

    "(U|h|k|epsilon|omega)"
    {
        solver          PBiCGStab;
        preconditioner  DILU;
        tolerance       1e-8;
        relTol          0.1;
    }
}

SIMPLE
{
    momentumPredictor no;
    nNonOrthogonalCorrectors 0;
    pRefCell        0;
    pRefValue       0;

    residualControl
    {
        p_rgh           1e-4;
        U               1e-4;
        h               1e-4;

        // possibly check turbulence fields
        "(k|epsilon|omega)" 1e-3;
    }
}

relaxationFactors
{
    fields
    {
        rho             1.0;
        p_rgh           0.7;
    }
    equations
    {
        U               0.3;
        h               0.3;
        "(k|epsilon|omega)" 0.7;
    }
}


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

If there is anything else you need, please ask! I have been really struggling with getting this to work!

[justAnIntern]

Your fvSchemes are in orthogonal mode. This only works well with pure blockMesh. Your mesh looks very tet to me. Try laplacian " default Gauss linear uncorrected;" and snGradSchemes " default uncorrected;" maybe? Probably also not ideal but better as it is just straight stolen from another tutorial.

[logan.unser]

It is still stopping after the first timestep, but I'm sure it would have become a pain later, so thanks!