[PSander]

I calculate with OF8 and chtMultiRegionFoam. My geometry created with blockMesh is a simple square of x=6, y=3 and y=100 meters, thermophysical parameters are similar to sand.
The upper sirface has a constant heat flow of 303°K, the internal temperature is 293°K and all the other sides are of zero gradient.

My expectation is that after a certain time the whole block heated up to 303°K.

I run this model with steadyState, and I get what I expected.
I repeat it with Euler, and thought that the final results should be the same, but much slower.
But after a calculation of around 400.000 seconds the heating stops (not completly, but like 0.0000001°K per day), as you can see in the attached images.

1. Am I right that steadyState and Euler should have in the end the same result?
2. What could be my problem?

I suspect some setting in fvSolution or fvSchemes, so I attach the whole case and show you the code of those files.

Could you have a look and give me a hint? Thank you very much.


fvScheme for region soil

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSchemes;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

ddtSchemes
{
    default         Euler; // Euler steadyState
}

gradSchemes
{
    default         Gauss linear;
}

divSchemes
{
    default         none;
}

laplacianSchemes
{
    default             none;
    laplacian(alpha,e)  Gauss linear uncorrected;
}

interpolationSchemes
{
    default         linear;
}

snGradSchemes
{
    default         uncorrected;
}


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

fvSoultion for region soil

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

solvers
{
    e
    {
        solver           PCG;
        preconditioner   DIC;
        tolerance        1e-06;
        relTol           0.1;
    }

    eFinal
    {
        $e;
        tolerance        1e-06;
        relTol           0;
    }

}

PIMPLE
{
    nNonOrthogonalCorrectors 0;
    outerCorrectorResidualControl
    {
        e
        {
            tolerance 1e-5;
            relTol 0;
        }
    }
}

relaxationFactors
{
    equations
    {
        e           0.5;
        eFinal        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;
    location    "system";
    object      controlDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

application     chtMultiRegionFoam;

startFrom       latestTime;

startTime       0;

stopAt          endTime;

endTime         864000;

deltaT          1;

writeControl    adjustableRunTime;

writeInterval   3600;

purgeWrite      0;

writeFormat     ascii;

writePrecision  22;

writeCompression off;

timeFormat      general;

timePrecision   6;

runTimeModifiable true;

adjustTimeStep  true; 

maxCo           1;

functions
{

  #includeFunc "residuals_fluid"

  avT_fluid_outlet
  {
      type            surfaceFieldValue;
      libs            ("libfieldFunctionObjects.so");
      log             yes;
      writeControl    runTime;
      writeInterval   3600;	
      writeFields     false;
      surfaceFormat   none;
      regionType      patch;
      name            outlet;
      region 	      fluid;	
      operation       areaAverage;
      fields
      (
          T
      );
  }

  yPlus_fluid
  {
    type            yPlus;
    libs            ("libfieldFunctionObjects.so");
    executeControl  writeTime;
    writeControl    writeTime;
    region  fluid;
  } 

  wallHeatFlux_fluid
  {
    type            wallHeatFlux;
    libs            ("libfieldFunctionObjects.so");
    executeControl  writeTime;
    writeControl    writeTime;
    region  fluid;
  }

  wallShearStress_fluid
  {
    type            wallShearStress;
    libs            ("libfieldFunctionObjects.so");
    executeControl  writeTime;
    writeControl    writeTime;
    region  fluid;
  }

  turbulenceIntensity_fluid
  {
    type            turbulenceIntensity;
    libs            ("libfieldFunctionObjects.so");
    executeControl  writeTime;
    writeControl    writeTime;
    region  fluid;
  } 

}


libs (
"libOpenFOAM.so"
"libsimpleSwakFunctionObjects.so"
"libswakFunctionObjects.so"
"libgroovyBC.so"
);

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

general fvSolution

/*--------------------------------*- C++ -*----------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      fvSolution;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

PIMPLE
{
//    momentumPredictor yes;
    nOuterCorrectors 50;
    nCorrectors     2;
    nNonOrthogonalCorrectors 0;
    consistent      true;
    pRefCell        0;
    pRefValue       0;
}


// ************************************************************************* //average_temp_euler.JPG

average_temp_steadystate.JPG

test_01.zip