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steadyState - Euler - different endresults

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Old   January 30, 2021, 06:18
Default steadyState - Euler - different endresults
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I have problems to understand if my results do make sense or not.
I have the geometry of a square, x=6, y=3, z=100 meters. The upper surface works as a source of heat, where all the time 303K are streaming in. All the other sides are zero gradient, and the internal temperature is 293K. The thermophysical parameters are similar to sand. (kappa =2, Cv=1000, rho=2200)
I run with chtMultiRegionFoam and OF8.

Inside the square I have 2 tubes filles with water, but for this simulation the temperatures are as well 293K and the velocity is 0.

My expectacion is, that after a certain time everything should be heated up the surface temperature, since there is no other source of heat than the surface.

If I select steadyState exactly this happens, in the end everything is heated up to 303K.

If I repeat the same calculation with Euler, it takes around 5 days, while the square is constantly heating up from the upper surface, when the heating process seems to be stopping. Actually its not stopping completly, but the diference for the same cell between day 5 and day 10 is like 0.000001K, so almost nothing.
But the square is far away from having the upper surface temperature, in the lower regions it is still at 293K, the starting value.

So I expected, that steadyState and Euler produce in the end the same result, is this not true?

Because if it is true, than I dont know why my calculation is with Euler not coming to that point. There must be some problem in my settings?

Do you have any idea if
1. Euler and steadyState come to the same results or not?
2. If yes, what could be the problem in my settings?


I expect problems in the system-files, so I show you my fvSolution, fvSchemes and controlDict.


fvSolution for region soil:

Code:
/*--------------------------------*- 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;
    }
}

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

fvSchemes for region soil:
Code:
/*--------------------------------*- 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;
}


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


controlDict

Code:
/*--------------------------------*- 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
Code:
/*--------------------------------*- 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;
}


// ************************************************************************* //
Attached Files
File Type: zip test_01.zip (51.1 KB, 2 views)
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