[GuiMagyar]

Dear Foamers,

I'm kind of newbie on OpenFOAM and I got this incomprehensible problem which with i'm dealing with.

I have 4 stl files. One of this stl file is AirAmbiant (the air) and is surrounding all the other 3 stl files.
AirAmbiant is just a big hex which size is (50 470 160).

The problem is that i get this "region1" in zone "-1" (cf. the splitMeshRegions Log below) which is automatically created and i do not understand why ... because my blockmesh is exactly the size of my "AirAmbiant" stl file, so normally there should be no available space for the meshing to create this "region1" ?


I have tried several different meshing configuration but none has made this "region1" not to be generated...


Have you encountered this kind of issue or do you have any idea why it could occur ?

I have attached a screenshot of the generated "region 1" (in blue) which border is just inside blockmesh cells ... weird ?

Thank you very much for your help.

My blockmesh file, snappy file and splitMeshRegions log are below.

/*--------------------------------*- 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      blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

convertToMeters 0.001;

zmax 50;
//zmin -15;
ymax 470;
//ymin -135;
xmax 160;
//xmin -80;

vertices
(
    //parallèlipède de base pour le snappyMesh
        (0 0 0)
        ($xmax 0 0)
        ($xmax $ymax 0)
        (0 $ymax 0)
    (0 0 $zmax)
    ($xmax 0 $zmax)
        ($xmax $ymax $zmax)
    (0 $ymax $zmax)



          
);

blocks
(
    hex (0 1 2 3 4 5 6 7) (16 47 5) simpleGrading (1 5 3)
);

edges
(
);

boundary
(
        // Wall car pas d'échange avec l'extérieur (T°C imposée ou h infini)
    minZ
        {
            type wall;
            faces
            (
                    (1 0 3 2)
            );
    }
    maxZ
    {
        type wall;
        faces    ((4 5 6 7));
    }
    minX
    {
        type wall;
        faces    ((0 3 7 4));
    }
    maxX
    {
        type wall;
        faces    ((1 2 6 5));
    }
    minY
    {
        type patch;
        faces    ((0 1 5 4));
    }
    maxY
    {
        type patch;
        faces    ((3 2 6 7));
    }        
);

mergePatchPairs
(
);

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

SnappyHexMesh :

/*--------------------------------*- 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      snappyHexMeshDict;
}

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

// Which of the steps to run
castellatedMesh true;
snap            true;
addLayers       true;

geometry
{
    AirAmbiant
    {
        type triSurfaceMesh;
        file "AirAmbiant.stl";
    }

    TriacPlastique
    {
        type triSurfaceMesh;
        file "TriacPlastique.stl";
    }

    TriacAlu
    {
        type triSurfaceMesh;
        file "TriacAlu.stl";
    }    

    Dissipateur
    {
        type triSurfaceMesh;
        file "Dissipateur.stl";
    }
};

// Settings for the castellatedMesh generation.
castellatedMeshControls
{

    maxLocalCells 1000000;
    maxGlobalCells 2500000;
    minRefinementCells 0;
    nCellsBetweenLevels 1;

    //maxLoadUnbalance 0.00; 


    features
    (
        {
            file "AirAmbiant.eMesh";
            level 2;
        }
        {
            file "TriacAlu.eMesh";
            level 2;
        }
        {
            file "TriacPlastique.eMesh";
            level 2;
        }

        {
            file "Dissipateur.eMesh";
            level 3;
        }
     );



    // Surface based refinement
    refinementSurfaces
    {
        AirAmbiant
        {
            // Surface-wise min and max refinement level
            level (1 1);

            faceZone AirAmbiant; //pour marquer d'un flag les faces et cells à l'intérieur
            cellZone AirAmbiant;
            //cellZoneInside inside;
        }

         TriacPlastique
        {
            // Surface-wise min and max refinement level
            level (3 3);

            faceZone TriacPlastique;
            cellZone TriacPlastique;
            //cellZoneInside inside;
        }

        TriacAlu
        {
            // Surface-wise min and max refinement level
            level (3 3);

            faceZone TriacAlu;
            cellZone TriacAlu;
            //cellZoneInside inside;
        }

        Dissipateur
        {
            // Surface-wise min and max refinement level
            level (3 3);

            faceZone Dissipateur;
            cellZone Dissipateur;
            //cellZoneInside inside;
        }

    }

    // Resolve sharp angles
    resolveFeatureAngle 30;

    refinementRegions
    {
        // refinementBox
        //{
        //    mode inside;
        //    levels ((1E15 4));
        //}
    }


    // Mesh selection

    locationInMesh (0 0 0);
    allowFreeStandingZoneFaces false;
}



// Settings for the snapping.
snapControls
{

    nSmoothPatch 5;

    tolerance 1.0;

    nSolveIter 100;

    nRelaxIter 10;

    nFeatureSnapIter 5;
}



// Settings for the layer addition.
addLayersControls
{
    relativeSizes true;
    layers
    {
        Dissipateur_to_AirAmbiant
        {
            nSurfaceLayers 4;
        }
    }

    // Per final patch (so not geometry!) the layer information

    expansionRatio 1.2;
    finalLayerThickness 0.025;
    minThickness 0.005;
    nGrow 0;

    // Advanced settings

    featureAngle 30;

    nRelaxIter 3;

    nSmoothSurfaceNormals 2;

    nSmoothNormals 4;

    nSmoothThickness 2;

     maxFaceThicknessRatio 0.2;

    maxThicknessToMedialRatio 0.5;


    minMedianAxisAngle 90;

    nBufferCellsNoExtrude 0;

    nLayerIter 50;
}


meshQualityControls
{
    #include "meshQualityDict"
}


mergeTolerance 1e-6;


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

splitMeshRegions Log :

--------------------------------------------------------------------------
 [[38488,1],1]: A high-performance Open MPI point-to-point messaging module
was unable to find any relevant network interfaces:

Module: OpenFabrics (openib)
  Host: FRRO741

Another transport will be used instead, although this may result in
lower performance.

NOTE: You can disable this warning by setting the MCA parameter
btl_base_warn_component_unused to 0.
--------------------------------------------------------------------------
/*---------------------------------------------------------------------------*\
  =========                 |
  \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox
   \\    /   O peration     | Website:  https://openfoam.org
    \\  /    A nd           | Version:  6
     \\/     M anipulation  |
\*---------------------------------------------------------------------------*/
Build  : 6-47517f2ebb1b
Exec   : splitMeshRegions -parallel -cellZones -overwrite
Date   : Sep 06 2019
Time   : 16:58:03
Host   : "FRRO741"
PID    : 29028
I/O    : uncollated
Case   : /home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd
nProcs : 6
Slaves : 
5
(
"FRRO741.29029"
"FRRO741.29030"
"FRRO741.29031"
"FRRO741.29032"
"FRRO741.29033"
)

Pstream initialized with:
    floatTransfer      : 0
    nProcsSimpleSum    : 0
    commsType          : nonBlocking
    polling iterations : 0
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

Creating single patch per inter-region interface.

Trying to match regions to existing cell zones.


Number of regions:5

Writing region per cell file (for manual decomposition) to "/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/constant/cellToRegion"

Writing region per cell as volScalarField to "/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/0/cellToRegion"

Region    Cells
------    -----
0    607
1    41874
2    21286
3    128
4    352

Region    Zone    Name
------    ----    ----
0    -1    region1 
1    0    AirAmbiant
2    3    Dissipateur
3    2    TriacAlu
4    1    TriacPlastique

Sizes of interfaces between regions:

Interface    Region    Region    Faces
---------    ------    ------    -----
0        3    4    88
1        0    1    443
2        2    3    137
3        1    2    18783
4        1    3    79
5        1    4    240

Reading volScalarField cellToRegion


Adding patches


Adding patches

For interface between region TriacAlu and TriacPlastique added patches
    6    TriacAlu_to_TriacPlastique
    7    TriacPlastique_to_TriacAlu
For interface between region region1 and AirAmbiant added patches
    8    region1_to_AirAmbiant
    9    AirAmbiant_to_region1
For interface between region Dissipateur and TriacAlu added patches
    10    Dissipateur_to_TriacAlu
    11    TriacAlu_to_Dissipateur
For interface between region AirAmbiant and Dissipateur added patches
    12    AirAmbiant_to_Dissipateur
    13    Dissipateur_to_AirAmbiant
For interface between region AirAmbiant and TriacAlu added patches
    14    AirAmbiant_to_TriacAlu
    15    TriacAlu_to_AirAmbiant
For interface between region AirAmbiant and TriacPlastique added patches
    16    AirAmbiant_to_TriacPlastique
    17    TriacPlastique_to_AirAmbiant

Region 0
-------- 
Creating mesh for region 0 region1
Testing:"/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/system/region1/fvSchemes"
Writing dummy "region1/fvSchemes"
Writing dummy "region1/fvSolution"
Mapping fields
Mapping field cellToRegion
Deleting empty patches
Writing new mesh
Writing addressing to base mesh
Writing map pointRegionAddressing from region0 points back to base mesh.
Writing map faceRegionAddressing from region0 faces back to base mesh.
Writing map cellRegionAddressing from region0 cells back to base mesh.
Writing map boundaryRegionAddressing from region0 boundary back to base mesh.

Region 1
-------- 
Creating mesh for region 1 AirAmbiant
Testing:"/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/system/AirAmbiant/fvSchemes"
Mapping fields
Mapping field cellToRegion
Deleting empty patches
Writing new mesh
Writing addressing to base mesh
Writing map pointRegionAddressing from region1 points back to base mesh.
Writing map faceRegionAddressing from region1 faces back to base mesh.
Writing map cellRegionAddressing from region1 cells back to base mesh.
Writing map boundaryRegionAddressing from region1 boundary back to base mesh.

Region 2
-------- 
Creating mesh for region 2 Dissipateur
Testing:"/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/system/Dissipateur/fvSchemes"
Mapping fields
Mapping field cellToRegion
Deleting empty patches
Writing new mesh
Writing addressing to base mesh
Writing map pointRegionAddressing from region2 points back to base mesh.
Writing map faceRegionAddressing from region2 faces back to base mesh.
Writing map cellRegionAddressing from region2 cells back to base mesh.
Writing map boundaryRegionAddressing from region2 boundary back to base mesh.

Region 3
-------- 
Creating mesh for region 3 TriacAlu
Testing:"/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/system/TriacAlu/fvSchemes"
Mapping fields
Mapping field cellToRegion
Deleting empty patches
Writing new mesh
Writing addressing to base mesh
Writing map pointRegionAddressing from region3 points back to base mesh.
Writing map faceRegionAddressing from region3 faces back to base mesh.
Writing map cellRegionAddressing from region3 cells back to base mesh.
Writing map boundaryRegionAddressing from region3 boundary back to base mesh.

Region 4
-------- 
Creating mesh for region 4 TriacPlastique
Testing:"/home/utilisateur/OpenFOAM/OpenFOAM-6/run/PPLDEC0195Bd/processor0/system/TriacPlastique/fvSchemes"
Mapping fields
Mapping field cellToRegion
Deleting empty patches
Writing new mesh
Writing addressing to base mesh
Writing map pointRegionAddressing from region4 points back to base mesh.
Writing map faceRegionAddressing from region4 faces back to base mesh.
Writing map cellRegionAddressing from region4 cells back to base mesh.
Writing map boundaryRegionAddressing from region4 boundary back to base mesh.
End

Finalising parallel run
[FRRO741:29023] 5 more processes have sent help message help-mpi-btl-base.txt / btl:no-nics
[FRRO741:29023] Set MCA parameter "orte_base_help_aggregate" to 0 to see all help / error messages

[GuiMagyar]

Still no solution ...


But If I move the locationInMesh to (5e-3 5e-3 5e-3) Then AirAmbiant and region 1 are now inversed cf attached screenshot... I really do not understand what is happening xD


No clue ? (

[Atefeh T]

hey, did you find out how to get rid of this extra region? I have exactly the same problem

[Yann]

Hello,

I'm not sure it will solve the issue, but you might try using the -cellZonesOnly option rather than -cellZones.

Hope this helps,
Yann