[robboflea]

Hi all,


I have a problem with shm that I cannot seem to solve. Below you can see my domain.
domain.png


I managed to mesh successfully the domain with the following snappyHexMeshDict

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v1812                                 |
|   \\  /    A nd           | Web:      www.OpenFOAM.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    location    "system";
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

castellatedMesh       true; //or false to de-activate
snap                  true;
addLayers             false;
mergeTolerance        1e-6;

geometry
{
    Scaled_domain.stl // STL filename
    {
        type triSurfaceMesh;
        name domain;

        regions
        {
            walls
            {
                name walls;
            }
            inlet
            {
                name inlet;
            }
            outlet
            {
                name outlet;
            }
        }
    }
}

castellatedMeshControls
{
    maxLocalCells 500000;
    maxGlobalCells 2000000;
    nCellsBetweenLevels 4;
    resolveFeatureAngle 70;
    minRefinementCells 0;
    allowFreeStandingZoneFaces false;
    
    locationInMesh (2E-4 2E-4 2.2E-4);
    
    features
    (
        {
            file "Scaled_domain.eMesh"; // file containing edge mesh
            levels ((0.0 1)(0.1 1));               // level of refinement
        }
    );


    refinementSurfaces
    {
        domain
        {
            level (2 2);
            regions
            {
                walls
                {
                    level (1 1);
                    patchInfo
                    {
                        type    wall;
                    }
                }

                inlet
                {
                    level (2 2);
                    patchInfo
                    {
                        type    patch;
                    }
                }

                outlet
                {
                    level (2 2);
                    patchInfo
                    {
                        type    patch;
                    }
                }
            }
        }
    }
    
    refinementRegions
    {
    }
}

snapControls
{
    nSmoothPatch 5;
    tolerance 1.0;
    nSolveIter 100;
    nRelaxIter 5;
    nFeatureSnapIter 10;
    implicitFeatureSnap false;
    explicitFeatureSnap true;
    multiRegionFeatureSnap false;
}

addLayersControls
{
    layers
    {
        walls
        {
            nSurfaceLayers 10;
        }
        inlet
        {
            nSurfaceLayers 10;
        }
        outlet
        {
            nSurfaceLayers 10;
        }
    }
    
    relativeSizes true;
    expansionRatio 1.1;
    finalLayerThickness 0.9;
    minThickness 0.1;
    nGrow 5;
    featureAngle 90;
    maxFaceThicknessRatio 0.5;
    nSmoothSurfaceNormals 1;
    nSmoothThickness 10;
    minMedialAxisAngle 90;
    maxThicknessToMedialRatio 0.3;
    maxThicknessToMedialRatio 0.3;
    nSmoothNormals 3;
    nRelaxIter 5;
    nBufferCellsNoExtrude 0;
    nLayerIter 50;
    nRelaxedIter 20;
}

meshQualityControls
{ 
    maxNonOrtho 65;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave 80;
    minVol 1.00E-13;
    minTetQuality  -1e15;
    minArea -1;
    minTwist 0.05;
    minDeterminant 0.001;
    minFaceWeight 0.05;
    minVolRatio 0.01;
    minTriangleTwist -1; // >0 for fluent compatibility
    minFlatness 0.5;
    nSmoothScale 4;
    errorReduction 0.75;
}

debugFlags
(
);

Below you can see a slice of the mesh obtained using the above dictionary.
shm_ok.png


However, if trying to refine the mesh by changing the line:

levels ((0.0 1)(0.1 1));               // level of refinement

in the features refinement section to:

levels ((0.0 2)(0.1 1));               // level of refinement

the final mesh becomes completely wrong as you can see from the image below:
shm_error.png


It looks that in this case shm removes the wrong section of mesh but I cannot understand why is it doing so. There is literally no other modification in the shm dictionary. The error is repeatable and happens consistently. In both cases I delete all previous mesh files and even restart with a new initial block mesh.


Any help would be much appreciated. Thanks a lot.