[DGT]

Good evening,


I am new with snappyHexMesh and currently trying to mesh a square beam.
I am facing problem as can be seen on the picture : there are some steps in the mesh
(the red square is the stl geometry).

Previously, I already tried to mesh the same square but with no angle of attack and it was fine.


I tried to increase the resolution which led me to huge mesh, played with the angle, but nothing seems to work.

If someone knows how to solve my problem, it would be great.


Thank you for your help,


Damien

/*--------------------------------*- C++ -*----------------------------------*\
| =========                 |                                                 |
| \\      /  F ield         | OpenFOAM: The Open Source CFD Toolbox           |
|  \\    /   O peration     | Version:  v2012                                 |
|   \\  /    A nd           | Website:  www.openfoam.com                      |
|    \\/     M anipulation  |                                                 |
\*---------------------------------------------------------------------------*/
FoamFile
{
    version     2.0;
    format      ascii;
    class       dictionary;
    object      snappyHexMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

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


geometry
{
    Beam_5deg_mesh.stl     {type triSurfaceMesh; name Beam1;
                   regions  {solid  {name Beam1;}}
                  }
}


castellatedMeshControls
{
 
    maxLocalCells 1000000;
    maxGlobalCells 20000000;
    minRefinementCells 20;
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 1;
    features (
               {file "Beam_5deg_mesh.eMesh"; level 9;}
    );
    resolveFeatureAngle 4;
    featureAngle 4;
    locationInMesh (1.0001 1.0001 6.43);
    allowFreeStandingZoneFaces true;

    refinementSurfaces
    {
        Beam1
        {
            // Surface-wise min and max refinement level
            level (6 10);

            // Optional specification of patch type (default is wall). No
            // constraint types (cyclic, symmetry) etc. are allowed.
            patchInfo
            {
                type wall;
            }
        }
    }
    refinementRegions
    {
            }
}


snapControls
{   
    nSmoothPatch 10;
    tolerance 0.10;
    nSolveIter 300;
    nRelaxIter 5;
    nFeatureSnapIter 30;
    implicitFeatureSnap false;
    explicitFeatureSnap true;
    multiRegionFeatureSnap false;
}
addLayersControls
{
    relativeSizes false;
    expansionRatio 1.2;
    firstLayerThickness 0.001;
    minThickness 0.0005;
    nGrow 0;
    featureAngle 30;
    slipFeatureAngle 30;
    nRelaxIter 5;
    nSmoothSurfaceNormals 1;
    nSmoothNormals 3;
    nSmoothThickness 10;
    maxFaceThicknessRatio 0.5;
    maxThicknessToMedialRatio 0.3;
    minMedialAxisAngle 90;
    nBufferCellsNoExtrude 0;
    nLayerIter 15;
    layers
    {
        "Beam1"
        {
            nSurfaceLayers 3;
        }
    }
}  

meshQualityControls
{
    #include "meshQualityDict"


    // Advanced

    //- Number of error distribution iterations
    nSmoothScale 4;
    //- Amount to scale back displacement at error points
    errorReduction 0.75;
}

// Advanced

// Write flags
writeFlags
(
    scalarLevels
    layerSets
    layerFields     // write volScalarField for layer coverage
);


// Merge tolerance. Is fraction of overall bounding box of initial mesh.
// Note: the write tolerance needs to be higher than this.
mergeTolerance 1e-6;


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

beam.jpg