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[snappyHexMesh] Prblem with refinement at angle walls

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Old   April 14, 2020, 01:27
Default Prblem with refinement at angle walls
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felipe ortega
Join Date: Sep 2019
Posts: 15
Rep Power: 6
flowwwww is on a distinguished road
Hello everyone,


I am working in a problem that involves heat transfer. My geometry consists in four ducts that inyect and extract hot air to a chamber. There are two inyectors and two extractors quite simples. However, they have some angle walls that i have not be able to refine well.
here are some pics.
1.png
2.png
3.png
4.png
5.png


My snappyHexMesh file is the next one.


Code:
castellatedMesh true;
snap            true;
addLayers       false;



geometry
{
    walls.stl
    {
        type triSurfaceMesh;
        name walls;
    }
    inlet1.stl
    {
        type triSurfaceMesh;
        name inlet1;
    }
    inlet2.stl
    {
        type triSurfaceMesh;
        name inlet2;
    }
    outlet1.stl
    {
        type triSurfaceMesh;
        name outlet1;
    }
    outlet2.stl
    {
        type triSurfaceMesh;
        name outlet2;
    }


castellatedMeshControls
{
    maxLocalCells 100000;
    maxGlobalCells 2000000;
    minRefinementCells 10;
    maxLoadUnbalance 0.10;
    nCellsBetweenLevels 3;

    features
    (
        {
            file "walls.eMesh";
            level 2;
        }
    );



refinementSurfaces
    {
        walls
        {
            level (2 2);
            patchInfo
            {
                type wall;
                inGroups (walls);
            }
        }
        inlet1
        {
            level (2 2);
            patchInfo
            {
                type patch;
                inGroups (inlet1);
            }
       }
       inlet2
        {
            level (2 2);
            patchInfo
            {
                type patch;
                inGroups (inlet2);
            }
       }
       outlet1
        {
            level (2 2);
            patchInfo
            {
                type patch;
                inGroups (outlet1);
            }
       }
       outlet2
        {
            level (2 2);
            patchInfo
            {
                type patch;
                inGroups (outlet2);
            }
       }

    }
    resolveFeatureAngle 30;

    locationInMesh (4.0 2.0 0.5);

    allowFreeStandingZoneFaces true;
}


snapControls
{
    nSmoothPatch 10;
    tolerance 1.5;
    nSolveIter 100;
    nRelaxIter 10;
        nFeatureSnapIter 35;
        implicitFeatureSnap false;
        explicitFeatureSnap true;
        multiRegionFeatureSnap true;
}
meshQualityControls
{
    maxNonOrtho 90;
    maxBoundarySkewness 20;
    maxInternalSkewness 4;
    maxConcave 80;
    minVol -1e30;
    minTetQuality 1e-30;
    minArea -1;
    minTwist 0.02;
    minDeterminant 0.001;
    minFaceWeight 0.02;
    minVolRatio 0.01;
    minTriangleTwist -1;

    nSmoothScale 4;
    errorReduction 0.75;
}



debug 0;
mergeTolerance 1e-6;
UPDATE:
When i run checkMesh, i obtain the next results.


Code:
Checking geometry...
    Overall domain bounding box (0 -0.0500007 -0.0529237) (21.74 3.27545 0.535)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-1.05951e-17 2.05273e-16 1.47767e-14) OK.
    Max cell openness = 6.12091e-16 OK.
    Max aspect ratio = 46.2304 OK.
    Minimum face area = 2.504e-07. Maximum face area = 0.0134802.  Face area magnitudes OK.
    Min volume = 4.22417e-07. Max volume = 0.00135733.  Total volume = 41.9109.  Cell volumes OK.
    Mesh non-orthogonality Max: 88.8062 average: 12.8578
   *Number of severely non-orthogonal (> 70 degrees) faces: 3731.
    Non-orthogonality check OK.
  <<Writing 3731 non-orthogonal faces to set nonOrthoFaces
    Face pyramids OK.
 ***Max skewness = 6.10403, 24 highly skew faces detected which may impair the quality of the results
  <<Writing 24 skew faces to set skewFaces
    Coupled point location match (average 0) OK.
 ***Error in face tets: 184 faces with low quality or negative volume decomposition tets.
  <<Writing 124 faces with low quality or negative volume decomposition tets to set lowQualityTetFaces
   *Edges too small, min/max edge length = 0 0.132132, number too small: 28
  <<Writing 28 points on short edges to set shortEdges
  <<Writing 66 near (closer than 2.20007e-05 apart) points to set nearPoints
   *There are 2716 faces with concave angles between consecutive edges. Max concave angle = 77.0543 degrees.
  <<Writing 2716 faces with concave angles to set concaveFaces
    Face flatness (1 = flat, 0 = butterfly) : min = 0.121927  average = 0.999431
   *There are 110 faces with ratio between projected and actual area < 0.8
    Minimum ratio (minimum flatness, maximum warpage) = 0.121927
  <<Writing 110 warped faces to set warpedFaces
    Cell determinant (wellposedness) : minimum: 1.67588e-09 average: 11.1604
 ***Cells with small determinant (< 0.001) found, number of cells: 1421
  <<Writing 1421 under-determined cells to set underdeterminedCells
 ***Concave cells (using face planes) found, number of cells: 24745
  <<Writing 24745 concave cells to set concaveCells
    Face interpolation weight : minimum: 0.0200923 average: 0.450171
 ***Faces with small interpolation weight (< 0.05) found, number of faces: 151
  <<Writing 151 faces with low interpolation weights to set lowWeightFaces
    Face volume ratio : minimum: 0.0413339 average: 0.801845
    Face volume ratio check OK.

Failed 5 mesh checks.

End

If someone could help me i will really appreciate it.


Best regards.

Last edited by flowwwww; April 14, 2020 at 10:46.
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