[leobiscaino]

Hello CFD users, I’m new to CFD and I’m trying to create a mesh for the case described below. As you can see, the trailing edge is not working as expected.

Block mesh dict:

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2312 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

scale 1;

vertices
(
(0 0 0)
(12.04 0 0)
(12.04 -12.04 0)
(0 -12.04 0)
(0 0 -12.04)
(12.04 0 -12.04)
(12.04 -12.04 -12.04)
(0 -12.04 -12.04)
);

blocks
(
hex (0 1 2 3 4 5 6 7) (100 100 100) simpleGrading (1 1 1)
);

edges
(
);

boundary
(
topAndBottom
{
type patch;
faces
(
(3 7 6 2)
(1 5 4 0)
);
}

inlet
{
type patch;
faces
(
(0 4 7 3)
);
}

outlet
{
type patch;
faces
(
(2 6 5 1)
);
}

symFront
{
type patch;
faces
(
(4 5 6 7)
);
}

symBack
{
type symmetryPlane;
faces
(
(0 3 2 1)
);
}
);


SnappyHexMeshDict

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

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2312 |
| \\ / 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 false;
addLayers false;

// Geometry. Definition of all surfaces.
geometry
{
blade_0.stl
{
type triSurfaceMesh;
name blade;
}

refinementBox
{
type searchableBox;
min (4 -4 -8);
max (8 0 -4);
}
}

// Settings for the castellatedMesh generation.
castellatedMeshControls
{
// Refinement parameters
maxLocalCells 100000;
maxGlobalCells 2000000;
minRefinementCells 100;
nCellsBetweenLevels 3;

// Explicit feature edge refinement
features
(
{
file "blade_0.eMesh";
level 3;
}
);

// Surface based refinement
refinementSurfaces
{
blade
{
level (9 9); // Refinamento padrão para toda a superfície
regions
{
tips { level (13 13); }
patch_cut { level (13 13); }
patch_upper { level (13 13); }
patch_le { level (11 11); } // Refinamento mais fino para borda de ataque
patch_lower { level (13 13); }
}
}
}

resolveFeatureAngle 30;

// Region-wise refinement
refinementRegions
{
refinementBox
{
mode inside;
levels
(
(1 8)
);
}
}

// Mesh selection
locationInMesh (6.02 -2 -6.02);
allowFreeStandingZoneFaces true;
}

// Settings for the snapping.
snapControls
{
nSmoothPatch 3;
tolerance 1.0;
nSolveIter 60;
nRelaxIter 5;

}

// Settings for the layer addition.
addLayersControls
{
relativeSizes true;

layers
{
blade
{
nSurfaceLayers 5;
}
}

expansionRatio 1.0;
finalLayerThickness 0.3;
minThickness 0.1;
nGrow 0;

featureAngle 60;
slipFeatureAngle 30;
nRelaxIter 3;
nSmoothSurfaceNormals 1;
nSmoothNormals 3;
nSmoothThickness 10;
maxFaceThicknessRatio 0.5;
maxThicknessToMedialRatio 0.3;
minMedialAxisAngle 90;
nBufferCellsNoExtrude 0;
nLayerIter 50;
}

// Mesh quality controls
meshQualityControls
{
maxNonOrtho 65;
maxBoundarySkewness 20;
maxInternalSkewness 4;
maxConcave 80;
minVol 1e-13;
minTetQuality 1e-30;
minArea -1;
minTwist 0.05;
minDeterminant 0.001;
minFaceWeight 0.05;
minVolRatio 0.01;
minTriangleTwist -1;
nSmoothScale 4;
errorReduction 0.75;
}

// Advanced settings
mergeTolerance 1e-6;

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


SurfaceFeatureExtract



/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: v2206 |
| \\ / A nd | Website: www.openfoam.com |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object surfaceFeatureExtractDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

blade_0.stl
{
// How to obtain raw features (extractFromFile || extractFromSurface)
extractionMethod extractFromSurface;

// Mark edges whose adjacent surface normals are at an angle less
// than includedAngle as features
// - 0 : selects no edges
// - 180: selects all edges
includedAngle 150;

// Write options

// Write features to obj format for postprocessing
writeObj false;
}


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

[AtoHM]

You might be hitting the maximum local or global cells value. In that case snappy immediately stops refinement. Also falling under minRefinementCells can cause this. I usually use 1 here, so it refines until everything I want refined is refined.

Originally Posted by leobiscaino

castellatedMeshControls
{
// Refinement parameters
maxLocalCells 100000;
maxGlobalCells 2000000;
minRefinementCells 100;

[leobiscaino]

Unfortunatelly, It didn't work :/ I put minRefinementCells = 1 and maximum local and global cells value = 200000, 2000000.