rahulcfd10 |
March 2, 2022 17:45 |
Error in the refinement region generation
1 Attachment(s)
Hello!
I have tried to use snappyHexMesh to generate 2 refinement zones (cuboids) around my object with different refinement levels. After generating the castellated mesh, my refinement regions do not match with the refinement region I have specified on my code.
Kindly find the images of the error and my code attached.
Let me know your thoughts
Thank you
Rahul
Code:
/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 8
\\/ 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. Definition of all surfaces. All surfaces are of class
// searchableSurface.
// Surfaces are used
// - to specify refinement for any mesh cell intersecting it
// - to specify refinement for any mesh cell inside/outside/near
// - to 'snap' the mesh boundary to the surface
geometry
{
sphere35cmswv2.stl
{
type triSurfaceMesh;
name stl1; //patch name
}
refinementBox1
{
type searchableBox;
min (-0.4875 -0.4375 -0.4375); //(-0.4875 -0.6125 -0.6125); //(-1.0 -0.7 0.0);
max (3.4625 0.7875 0.7875); //(1.4875 0.7875 0.7875); //(1.4875 0.6125 0.6125); //( 8.0 0.7 2.5);
}
refinementBox2
{
type searchableBox;
min (-0.875 -1.05 -1.05); //(-0.875 -1.225 -1.225); //(-1.0 -0.7 0.0);
max (6.825 1.4 1.4); //(2.975 1.4 1.4); //(2.975 1.225 1.225); //( 8.0 0.7 2.5);
}
};
// Settings for the castellatedMesh generation.
castellatedMeshControls
{
// Refinement parameters
// ~~~~~~~~~~~~~~~~~~~~~
// If local number of cells is >= maxLocalCells on any processor
// switches from from refinement followed by balancing
// (current method) to (weighted) balancing before refinement.
maxLocalCells 100000;
// Overall cell limit (approximately). Refinement will stop immediately
// upon reaching this number so a refinement level might not complete.
// Note that this is the number of cells before removing the part which
// is not 'visible' from the keepPoint. The final number of cells might
// actually be a lot less.
maxGlobalCells 2000000;
// The surface refinement loop might spend lots of iterations refining just a
// few cells. This setting will cause refinement to stop if <= minimumRefine
// are selected for refinement. Note: it will at least do one iteration
// (unless the number of cells to refine is 0)
minRefinementCells 10;
// Allow a certain level of imbalance during refining
// (since balancing is quite expensive)
// Expressed as fraction of perfect balance (= overall number of cells /
// nProcs). 0=balance always.
maxLoadUnbalance 0.10;
// Number of buffer layers between different levels.
// 1 means normal 2:1 refinement restriction, larger means slower
// refinement.
nCellsBetweenLevels 3; //3; //10;
// Explicit feature edge refinement
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// Specifies a level for any cell intersected by its edges.
// This is a featureEdgeMesh, read from constant/triSurface for now.
features
(
{
file "sphere35cmswv2.eMesh";
level 3;
}
);
// Surface based refinement
// ~~~~~~~~~~~~~~~~~~~~~~~~
// Specifies two levels for every surface. The first is the minimum level,
// every cell intersecting a surface gets refined up to the minimum level.
// The second level is the maximum level. Cells that 'see' multiple
// intersections where the intersections make an
// angle > resolveFeatureAngle get refined up to the maximum level.
refinementSurfaces
{
stl1
{
// Surface-wise min and max refinement level
level (2 2); //(2 3); //(5 6);
// Optional specification of patch type (default is wall). No
// constraint types (cyclic, symmetry) etc. are allowed.
patchInfo
{
type wall;
inGroups (stl1);
}
}
}
// Resolve sharp angles
resolveFeatureAngle 30;
planarAngle 30;
// Region-wise refinement
// ~~~~~~~~~~~~~~~~~~~~~~
// Specifies refinement level for cells in relation to a surface. One of
// three modes
// - distance. 'levels' specifies per distance to the surface the
// wanted refinement level. The distances need to be specified in
// descending order.
// - inside. 'levels' is only one entry and only the level is used. All
// cells inside the surface get refined up to the level. The surface
// needs to be closed for this to be possible.
// - outside. Same but cells outside.
refinementRegions
{
refinementBox1
{
mode inside;
levels ((3 3));//((3 3)); //((3 2)); //((1E15 4));
}
refinementBox2
{
mode inside;
levels ((2 2)); //((3 2)); //((1E15 4));
}
}
// Mesh selection
// ~~~~~~~~~~~~~~
// After refinement patches get added for all refinementSurfaces and
// all cells intersecting the surfaces get put into these patches. The
// section reachable from the locationInMesh is kept.
// NOTE: This point should never be on a face, always inside a cell, even
// after refinement.
locationInMesh (1 2 2); //(3.0001 3.0001 0.43);
// Whether any faceZones (as specified in the refinementSurfaces)
// are only on the boundary of corresponding cellZones or also allow
// free-standing zone faces. Not used if there are no faceZones.
allowFreeStandingZoneFaces true;
}
// Settings for the snapping.
snapControls
{
//- Number of patch smoothing iterations before finding correspondence
// to surface
nSmoothPatch 3;
//- Relative distance for points to be attracted by surface feature point
// or edge. True distance is this factor times local
// maximum edge length.
tolerance 2.0;
//- Number of mesh displacement relaxation iterations.
nSolveIter 30;
//- Maximum number of snapping relaxation iterations. Should stop
// before upon reaching a correct mesh.
nRelaxIter 5;
// Feature snapping
//- Number of feature edge snapping iterations.
// Leave out altogether to disable.
nFeatureSnapIter 10;
//- Detect (geometric only) features by sampling the surface
// (default=false).
implicitFeatureSnap true; //false;
//- Use castellatedMeshControls::features (default = true)
explicitFeatureSnap true;
//- Detect points on multiple surfaces (only for explicitFeatureSnap)
multiRegionFeatureSnap false;
}
// Settings for the layer addition.
addLayersControls
{
// Are the thickness parameters below relative to the undistorted
// size of the refined cell outside layer (true) or absolute sizes (false).
relativeSizes true;
// Per final patch (so not geometry!) the layer information
layers
{
"(stl1|sphere35cmswv2).*"
{
nSurfaceLayers 10; //1;
}
}
expansionRatio 1.0;
finalLayerThickness 0.1;
finalLayerRatio 0.01;
minThickness 0.002;
nGrow 0;
featureAngle 30;
nRelaxIter 10;
nSmoothSurfaceNormals 1;
nSmoothNormals 3;
nSmoothThickness 10;
maxFaceThicknessRatio 0.5;
maxThicknessToMedialRatio 0.3;
minMedianAxisAngle 40;
nBufferCellsNoExtrude 0;
nLayerIter 100;
nRelaxedIter 20;
}
// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls
{
#include "meshQualityDict"
}
// 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;
// ************************************************************************* //
Code:
/*--------------------------------*- C++ -*----------------------------------*\
========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Version: 8
\\/ M anipulation |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
convertToMeters 1;
/*vertices
(
(-5 -4 0)
(15 -4 0)
(15 4 0)
(-5 4 0)
(-5 -4 8)
(15 -4 8)
(15 4 8)
(-5 4 8)
);
*/
xmin -2.1; //-2.275;
xmax 17.5; //8.75; //8.575;
ymin -3.15; //-3.325;
ymax 3.5; //3.325;
zmin -3.15; //-3.325;
zmax 3.5; //3.325;
deltax 0.1;
deltay 0.1;
deltaz 0.1;
lnx #calc "abs(($xmax) - ($xmin))";
lny #calc "abs(($ymax) - ($ymin))";
lnz #calc "abs(($zmax) - ($zmin))";
xcells #calc "round(abs(($lnx)/$deltax))";
ycells #calc "round(abs(($lny)/$deltay))";
zcells #calc "round(abs(($lnz)/$deltaz))";
vertices
(
//BLOCK1
($xmin $ymin $zmin) //0
($xmax $ymin $zmin) //1
($xmax $ymax $zmin) //2
($xmin $ymax $zmin) //3
($xmin $ymin $zmax) //4
($xmax $ymin $zmax) //5
($xmax $ymax $zmax) //6
($xmin $ymax $zmax) //7
);
blocks
(
hex (0 1 2 3 4 5 6 7) ($xcells $ycells $zcells) simpleGrading (1 1 1)
);
edges
(
);
boundary
(
frontAndBack
{
type wall;
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)
);
}
leftWall //lowerWall
{
type wall;
faces
(
(0 3 2 1)
);
}
rightWall //upperWall
{
type wall;
faces
(
(4 5 6 7)
);
}
);
// ************************************************************************* //
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