| clktp |
August 26, 2016 09:37 |
snappyHexMesh can't create refimenet region
3 Attachment(s)
Hello,
I have been creating mesh for a 3d wind turbine analysis with openFoam 2.4.0, but I haven't succeed yet. It is a steady-state analysis so I use periodic boundary conditions and my domain is like a 120 degree pie, Attachment 50112.
It is blockMeshDict file that creates this geometry.
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.4.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
object blockMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
convertToMeters 1;
vertices
(
(-100 0 0)
(100 0 0)
(-100 -173.20 100)
(100 -173.20 100)
(100 173.20 100)
(-100 173.20 100)
);
blocks
(
hex (0 1 1 0 2 3 4 5)(100 100 100) simpleGrading (1 1 100)
);
edges
(
arc 2 5 (-100 0 200)
arc 3 4 (100 0 200)
);
/*defaultPatch
{
name frontAndBack;
type wall;
}*/
boundary
(
/* inlet
{
type patch;
faces
(
(0 0 5 2 )
);
}*/
side1
{
type cyclic;
faces
(
(0 2 3 1)
);
neighbourPatch side2;
}
side2
{
type cyclic;
faces
(
(0 1 4 5)
);
neighbourPatch side1;
}
inlet
{
type patch;
faces
(
(0 0 5 2 )
);
}
outlet
{
type patch;
faces
(
(1 3 4 1)
);
}
top
{
type patch;
faces
(
(5 2 3 4)
);
}
collapsed
{
type empty;
faces
(
(0 1 1 0)
);
}
);
mergePatchPairs
(
);
// ************************************************************************* //
I've managed to create the blockmesh without any error. Afterwards I wanted to snappyHexMesh to generate my final mesh contains wind turbine and refinement region, also I would use it as MRF source. However I couldn't do it. snappyHexMesh gives me this error.
Code:
Surface refinement iteration 6
------------------------------
Marked for refinement due to surface intersection : 1 cells.
Marked for refinement due to curvature/regions : 22 cells.
Determined cells to refine in = 0.29 s
Selected for refinement : 30 cells (out of 1081578)
Stopping refining since too few cells selected.
Removing mesh beyond surface intersections
------------------------------------------
Found point (8.123 3.9823 10.13123123) in global region 0 out of 2 regions.
Keeping all cells in region 0 containing point (8.123 3.9823 10.13123123)
Selected for keeping : 1075852 cells.
Edge intersection testing:
Number of edges : 3275257
Number of edges to retest : 12183
Number of intersected edges : 18589
Shell refinement iteration 0
----------------------------
Marked for refinement due to distance to explicit features : 0 cells.
Marked for refinement due to refinement shells : 225852 cells.
Determined cells to refine in = 4.46 s
Selected for internal refinement : 225852 cells (out of 1075852)
hexRef8 : Dumping cell as obj to "/home/taygun/Desktop/OpenFOAM/OpenFOAM-2.4.0/run/turbineDesign/turbineGridTest/test_10/cell_40.obj"
--> FOAM FATAL ERROR:
cell 40 of level 0 does not seem to have 8 points of equal or lower level
cellPoints:6(141 142 40 41 242 243)
pointLevels:6{0}
From function hexRef8::setRefinement(const labelList&, polyTopoChange&)
in file polyTopoChange/polyTopoChange/hexRef8.C at line 3775.
FOAM aborting
#0 Foam::error::printStack(Foam::Ostream&) at ??:?
#1 Foam::error::abort() at ??:?
#2 Foam::hexRef8::setRefinement(Foam::List<int> const&, Foam::polyTopoChange&) at ??:?
#3 Foam::meshRefinement::refine(Foam::List<int> const&) at ??:?
#4 Foam::meshRefinement::refineAndBalance(Foam::string const&, Foam::decompositionMethod&, Foam::fvMeshDistribute&, Foam::List<int> const&, double) at ??:?
#5 Foam::autoRefineDriver::shellRefine(Foam::refinementParameters const&, int) at ??:?
#6 Foam::autoRefineDriver::doRefine(Foam::dictionary const&, Foam::refinementParameters const&, Foam::snapParameters const&, bool, Foam::dictionary const&) at ??:?
#7 ? at ??:?
#8 __libc_start_main in "/lib/x86_64-linux-gnu/libc.so.6"
#9 ? at ??:?
Aborted (core dumped)
The cell that gives the error is here Attachment 50114
This is my snappyHexMeshDict file
Code:
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.1 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ 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
{
poyra36_2.stl
{
type triSurfaceMesh;
name blade;
}
rCylinder
{
type searchableCylinder;
point1 (-20 0 0); // Height
point2 (20 0 0); // Vector
radius 60;
}
/* rBox
{
type searchableCylinder;
min (-800 -700 0)kkjjjk;
max (1700 700 80 );
} */
}
// 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 5000000;
// 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 25000000;
// 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 100;
// 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 4;
// 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 "poyra36_2.eMesh";
level 5;
}
);
// 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
{
/* rCylinder
{
mode inside;
level (2 2);
faceZone rCylinder;
cellZone rCylinder;
cellZoneInside inside;
}*/
/* rCylinder
{
mode inside;
level (1 1);
cellZone rCylinder;
}*/
blade
{
// Surface-wise min and max refinement level
level (3 4);
// Optional region-wise level specification
regions
{
/* rCylinder
{
mode inside;
level (1 1);
cellZone rCylinder;
}*/
}
//- Optional angle to detect small-large cell situation
// perpendicular to the surface. Is the angle of face w.r.t.
// the local surface normal. Use on flat(ish) surfaces only.
// Otherwise leave out or set to negative number.
//perpendicularAngle 10;
//- Optional faceZone and (for closed surface) cellZone with
// how to select the cells that are in the cellZone
// (inside / outside / specified insidePoint)
//faceZone sphere;
//cellZone sphere;
//cellZoneInside inside; //outside/insidePoint
}
}
resolveFeatureAngle 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
{
rCylinder
{
mode inside;
levels ((10 15));
faceZone rCylinder;
cellZone rCylinder;
cellZoneInside inside;
}
/*
windTurbine1
{
mode inside;
levels ((6 6));
}
windTurbine2
{
mode inside;
levels ((6 6));
}
*/ //sphere.stl
//{
// mode distance;
// levels ((1.0 5) (2.0 3));
//}
}
// 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 (8.123 3.9823 10.13123123123);
// 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 4.0;
//- Number of mesh displacement relaxation iterations.
nSolveIter 20;
//- Maximum number of snapping relaxation iterations. Should stop
// before upon reaching a correct mesh.
nRelaxIter 5;
}
// 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
{
"blade"
{
nSurfaceLayers 3;
}
}
// Expansion factor for layer mesh
expansionRatio 1.1;
// Wanted thickness of final added cell layer. If multiple layers
// is the thickness of the layer furthest away from the wall.
// See relativeSizes parameter.
finalLayerThickness 0.3;
// Minimum thickness of cell layer. If for any reason layer
// cannot be above minThickness do not add layer.
// See relativeSizes parameter.
minThickness 0.1;
// If points get not extruded do nGrow layers of connected faces that are
// also not grown. This helps convergence of the layer addition process
// close to features.
// Note: changed(corrected) w.r.t 17x! (didn't do anything in 17x)
nGrow 0;
// Advanced settings
// When not to extrude surface. 0 is flat surface, 90 is when two faces
// are perpendicular
featureAngle 60;
// Maximum number of snapping relaxation iterations. Should stop
// before upon reaching a correct mesh.
nRelaxIter 5;
// Number of smoothing iterations of surface normals
nSmoothSurfaceNormals 1;
// Number of smoothing iterations of interior mesh movement direction
nSmoothNormals 3;
// Smooth layer thickness over surface patches
nSmoothThickness 10;
// Stop layer growth on highly warped cells
maxFaceThicknessRatio 0.5;
// Reduce layer growth where ratio thickness to medial
// distance is large
maxThicknessToMedialRatio 0.3;
// Angle used to pick up medial axis points
// Note: changed(corrected) w.r.t 16x! 90 degrees corresponds to 130 in 16x.
minMedianAxisAngle 90;
// Create buffer region for new layer terminations
nBufferCellsNoExtrude 0;
// Overall max number of layer addition iterations. The mesher will exit
// if it reaches this number of iterations; possibly with an illegal
// mesh.
nLayerIter 50;
// Max number of iterations after which relaxed meshQuality controls
// get used. Up to nRelaxIter it uses the settings in meshQualityControls,
// after nRelaxIter it uses the values in meshQualityControls::relaxed.
nRelaxedIter 20;
}
// Generic mesh quality settings. At any undoable phase these determine
// where to undo.
meshQualityControls
{
//- Maximum non-orthogonality allowed. Set to 180 to disable.
maxNonOrtho 65;
//- Max skewness allowed. Set to <0 to disable.
maxBoundarySkewness 20;
maxInternalSkewness 3.5;
//- Max concaveness allowed. Is angle (in degrees) below which concavity
// is allowed. 0 is straight face, <0 would be convex face.
// Set to 180 to disable.
maxConcave 80;
//- Minimum pyramid volume. Is absolute volume of cell pyramid.
// Set to a sensible fraction of the smallest cell volume expected.
// Set to very negative number (e.g. -1E30) to disable.
minVol 1e-13;
//- Minimum quality of the tet formed by the face-centre
// and variable base point minimum decomposition triangles and
// the cell centre. Set to very negative number (e.g. -1E30) to
// disable.
// <0 = inside out tet,
// 0 = flat tet
// 1 = regular tet
minTetQuality 1e-30;
//- Minimum face area. Set to <0 to disable.
minArea -1;
//- Minimum face twist. Set to <-1 to disable. dot product of face normal
//- and face centre triangles normal
minTwist 0.05;
//- minimum normalised cell determinant
//- 1 = hex, <= 0 = folded or flattened illegal cell
minDeterminant 0.001;
//- minFaceWeight (0 -> 0.5)
minFaceWeight 0.05;
//- minVolRatio (0 -> 1)
minVolRatio 0.01;
//must be >0 for Fluent compatibility
minTriangleTwist -1;
//- if >0 : preserve single cells with all points on the surface if the
// resulting volume after snapping (by approximation) is larger than
// minVolCollapseRatio times old volume (i.e. not collapsed to flat cell).
// If <0 : delete always.
//minVolCollapseRatio 0.5;
// Advanced
//- Number of error distribution iterations
nSmoothScale 4;
//- amount to scale back displacement at error points
errorReduction 0.75;
// Optional : some meshing phases allow usage of relaxed rules.
// See e.g. addLayersControls::nRelaxedIter.
relaxed
{
//- Maximum non-orthogonality allowed. Set to 180 to disable.
maxNonOrtho 75;
}
}
// Advanced
// Merge tolerance. Is fraction of overall bounding box of initial mesh.
// Note: the write tolerance needs to be higher than this.
mergeTolerance 1e-6;
// ************************************************************************* //
I have tried different refinement levels but none of them has worked. At first I had refinement zone as MRFSource as well, but somehow it started to didn't work. I don't remember very well what I changed at that point, but I was trying to create patches and that's why I changed blockMeshDict. That wasn't a big change but I remember very well I changed the orientation of the vertices. Apart from that I don't remember very well, because I wasing paying attention and it was going fine. The best for the wind turbine is quit bad right now, but I didn't do anything for it, I mean you can ignore the snapping quality.
The problem is if I remove the refinement zone or move it to the middle of the domain, it works, at least for some refinement levels, but I need in in the middle. I am completely stacked, I have googled it but I couldn't find much. Any help would be appreciated.
Cheers, |
