diff --git a/tutorials/mesh/cvMesh/simpleShapes/system/cvMeshDict b/tutorials/mesh/cvMesh/simpleShapes/system/cvMeshDict
index f774b1a7530ace167c8911ae0cedcecc1a34e847..7e75ea51d342a519deba705e8c1f535f0a74445a 100644
--- a/tutorials/mesh/cvMesh/simpleShapes/system/cvMeshDict
+++ b/tutorials/mesh/cvMesh/simpleShapes/system/cvMeshDict
@@ -10,12 +10,6 @@ FoamFile
{
version 2.0;
format ascii;
-
- root "";
- case "";
- instance "";
- local "";
-
class dictionary;
object cvMeshDict;
}
@@ -23,6 +17,31 @@ FoamFile
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+/*
+
+Control dictionary for cvMesh - polyhedral mesh generator.
+
+cvMesh phases:
+1. fill volume with initial points (initialPoints subdictionary). An option
+ is to reread from previous set of points.
+
+2. internal point motion (motionControl subdictionary)
+
+3. every once in a while add point duplets/triplets to conform to
+ surfaces and features (surfaceConformation subdictionary)
+
+4. back to 2
+
+5. construct polyMesh.
+ - filter (polyMeshFiltering subdictionary)
+ - check (meshQualityControls subdictionary) and undo filtering
+
+
+See also cvControls.H in the conformalVoronoiMesh library
+
+*/
+
+
// Important:
// ----------
// Any scalar with a name <name>Coeff specifies a value that will be implemented
@@ -39,75 +58,105 @@ FoamFile
geometry
{
// Internal shape
- coneAndSphere.obj
+ coneAndSphere_clean_orient.obj
{
name coneAndSphere;
type triSurfaceMesh;
- tolerance 0.00001;
}
-// // Internal shape
-// coneAndSphere
-// {
-// type searchableSurfaceWithGaps;
-// surface coneAndSphere.obj;
-// gap 0.001;
-// }
-
- // Bounds of domain
- domain.stl
+ // Outside of domain
+ domain_clean_orient.stl
{
+ name domain;
type triSurfaceMesh;
}
}
+// Controls for conforming to the surfaces.
surfaceConformation
{
- // Point that is inside wanted part of geometry.
+ // A point inside surfaces that is inside mesh.
locationInMesh (0 -0.5 0);
- // Balance this between
+ // How far apart are point-duplets generated. Balance this between
// - very low distance: little chance of interference from other
// surfaces
// - largish distance: less non-orthogonality in final cell
// (circumcentre far away from centroid)
pointPairDistanceCoeff 0.1;
+ // Mixed feature edges - both inside and outside edges. Recreated
+ // by inserting triplets of points to recreate a single edge. Done for
+ // all edges emanating from point. triplets of points get inserted
+ // mixedFeaturePointPPDistanceCoeff distance away from feature point.
mixedFeaturePointPPDistanceCoeff 5.0;
+ // Distance to a feature point within which surface and edge
+ // conformation points are excluded - fraction of the local target
+ // cell size
featurePointExclusionDistanceCoeff 0.4;
+ // Distance to an existing feature edge conformation location
+ // within which other edge conformation location are excluded -
+ // fraction of the local target cell size
featureEdgeExclusionDistanceCoeff 0.2;
+ // Optimisation: do not check for surface intersection (of dual edges)
+ // for points near to surface.
surfaceSearchDistanceCoeff 2.5;
+ // Maximum allowable protrusion through the surface before
+ // conformation points are added - fraction of the local target
+ // cell size. These small protusions are (hopefully) done by mesh filtering
+ // instead.
maxSurfaceProtrusionCoeff 0.1;
+ // If feature edge with large angle (so more than 125 degrees) introduce
+ // additional points to create two half angled cells (= mitering).
maxQuadAngle 125;
+ // Frequency to redo surface conformation (expensive).
surfaceConformationRebuildFrequency 10;
+ // Initial and intermediate controls
coarseConformationControls
{
+ // Initial conformation
initial
{
+ // We've got a point poking through the surface. Don't do any
+ // surface conformation if near feature edge (since feature edge
+ // conformation should have priority)
+
+ // distance to search for near feature edges
edgeSearchDistCoeff 1.1;
+
+ // Proximity to a feature edge where a surface hit is
+ // not created, only the edge conformation is created
+ // - fraction of the local target cell size. Coarse
+ // conformation, initial protrusion tests.
surfacePtReplaceDistCoeff 0.5;
}
+ // Same for iterations
iteration
{
edgeSearchDistCoeff 1.25;
surfacePtReplaceDistCoeff 0.7;
}
+ // Stop either at maxIterations or if the number of surface pokes
+ // is very small (iterationToInitialHitRatioLimit * initial number)
+ // Note: perhaps iterationToInitialHitRatioLimit should be absolute
+ // count?
maxIterations 15;
iterationToInitialHitRatioLimit 0.001;
}
+ // Final (at endTime) controls
fineConformationControls
{
initial
@@ -127,45 +176,49 @@ surfaceConformation
iterationToInitialHitRatioLimit 0.001;
}
+ // Geometry to mesh to
geometryToConformTo
{
coneAndSphere
{
featureMethod extendedFeatureEdgeMesh;
- extendedFeatureEdgeMesh "coneAndSphere.extendedFeatureEdgeMesh";
+ extendedFeatureEdgeMesh "coneAndSphere_clean_orient.extendedFeatureEdgeMesh";
}
- domain.stl
+ domain
{
featureMethod extendedFeatureEdgeMesh;
- extendedFeatureEdgeMesh "domain.extendedFeatureEdgeMesh";
+ extendedFeatureEdgeMesh "domain_clean_orient.extendedFeatureEdgeMesh";
}
-
}
additionalFeatures {}
}
+// Controls for seeding initial points and general control of the target
+// cell size (used everywhere)
initialPoints
{
// Do not place point closer than minimumSurfaceDistanceCoeff
// to the surface. Is fraction of local target cell size (see below)
minimumSurfaceDistanceCoeff 0.55;
- initialPointsMethod autoDensity;
- // initialPointsMethod uniformGrid;
- // initialPointsMethod bodyCentredCubic;
- // initialPointsMethod pointFile;
+ initialPointsMethod autoDensity;
+ // initialPointsMethod uniformGrid;
+ // initialPointsMethod bodyCentredCubic;
+ // initialPointsMethod pointFile;
- // Take boundbox of all geometry. Samples with this box. If too much
- // samples (due to target cell size) in box split box.
+
+ // Take boundbox of all geometry. Sample with this box. If too much
+ // samples in box (due to target cell size) split box.
autoDensityDetails
{
- // Number of refinement levels. Needs to be enough to pick up features
- // due to size ratio.
- minLevels 2;
- // Split box if ratio of min to max size larger than maxSizeRatio
+ // Initial number of refinement levels. Needs to be enough to pick
+ // up features due to size ratio. If not enough it will take longer
+ // to determine point seeding.
+ minLevels 4;
+ // Split box if ratio of min to max cell size larger than maxSizeRatio
maxSizeRatio 5.0;
// Per box sample 3x3x3 internally
sampleResolution 3;
@@ -175,6 +228,7 @@ initialPoints
uniformGridDetails
{
+ // Absolute cell size.
initialCellSize 0.0015;
randomiseInitialGrid yes;
randomPerturbationCoeff 0.02;
@@ -189,13 +243,25 @@ initialPoints
pointFileDetails
{
+ // Reads points from file. Still rejects points that are too
+ // close to the surface (minimumSurfaceDistanceCoeff) or on the
+ // wrong side of the surfaces.
pointFile "constant/internalDelaunayVertices";
}
}
+// Control size of voronoi cells i.e. distance between points. This
+// determines the target cell size which is used everywhere.
+// It determines the cell size given a location. It then uses all
+// the rules
+// - defaultCellSize
+// - cellSizeControlGeometry
+// to determine target cell size. Rule with highest priority wins. If same
+// priority smallest cell size wins.
motionControl
{
+ // Absolute cell size of back ground mesh. This is the maximum cell size.
defaultCellSize 0.1;
// Assign a priority to all requests for cell sizes, the highest overrules.
@@ -205,7 +271,11 @@ motionControl
{
}
- relaxationModel adaptiveLinear;
+ // Underrelaxation for point motion. Simulated annealing: starts off at 1
+ // and lowers to 0 (at simulation endTime) to converge points.
+ // adaptiveLinear is preferred choice.
+ // Points move by e.g. 10% of tet size.
+ relaxationModel adaptiveLinear; //rampHoldFall
adaptiveLinearCoeffs
{
@@ -213,28 +283,57 @@ motionControl
relaxationEnd 0.0;
}
+ // Output lots and lots of .obj files
objOutput no;
+ // Timing and memory usage.
timeChecks yes;
+ // Number of rays in plane parallel to nearest surface. Used to detect
+ // next closest surfaces. Used to work out alignment (three vectors)
+ // to surface.
+ // Note that only the initial points (from the seeding) calculate this
+ // information so if these are not fine enough the alignment will
+ // not be correct. (any points added during the running will lookup
+ // this information from the nearest initial point since it is
+ // expensive)
alignmentSearchSpokes 36;
+ // For each delaunay edge (between two vertices, becomes
+ // the Voronoi face normal) snap to the alignment direction if within
+ // alignmentAcceptanceAngle. Slightly > 45 is a good choice - prevents
+ // flipping.
alignmentAcceptanceAngle 48;
+ // How often to rebuild the alignment info (expensive)
sizeAndAlignmentRebuildFrequency 20;
+ // When to insert points. Not advisable change to
+ // these settings.
pointInsertionCriteria
{
+ // If edge larger than 1.75 target cell size
+ // (so tets too large/stretched) insert point
cellCentreDistCoeff 1.75;
+ // Do not insert point if voronoi face (on edge) very small.
faceAreaRatioCoeff 0.0025;
+ // Insert point only if edge closely aligned to local alignment
+ // direction.
acceptanceAngle 21.5;
}
+ // Opposite: remove point if mesh too compressed. Do not change these
+ // settings.
pointRemovalCriteria
{
cellCentreDistCoeff 0.65;
}
+ // How to determine the point motion. All edges got some direction.
+ // Sum all edge contributions to determine point motion. Weigh by
+ // face area so motion is preferentially determined by large faces
+ // (or more importantly ignore contribution from small faces).
+ // Do not change these settings.
faceAreaWeightModel piecewiseLinearRamp;
piecewiseLinearRampCoeffs
@@ -245,34 +344,95 @@ motionControl
}
+// After simulation, when converting to polyMesh, filter out small faces/edges.
+// Do not change. See cvControls.H
polyMeshFiltering
{
+ // Upper limit on the size of faces to be filtered.
+ // fraction of the local target cell size
filterSizeCoeff 0.2;
- mergeClosenessCoeff 1e-4;
+
+ // Upper limit on how close two dual vertices can be before
+ // being merged, fraction of the local target cell size
+ mergeClosenessCoeff 1e-9;
+
+ // To not filter: set maxNonOrtho to 1 (so check fails) and then
+ // set continueFilteringOnBadInitialPolyMesh to false.
continueFilteringOnBadInitialPolyMesh true;
+
+ // When a face is "bad", what fraction should the filterSizeCoeff be
+ // reduced by. Recursive, so for a filterCount value of fC, the
+ // filterSizeCoeff is reduced by pow(filterErrorReductionCoeff, fC)
filterErrorReductionCoeff 0.5;
+
+ // Maximum number of filterCount applications before a face
+ // is not attempted to be filtered
filterCountSkipThreshold 4;
+
+ // Maximum number of permissible iterations of the face collapse
+ // algorithm. The value to choose will be related the maximum number
+ // of points on a face that is to be collapsed and how many faces
+ // around it need to be collapsed.
maxCollapseIterations 25;
+
+ // Maximum number of times an to allow an equal faceSet to be
+ // returned from the face quality assessment before stopping iterations
+ // to break an infinitie loop.
maxConsecutiveEqualFaceSets 5;
+ // Remove little steps (almost perp to surface) by collapsing face.
surfaceStepFaceAngle 80;
+ // Do not collapse face to edge if should become edges
edgeCollapseGuardFraction 0.3;
+ // Only collapse face to point if high aspect ratio
maxCollapseFaceToPointSideLengthCoeff 0.35;
}
+// Generic mesh quality settings. At any undoable phase these determine
+// where to undo. Same as in snappyHexMeshDict
meshQualityControls
{
+ //- Maximum non-orthogonality allowed. Set to 180 to disable.
maxNonOrtho 65;
+
+ //- Max skewness allowed. Set to <0 to disable.
maxBoundarySkewness 50;
maxInternalSkewness 10;
+
+ //- 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 quality of the tet formed by the
+ // variable base point minimum decomposition triangles and
+ // the cell centre (so not face-centre decomposition).
+ // This has to be a positive number for tracking
+ // to work. Set to very negative number (e.g. -1E30) to
+ // disable.
+ // <0 = inside out tet,
+ // 0 = flat tet
+ // 1 = regular tet
minTetQuality 1e-30;
- minVol 0;
+
+ //- Minimum absolute face area. Set to <0 to disable.
minArea -1;
- minTwist 0.02;
+
+ //- Minimum face twist. Set to <-1 to disable. dot product of face normal
+ //- and face centre triangles normal
+ minTwist 0.001;
+
+ //- minimum normalised cell determinant
+ //- 1 = hex, <= 0 = folded or flattened illegal cell
minDeterminant 0.001;
+
+ //- minFaceWeight (0 -> 0.5)
minFaceWeight 0.02;
+
+ //- minVolRatio (0 -> 1)
minVolRatio 0.01;
+
+ //must be >0 for Fluent compatibility
minTriangleTwist -1;
}