From f983ffbdaf3811ed23f1640a26bf7fe923d3c766 Mon Sep 17 00:00:00 2001
From: mattijs <mattijs>
Date: Thu, 16 Jun 2011 12:53:13 +0100
Subject: [PATCH] ENH: cvMeshDict: added comment
---
.../mesh/generation/cvMesh/cvMeshDict | 362 ++++++++++++++++++
1 file changed, 362 insertions(+)
create mode 100644 applications/utilities/mesh/generation/cvMesh/cvMeshDict
diff --git a/applications/utilities/mesh/generation/cvMesh/cvMeshDict b/applications/utilities/mesh/generation/cvMesh/cvMeshDict
new file mode 100644
index 00000000000..2896ab85107
--- /dev/null
+++ b/applications/utilities/mesh/generation/cvMesh/cvMeshDict
@@ -0,0 +1,362 @@
+/*--------------------------------*- C++ -*----------------------------------*\
+| ========= | |
+| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
+| \\ / O peration | Version: dev |
+| \\ / A nd | Web: www.OpenFOAM.com |
+| \\/ M anipulation | |
+\*---------------------------------------------------------------------------*/
+
+FoamFile
+{
+ version 2.0;
+ format ascii;
+ class dictionary;
+ object cvMeshDict;
+}
+
+// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
+
+// Impoprtant:
+// -----------
+// Any scalar with a name <name>Coeff specifies a value that will be implemented
+// as a faction of the local target cell size
+// Any scalar with a name <name>Size specifies an absolute size.
+
+
+// Geometry. Definition of all surfaces. All surfaces are of class
+// searchableSurface.
+// Surfaces need to be (almost) closed - use closedTriSurfaceMesh
+// if they are not topologically closed. Surfaces need to be oriented so
+// the space to be meshed is always on the inside of all surfaces. Use e.g.
+// surfaceOrient.
+geometry
+{
+ flange.obj
+ {
+ type triSurfaceMesh;
+ }
+}
+
+
+// See cvControls.H
+surfaceConformation
+{
+ // Volume of surfaces that is inside mesh.
+ locationInMesh (0 0 0);
+
+ // 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;
+
+ // See cvControls.H
+ featurePointExclusionDistanceCoeff 0.4;
+
+ // See cvControls.H
+ featureEdgeExclusionDistanceCoeff 0.2;
+
+ // Optimisation: do not check for surface intersection (of dual edges)
+ // for points near to surface.
+ surfaceSearchDistanceCoeff 2.5;
+
+ // Do not conform to small protrusions. These get 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.
+ 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
+ // if near to feature edge.
+ edgeSearchDistCoeff 1.1;
+ surfacePtReplaceDistCoeff 0.5;
+ }
+
+ iteration
+ {
+ edgeSearchDistCoeff 1.25;
+ surfacePtReplaceDistCoeff 0.7;
+ }
+
+ // Stop either at maxIterations or if the number of surface pokes
+ // is very small (iterationToInitialHitRatioLimit * initial number)
+ maxIterations 15;
+
+ iterationToInitialHitRatioLimit 0.001;
+ }
+
+ // Final (at endTime) controls
+ fineConformationControls
+ {
+ initial
+ {
+ edgeSearchDistCoeff 1.1;
+ surfacePtReplaceDistCoeff 0.5;
+ }
+
+ iteration
+ {
+ edgeSearchDistCoeff 1.25;
+ surfacePtReplaceDistCoeff 0.7;
+ }
+
+ maxIterations 15;
+
+ iterationToInitialHitRatioLimit 0.001;
+ }
+
+ // Geometry to mesh to
+ geometryToConformTo
+ {
+ flange.obj
+ {
+ featureMethod extendedFeatureEdgeMesh;
+ extendedFeatureEdgeMesh "flange.extendedFeatureEdgeMesh";
+ }
+ }
+
+ // Independent features
+ additionalFeatures {}
+}
+
+
+initialPoints
+{
+ // Do not place point closer than minimumSurfaceDistanceCoeff
+ // to the surface. Is fraction of local target cell size (see below)
+ minimumSurfaceDistanceCoeff 0.55;
+
+ //initialPointsMethod densityWeightedStochastic;
+ initialPointsMethod hierarchicalDensityWeightedStochastic;
+ // 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.
+ hierarchicalDensityWeightedStochasticDetails
+ {
+ // Number of refinement levels. Needs to be enough to pick up features
+ // due to size ratio.
+ minLevels 4;
+ // Split box if ratio of min to max size larger than maxSizeRatio
+ maxSizeRatio 5.0;
+ // Per box sample 7x7x7 internally
+ sampleResolution 7;
+ // Additionally per face of the box sample 5x5
+ surfaceSampleResolution 5;
+ }
+
+ densityWeightedStochasticDetails
+ {
+ // Volume of space to be meshed. Use surfaceInertia.
+ totalVolume 1.56e-05;
+ }
+
+ uniformGridDetails
+ {
+ // Absolute cell size.
+ initialCellSize 0.0015;
+ randomiseInitialGrid yes;
+ randomPerturbationCoeff 0.02;
+ }
+
+ bodyCentredCubicDetails
+ {
+ initialCellSize 0.0015;
+ randomiseInitialGrid no;
+ randomPerturbationCoeff 0.1;
+ }
+
+ 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
+ defaultCellSize 0.00075;
+
+ // Assign a priority to all requests for cell sizes, the highest overrules.
+ defaultPriority 0;
+
+ cellSizeControlGeometry
+ {
+ ref7_outside
+ {
+ // optional name of geometry
+ surface ref7;
+ priority 1;
+ mode outside;//inside/bothSides
+ cellSizeFunction linearDistance;
+
+ // Vary from surfaceCellSize (close to the surface) to
+ // distanceCellSize (further than 'distance')
+ linearDistanceCoeffs
+ {
+ surfaceCellSize 1e-5; // absolute size
+ distanceCellSize $defaultCellSize;
+ distance 1.0;
+ }
+ }
+
+ tunnel_APPROACH_INLET.obj
+ {
+ priority 1;
+ mode bothSides;
+ cellSizeFunction surfaceOffsetLinearDistance;
+ // Constant within a certain distance then linear fade away.
+ // Good for layers.
+ surfaceOffsetLinearDistanceCoeffs
+ {
+ surfaceCellSize $ref4_size;
+ distanceCellSize $defaultCellSize;
+ surfaceOffset 0.512;
+ totalDistance $tunnel_totalDistance;
+ }
+ }
+ }
+
+ // Underrelaxation for point motion. Simulated annealing: starts off at 1
+ // and lowers to 0 (and simulation endTime) to converge points.
+ // adaptiveLinear is preferred choice.
+ // Points move by e.g. 10% of tet size.
+ relaxationModel adaptiveLinear;
+
+ adaptiveLinearCoeffs
+ {
+ relaxationStart 1.0;
+ relaxationEnd 0.0;
+ }
+
+ // 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. Keep at 48.
+ alignmentAcceptanceAngle 48;
+
+ // How often to rebuild the alignment info
+ sizeAndAlignmentRebuildFrequency 20;
+
+ // When to insert points. If edge larger than 1.75 target cell size
+ // (so tets too large/stretched) insert point. Do not change these
+ // settings.
+ pointInsertionCriteria
+ {
+ 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. Weight by
+ // face area so motion is preferentially determined by large faces
+ // (more importantly ignore contribution from small faces).
+ // Do not change these settings.
+ faceAreaWeightModel piecewiseLinearRamp;
+
+ piecewiseLinearRampCoeffs
+ {
+ lowerAreaFraction 0.5;
+ upperAreaFraction 1.0;
+ }
+}
+
+
+// After simulation. Do not change. See cvControls.H
+polyMeshFiltering
+{
+ filterSizeCoeff 0.2;
+ mergeClosenessCoeff 1e-4;
+
+ // To not filter: set maxNonOrtho to 1 (so check fails) and then
+ // set continueFilteringOnBadInitialPolyMesh to false.
+ continueFilteringOnBadInitialPolyMesh true;
+ filterErrorReductionCoeff 0.5;
+ filterCountSkipThreshold 4;
+ maxCollapseIterations 25;
+ 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;
+}
+
+
+meshQualityControls
+{
+ maxNonOrtho 65;
+ maxBoundarySkewness 50;
+ maxInternalSkewness 10;
+ maxConcave 80;
+ minTetQuality 1e-30;
+ minVol 0;
+ minArea -1;
+ minTwist 0.02;
+ minDeterminant 0.001;
+ minFaceWeight 0.02;
+ minVolRatio 0.01;
+ minTriangleTwist -1;
+}
+
+
+// ************************************************************************* //
--
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