743dea87d2
terms of the local barycentric coordinates of the current tetrahedron, rather than the global coordinate system. Barycentric tracking works on any mesh, irrespective of mesh quality. Particles do not get "lost", and tracking does not require ad-hoc "corrections" or "rescues" to function robustly, because the calculation of particle-face intersections is unambiguous and reproducible, even at small angles of incidence. Each particle position is defined by topology (i.e. the decomposed tet cell it is in) and geometry (i.e. where it is in the cell). No search operations are needed on restart or reconstruct, unlike when particle positions are stored in the global coordinate system. The particle positions file now contains particles' local coordinates and topology, rather than the global coordinates and cell. This change to the output format is not backwards compatible. Existing cases with Lagrangian data will not restart, but they will still run from time zero without any modification. This change was necessary in order to guarantee that the loaded particle is valid, and therefore fundamentally prevent "loss" and "search-failure" type bugs (e.g., 2517, 2442, 2286, 1836, 1461, 1341, 1097). The tracking functions have also been converted to function in terms of displacement, rather than end position. This helps remove floating point error issues, particularly towards the end of a tracking step. Wall bounded streamlines have been removed. The implementation proved incompatible with the new tracking algorithm. ParaView has a surface LIC plugin which provides equivalent, or better, functionality. Additionally, bug report <https://bugs.openfoam.org/view.php?id=2517> is resolved by this change.
79 lines
2.9 KiB
C++
79 lines
2.9 KiB
C++
/*--------------------------------*- C++ -*----------------------------------*\
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| ========= | |
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| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
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| \\ / O peration | Version: plus |
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| \\ / A nd | Web: www.OpenFOAM.com |
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| \\/ M anipulation | |
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\*---------------------------------------------------------------------------*/
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FoamFile
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{
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version 2.0;
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format ascii;
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class dictionary;
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object meshQualityDict;
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}
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// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
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//- Maximum non-orthogonality allowed. Set to 180 to disable.
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maxNonOrtho 65;
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//- Max skewness allowed. Set to <0 to disable.
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maxBoundarySkewness 20;
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maxInternalSkewness 4;
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//- Max concaveness allowed. Is angle (in degrees) below which concavity
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// is allowed. 0 is straight face, <0 would be convex face.
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// Set to 180 to disable.
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maxConcave 80;
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//- Minimum pyramid volume. Is absolute volume of cell pyramid.
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// Set to a sensible fraction of the smallest cell volume expected.
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// Set to very negative number (e.g. -1E30) to disable.
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minVol 1e-13;
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//- Minimum quality of the tet formed by the face-centre
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// and variable base point minimum decomposition triangles and
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// the cell centre. Set to very negative number (e.g. -1E30) to
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// disable.
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// <0 = inside out tet,
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// 0 = flat tet
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// 1 = regular tet
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minTetQuality 1e-15;
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//- Minimum face area. Set to <0 to disable.
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minArea -1;
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//- Minimum face twist. Set to <-1 to disable. dot product of face normal
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// (itself the average of the triangle normals)
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// and face centre triangles normal
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minTwist 0.02;
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//- Minimum normalised cell determinant. This is the determinant of all
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// the areas of internal faces. It is a measure of how much of the
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// outside area of the cell is to other cells. The idea is that if all
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// outside faces of the cell are 'floating' (zeroGradient) the
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// 'fixedness' of the cell is determined by the area of the internal faces.
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// 1 = hex, <= 0 = folded or flattened illegal cell
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minDeterminant 0.001;
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//- Relative position of face in relation to cell centres (0.5 for orthogonal
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// mesh) (0 -> 0.5)
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minFaceWeight 0.05;
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//- Volume ratio of neighbouring cells (0 -> 1)
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minVolRatio 0.01;
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//- Per triangle normal compared to that of preceding triangle. Must be >0
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// for Fluent compatibility
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minTriangleTwist -1;
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//- If >0 : preserve cells with all points on the surface if the
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// resulting volume after snapping (by approximation) is larger than
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// minVolCollapseRatio times old volume (i.e. not collapsed to flat cell).
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// If <0 : delete always.
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//minVolCollapseRatio 0.1;
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// ************************************************************************* //
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