Join GitHub today
GitHub is home to over 28 million developers working together to host and review code, manage projects, and build software together.Sign up
Analyze the quality of unstructured anisotropic meshes for aerodynamics
Fetching latest commit…
Cannot retrieve the latest commit at this time.
|Type||Name||Latest commit message||Commit time|
|Failed to load latest commit information.|
What This Tool Does This code analyzes a volume mesh, checking for topological validity, positive cell volumes, size ratio for adjacent cells, dihedral angles, and distortion of quadrilateral faces. Also, mesh length scale perpendicular to the surface and along the surface are assessed. Finally, if a Pointwise nmb file and the Pointwise GEODE library are available, the distance from mesh points that should be on the geometry to the actual geometry is assessed. Much of the code is multi-threaded for speed (since the assessments are embarassingly parallel, this is easy to do safely). Also, to the extent possible, the code operates on data streamed from disk rather than reading the entire mesh into memory at once. The topology checks are the biggest user of memory, because those checks work by trying to match up the two copies of a triangular or quadrilateral face. Before beginning this process, an estimate of required memory is done. If this requirement is too large a fraction of machine memory, a slower, less memory intensive variant of the algorithm is invoked. Mesh I/O is done using a plug-in architecture. See Mesh-Readers.txt for more information. How to Build This package uses an autoconf-based build system. You can run autoconf if you wish, but this isn't strictly necessary, as a configure script is also included. Options to configure, in addition to the standard ones: --enable-debug builds without optimization and with debugging enabled. --with-geode=/dir/for/Pointwise/GEODE/kernel --with-geode-arch=arch The Pointwise GEODE kernel, if available, can be used to check the projection of surface mesh points to the actual geometry (see below for usage). These two options must be supplied together. Include files for GEODE must be in /dir/for/Pointwise/GEODE/kernel/include, and GEODE libraries must be in /dir/for/Pointwise/GEODE/kernel/lib/arch. After you run configure, run make (and optionally make install). How to Run analyzeVolMesh requires a file type indicator and a base file name. The file type indicator can be vtk for a legacy (ASCII) file, or ugrid for UGRID file. For UGRID files, the UGRID file type specifier (b8, lb8, etc) must be supplied as the last argument. For example, analyzeVolMesh vtk myMesh This will read a VTK file called myMesh.vtk analyzeVolMesh ugrid myOtherMesh b8 This will read a UGRID file called myOtherMesh.b8.ugrid. At this point, only four-byte integers are handled in UGRID files, even though there are variants of the UGRID format that provide eight byte integers. analyzeVolMesh ugrid myOtherMesh -nmb myGeometry.nmb b8 Same as above, but also checks distance from surface mesh points from the geometry. Output The mesh analyzer produces four files: 1. A VTK file (legacy ASCII format) that gives information associated with each surface point: - The distance to the nearest interior point - The distance to the nearest point on the surface - The projected distance to the geometry defined in the .nmb file (if specified) - The surface ID in the geometry onto which each point is projected. 2. A file, readable by gnuplot, that quantifies non-planarity of quadrilaterals in the mesh. (...-distort.dat). 3. A file, readable by gnuplot, that gives histograms of size ratio for adjacent cells, arranged by the types of cells (tet-tet size ratio is separate from tet-prism size ratio, and so on). This file also includes the total number of faces separating each pair of cell types. Columns are labeled in the file. 4. A file, readable by gnuplot, that gives histograms of dihedral and face angles. In the directories gnuplot-scripts and python-scripts, you will find the gnuplot and paraview script files used to produce the figures in the 2018 AIAA SciTech paper analyzing meshes from the First AIAA Geometry and Mesh Generation Workshop / Third AIAA High-Lift Prediction Workshop. Reference For more information, including mathematical formulations of various quantities computed by the code and mentioned above, please see: Carl F. Ollivier Gooch. "Analysis of Unstructured Meshes from GMGW-1 / HiLiftPW-3", 2018 AIAA Aerospace Sciences Meeting, AIAA SciTech Forum, (AIAA 2018-0132) https://doi.org/10.2514/6.2018-0132. A PDF of this paper is included in the docs folder. If you find this tool helpful and use it in your own work, please cite this paper, as noted above.