AUTOMATIC GENERATOR OF UNSTRUCTURED POLYHEDRAL MESHES ON THE BASE OF TETRAHEDRAL MESHES WITH PRISMATIC LAYERS
N. V. Popova
VANT. Ser.: Mat. Mod. Fiz. Proc 2021. Вып.3. С. 70-83.
In the numerical simulation of fluid flows described by Eulerian, or Navier-Stokes equations the computational mesh generation is performed prior to the solution of basic equations and analysis of results. The paper describes an automatic generator of unstructured meshes consisting of arbitrarily-shaped polyhedrons on the base of partitioning tetrahedrons and prisms. A 3D mesh is generated beginning from the boundaries of a surface triangular mesh approximating an arbitrary closed computational domain. There are two main stages of the process: generation of a primary isotropic tetrahedral mesh with prismatic layers and generation of a secondary polyhedral mesh using a hybrid scheme. To build a prismatic mesh, the method of stretching a surface triangular mesh at a given distance along normals is used. Intermediate nodes are calculated according to the given distribution law. To build a tetrahedral mesh, the method of a moving front is used. Local areas of concentrated, or coarsened cells are provided for. The transformation into a polyhedral mesh is primarily performed using the centroid dual scheme and the near-surface transformation in regions with specific geometric features is performed using the median dual scheme. Classification of the primary mesh nodes and the corresponding ways of generating polyhedral cells are described. The mesh generation result is presented by the example of a joining piece of pipeline. The automatic mesh generation is used in the preprocessor of the "Logos" software package for engineering analysis and supercomputer simulation. Keywords: "Logos" software package, preprocessor, unstructured meshes, arbitrarily-shaped polyhedrons, a tetrahedral mesh, a prismatic layer, Delaunay triangulation with restrictions, mediаn dual scheme, centroid dual scheme.
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English
