Indirect unstructured hex-dominant mesh generation using tetrahedra recombination: new developments.

Arnaud Botella and Bruno Levy and Guillaume Caumon and M. Valencia. ( 2015 )
in: 35th Gocad Meeting - 2015 RING Meeting, ASGA

Abstract

This paper is an extented version of Botella et al. [2014] and Botella et al. [2015]. It presents an indirect method to generate a hex-dominant mesh conformal to 3D geological surfaces and well paths suitable for Finite-Element and Control-Volume Finite-Element simulations. By indirect, we mean that the method first generates an unstructured tetrahedral mesh whose tetrahedra are then merged into primitives (hexahedra, prisms and pyramids). More specifically, we focus on determining the optimal set of primitives that can be recombined from a given tetrahedral mesh. The tetrahedral mesh is generated using the workflow proposed by Botella et al. [2014]. In this paper, we make mesh generation algorithms more robust. Concerning the recombination stage, first we detect in the tetrahedral mesh all the feasible volumetric primitives using a pattern-matching algorithm [Botella et al., 2015]. Then, selecting the optimal set of primitives among the feasible ones can be formalized using an abstract graph representation as a maximum weighted independent set problem, known to be N P-Complete in the case of an arbitrary graph. We propose new heuristic optimizations using cograph completions to find a reasonable set of primitives. All the tetrahedra of each selected primitive are then merged to build the final unstructured hex-dominant mesh.

Download / Links

BibTeX Reference

@inproceedings{BotellaGM2015,
 abstract = { This paper is an extented version of Botella et al. [2014] and Botella et al. [2015]. It presents an indirect method to generate a hex-dominant mesh conformal to 3D geological surfaces and well paths suitable for Finite-Element and Control-Volume Finite-Element simulations. By indirect, we mean that the method first generates an unstructured tetrahedral mesh whose tetrahedra are then merged into primitives (hexahedra, prisms and pyramids). More specifically, we focus on determining the optimal set of primitives that can be recombined from a given tetrahedral mesh. The tetrahedral mesh is generated using the workflow proposed by Botella et al. [2014]. In this paper, we make mesh generation algorithms more robust. Concerning the recombination stage, first we detect in the tetrahedral mesh all the feasible volumetric primitives using a pattern-matching algorithm [Botella et al., 2015]. Then, selecting the optimal set of primitives among the feasible ones can be formalized using an abstract graph representation as a maximum weighted independent set problem, known to be N P-Complete in the case of an arbitrary graph. We propose new heuristic optimizations using cograph completions to find a reasonable set of primitives. All the tetrahedra of each selected primitive are then merged to build the final unstructured hex-dominant mesh. },
 author = { Botella, Arnaud AND Levy, Bruno AND Caumon, Guillaume AND Valencia, M. },
 booktitle = { 35th Gocad Meeting - 2015 RING Meeting },
 publisher = { ASGA },
 title = { Indirect unstructured hex-dominant mesh generation using tetrahedra recombination: new developments. },
 year = { 2015 }
}