Research On Two-Dimensional Delaunay Mesh Generation And Its Parallelization

Mesh generation is the key pre-process and one of main performance bottlenecks of numerical simulation.The widespread availability of parallel machines with large memory,solvers that can harness the power of these machines,and the desire for large-scale engineering and scientific computing has lead to a steady increase in the research of parallel mesh generation.The quest for mesh generation and its parallelization,three inter-related problems on mesh generation are discussed,i.e.two-dimensional Delaunay mesh generation,two-dimensional Delaunay parallel mesh generation and mesh partitioning.Firstly,the characteristics of the Delaunay triangulation and Voronoi diagram are studied in order to build the two-dimensional Delaunay mesh generator,named DM2D,which used the Bowyer-Waston point insertion kernel.Additionally,some optimization methods for the boundary recovery and mesh optimization problems,including diagonal swap,removing bad elements and elastic smoothing,is effectively.Secondly,according to the domain-defining grid method proposed by Lohner,and introducing the domain decomposition idea and using the mesh partitioning strategy.A twodimensional general parallel mesh generator,named PDM2D,is developed by combining the framework with DM2D,which could generate more than one hundred thousand of elements in the parallel computers with 16cores,256GB size resources.Thirdly,for mesh partitioning problem,a multi-level reactive tabu search method M-CGT was designed with the multi-level partitioning method of mpmetis algorithm in Metis and Kalayci's reactive-randomized tabu search.In order to make full use of the advantages of multilevel algorithm,the cluster-based coarsening strategy is applied to the coarsening phase,the reactive tabu search algorithm and greedy algorithm are applied to the initial partitioning phase and uncoarsening phase.It can reduce the size of the graph faster,while ensuring better partitioning.Finally,the basics of computer graphics and OpenCASCADE technology based on OpenGL are studied in order to build the two-dimensional Delaunay mesh generator DM2D and its parallelization PDM2D.Taking OpenCASCADE modules as the starting point,a reasonable in-out data interface to connect with CAD modeling software was designed.Based on visual real-time display of operation results,the operation difficulty was reduced.Then,parallel mesh generation was realized to improve the efficiency of mesh generation.Through following the track of the mesh quality measure,the mesh quality could be checked,and the mesh with low quality was timely modified to ensure that the obtained mesh can complete the numerical simulation process and achieve the predetermined precision.