No abstract

No abstract

Summary High‐Performance Computing (HPC) systems and Computational Fluid Dynamics (CFD) have made significant progress in recent years; however, as the basis of the large‐scale parallel computing, the massive grid generation of billions of cells has become a bottleneck problem. In this study, a parallel grid generation technique is proposed to generate large‐scale mixed grids with arbitrary cell types and scales. The basic idea of our method is analogous to the global mesh refinement technique. An initial coarse grid with arbitrary cell types is regarded as a background mesh which is partitioned into subzones, and subzones are assigned onto different CPU cores. After the cells and faces in each subzone are split, the inserted new points of the solid wall are projected onto the original CAD entities to preserve the geometry accurately. Finally, the tangled cells caused by the projection in the boundary layer are untangled by a local Radial Basis Function mesh deformation technique. Furthermore, a parallel partition approach and an efficient wall distance computing technique for massive grids are developed also to shorten the preprocessing time. The tests show that the preprocessing efficiency has been increased by two or three orders compared with traditional methods. Billions of grids are generated for the AIAA JSM high‐lift model and the Chinese CHN‐T1 transport model to test the ability of the parallel grid generation technique. The maximum scale up to 19 billion mixed elements is generated using 16 384 CPU cores in parallel, and the mesh quality is acceptable for CFD simulations.

No abstract

With the growing computing power of high-performance computers, efficient parallel algorithms are becoming increasingly important in the development of Computational Fluid Dynamics(CFD). This research presents a novel parallel strategy based on asynchronous and package communication. This strategy tries to enhance the performance of large-scale computation for realistic complex geometry. The new strategy aggregates all communications and only requires communication once at each iteration step. Convergence of the new strategy is also proved and validated. Three numerical experiments demonstrates the exceptional parallel performance of the novel strategy in simulating complex geometry. When the number of CPU cores approach 26 thousand, strong scale parallel efficiency still remains at 74% based on 10.5 billion mesh elements. With 179,200 CPU cores and 10 billion mesh elements, weak scale parallel efficiency maintains at 90%. This research demonstrates that large-scale parallel computation can be applied efficiently in numerical simulation of a complex aircraft.