Abstract: The mesh elements can reach ten-millions for real engineering cases to simulate their flow field with CFD. The parallel technique is an effective way to reduce the computing time. Mesh adaptation coupled with flow information can dynamically optimize computing mesh and has been considered by NASA as a key technique to be urgently developed. Elements distribution optimization, surface points projection, and inner points matching are three essential techniques for hybrid mesh adaptation. In this study, parallel algorithms for these three techniques are established. First, the two-stage strategy, which is called uniqueness-then-identity, is proposed to obtain the parallel consistence for the process of elements distribution optimization. Next, based on the local surface fitting method, the entire parallel algorithm is developed for surface reconstruction and new physical points projection. Then, the half-parallel algorithm for inner points movement is devised to efficiently eliminate the overlapping of mesh elements. To increase the parallel efficiency of the sequent flow field calculation, the dynamic load balance method, based on parallel partitioning and mesh transferring methods, is developed, and the flow around a cylinder is simulated to verify the dynamic load balance method. Finally, mesh refinement with adaptation for a delta-wing was adopted to test the parallel efficiency of the adaptation system. Numerical results show that the parallel efficiency of the hybrid mesh adaptation system is high enough and the total time cost is less than 1% of the flow solver.

Key words: hybrid mesh, mesh adaptation, parallel algorithms, parallel consistence, dynamic load balance, parallel efficiency