非结构网格上针对间断有限元方法的初值重映流场收敛加速技术

SOLUTION REMAPPING TECHNIQUE TO ACCELERATE FLOW CONVERGENCE FOR DISCONTINUOUS GALERKIN METHODS ON UNSTRUCTURED MESHES

给出一种非结构网格上针对间断有限元方法的初值重映流场收敛加速技术框架,以提高气动优化过程中间断有限元方法的收敛速度,减少优化过程所需时间.在保持网格拓扑结构不变的前提下,通过从给定的参考单元到物理域上每个网格单元的一一映射,在不同外形的网格上相应单元之间建立局部的一一对应关系;每次更新外形时,将当前外形的数值解重映到新外形的网格上作为初值,以加快间断有限元方法的收敛速度.将该技术应用于三角形网格上的翼型优化设计问题,取得了很好的效果,对于三阶间断有限元方法能够减少超过70%的计算时间.

A framework of the solution remapping technique on unstructured meshes is proposed to accelerate flow convergence for the discontinuous Galerkin(DG)methods in aerodynamic shape optimization.A local one-to-one correspondence between the meshes of different shapes is established by the one-to-one mappings from a given reference cell to each grid cell in the physical domain if the mesh topology is preserved in the optimization process.Then when the shape is updated,the solution of the current shape is remapped to the mesh of the new shape as the initial value to accelerate the convergence of the DG solver.The proposed framework is implemented in the airfoil design problem on triangular meshes.Numerical experiments show that more than 70%of the computational time can be saved with a third-order DG solver.