通过比较间断Galerkin有限元方法(DGM)和有限体积方法(FVM),提出"静态重构"和"动态重构"的概念,进一步建立基于静动态"混合重构"算法的三阶DG/FV混合格式.在DG/FV混合格式中,单元平均值和一阶导数由DGM方法"动态重构",二阶导数利用FVM方法"静态重构";在此基础上,构造高阶多项式插值函数,得到三阶精度的DG/FV混合格式.将DG/FV混合格式推广应用于二维非结构网格,求解二维标量方程和Euler方程.典型算例数值实验表明,DG/FV混合格式达到了理想中的三阶精度.
With study of finite volume(FV) methods and discontinuous Galerkin(DG) method,"static reconstruction"and "dynamic reconstruction"are proposed for high-order numerical schemes.Based on the concept of"hybrid reconstruction",a new class of hybrid DG/FV schemes is presented for two-dimensional(2D) unstructured grids to solve the 2D conservation law,including 2D scalar equations and Euler equations.In the hybrid DG/FV schemes,lower-order derivatives of the piecewise polynomial are computed locally in a cell by a traditional DG method(called"dynamic reconstruction"),and the higher-order derivatives are re-constructed by the"static reconstruction"of the FV method by using lower-order derivatives in the cell and immediate neighbour cells.Typical 2D cases are given,and accuracy study is carried out.Numerical results show that the hybrid DG/FV scheme reaches desired order of accuracy.In addition,the hybrid DG/FV scheme saves great CPU time and memory compared with same order DG schemes.