可压流数值模拟中当地DFD方法的改进和应用  

Improvement and application of the local domain-free discretization method for numerical simulation of compressible flows

作　　者：周春华[1] 

机构地区：[1]南京航空航天大学空气动力学系,南京210016

出　　处：《计算力学学报》2010年第5期874-880,共7页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金(10772083)资助项目

摘　　要：阐述了求解守恒型Euler方程的当地DFD(Domain-Free Discretization)方法的改进和应用。DFD离散策略的核心,是解域内点上控制方程的离散形式可与解域外的一些点相关。通过边界附近解的近似形式,外部相关点上的流动变量值得到确定并强加相应的边界条件。与最初的当地DFD方法不同,在解的近似形式构建中,采用了CCST技术(Curvature-Corrected Symmetry Technique),因此外部相关点上的密度和切向速度分别由等熵和等总焓关系确定。空间离散采用Galerkin有限体积格式。最后,给出了固定和运动物体可压缩绕流的数值模拟结果,以验证改进的当地DFD方法的可靠性和数值解精度的提高。This paper presents the improvement and application of the local domain-free discretization（DFD）method to solve the Euler equations in conservative form.The key of the discretization strategy of DFD is that the discrete form of governing equations at an interior point may involve some points outside the solution domain.By the approximate form of solution near the boundary,the flow variables at the exterior dependent points can be evaluated,and boundary conditions can also be imposed at the same time.Being different from the original local DFD,the Curvature-Corrected Symmetry Technique（CCST）is introduced in the construction of the approximate form of solution,and therefore the density and the velocity component tangential to the body,at the exterior dependent points,are determined respectively from the constant-entropy and constant-total-enthalpy relations.The Galerkin finite volume method is used for spatial discretization in the local DFD.Some numerical results for compressible flows over fixed and moving bodies are presented to validate the improvement in accuracy and the applicability of the present local DFD method.

关 键 词：边界非协调类方法 边界条件 运动边界 可压缩流动 有限体积法 

分 类 号：O246[理学—计算数学] V211.3[理学—数学]