可压缩槽道流动的大涡模拟研究

Large Eddy Simulation of Compressible Channel Flow

可压缩湍流边界层是高速飞行器研究面临的基础科学问题,对其流动机理的认识对于高速飞行器气动力热设计具有重要意义。采用大涡模拟方法对可压缩槽道流动进行了数值模拟研究,并基于Favré过滤建立了适用于可压缩流动的大涡模拟方法,将混合亚格子模型延拓到了动态形式,形成了适用于可压缩流动的动态混合模型。通过分析亚格子模型、网格疏密和计算格式对数值模拟结果的影响,结果表明所建立的大涡模拟方法在较少网格数下能够获得可靠的计算结果。数值模拟还获得了可压缩槽道流动时间转捩的过程,捕捉到了大尺度旋涡结构和近壁速度条带结构的演化过程。

The compressible turbulent boundary layer is a basic scientific problem for the research of high-speed aircraft,and the understanding of its flow mechanism is of great significance for the aerodynamic and thermal design of high-speed aircraft.Large eddy simulation(LES)of compressible channel flow is performed.The LES method for compressible flow is established based on Favréfilter,and a dynamic mixed subgrid-scale(SGS)model for compressible flow is formed by extending the mixed SGS model to the dynamic form.Through the analysis of SGS model,grid density and numerical scheme,the LES method established in the present work can obtain reliable results with fewer grids.The numerical results also show the transition process of the compressible channel flow,and capture the evolution process of the large-scale vortices and the near-wall velocity streaks.