摘要
针对超声速边界层转捩问题,以五阶迎风和六阶对称紧致格式数值求解三维可压缩滤波Navier-Stokes方程,对马赫数4.5,雷诺数10000的空间发展超声速平板边界层的谐波扰动转捩问题进行了大涡模拟。时间推进采用紧致存储三阶Runge-Kutta方法,亚格子尺度模型为修正Smagorinsky涡粘性模型。通过入口叠加一对线性最不稳定第一模态斜波扰动的方法,得到了从线性/弱非线性扰动增长、交替Λ涡结构出现到演化为发卡涡的转捩过程;针对剪切层结构等现象,给出了该转捩拟序运动的详细讨论。比较显示,转捩结构及摩擦系数曲线等同理论分析吻合。
The spatial transition coherent structures of a supersonic flat-plate boundary layer at a free-stream Mach number 4.5 and a Reynolds number of 10000 based on free-stream velocity and inflow displacement thickness is studied through using a hybrid method of a fifth-order upwind compact difference and a sixth-order symmetric compact difference to numerically solve the three-dimensional compressible nondimensional Favre-filered Navier-Stokes equations. The compact storage third-order explicit Runge-Kutta method is applied for time-integration. The sub-grid scales are formulated according to the modified Smagorinsky eddy-viscosity model. Based on the linear stability theory, a pair of the most unstable oblique first mode disturbances is imposed on the inflow boundary. The obtained transition process is divided into several stages： the linear and weakly nonlinear growth of disturbance, the appearance of staggered A -vortex pattern, and the evolution of A -vortex into hairpin vortex. Moreover, the transition coherent motions, such as the shear layer structures, are discussed in detail. Present LES numerical results agree well with the relevant flat-plate theory.
出处
《宇航学报》
EI
CAS
CSCD
北大核心
2006年第3期498-502,共5页
Journal of Astronautics
基金
国家安全重大基础研究(51324)
关键词
超声速边界层
转捩
拟序结构
大涡模拟
Supersonic boundary layer
Transition
Coherent structure
Large eddy simulation
