【摘要】 入口利用层流速度型叠加二维和三维Tollmien-Schliting(T-S)波,应用动态亚格子模型、预处理技术以及高精度算法,采用大涡模拟(Large eddy simulation,LES)数值计算方法,对可压缩平板边界层空间模式的转捩机理及其拟序结构进行了研究。计算结果展示了T-S波经历线性、非线性发展阶段破碎形成发卡涡,最终演化成具有4个涡环的涡链结构的整个过程,并揭示了发卡涡涡腿并非完整对称及低速条带在涡环产生的位置不连续的现象,探讨了主流向涡与壁面相互作用诱导生成次流向涡的机理。更多还原

【Abstract】 The inlet boundary is specified by laminar Blasius similarity solution as the basic flow with imposed Tollmien-Schlichting(T-S)waves as the disturbances,the dynamic subgrid-scale model,the high order schemes and a preconditioned algorithm are used in the study of laminar-to-turbulent transition in a spatially developing boundary layer by large eddy simulation(LES).Simulation result exhibits the linear and nonlinear growth of T-S waves,the formation and evolution of hairpin vortex and multiple vortex rings with four ring-like vortexes,coupled with complex ejection/sweep movements and high/low speed streaks.Finally,the generation and development processes of secondary streamwise vortex are analyzed.更多还原