STUDY OF LARGE-SCALE DYNAMICS EMANATED IN COMPLEX TURBUBLENT FLOWS

研究在固体壁面附近发展的湍流，通常称为壁面湍流，是湍流学的一个重要方面。本文研究了湍流壁面剪切流动的大尺度动力学，其中涡旋运动如发夹包的形成组织和相干结构的分支组织是必不可少的。采用空间演化的直接数值模拟方法，研究了壁面湍流发散的大尺度动力学。动力学归因于新的甚至旧的层次结构不稳定结构产生的抬升的低速条纹。

The study of turbulence developing close to solid walls, usually referred to as wall turbulence is one of the most important aspects of turbulence. In this study, large-scale dynamics in the turbulent wall shear flows are investigated, where the vortex motion such as the hairpin packet formation organization and ramifications of the organization of coherent structure is essential. Using spatially evolving direct numerical simulations, the large-scale dynamics of wall turbulence emanation is studied. The dynamics attributes to the new and even older hierarchy unstable structures generated by the lifted-up low-speed streaks.