壁湍流相干结构和减阻控制机理  

Coherent structures and drag-reduction mechanism in wall turbulence

作　　者：许春晓[1] 

机构地区：[1]清华大学工程力学系,北京100084

出　　处：《力学进展》2015年第1期111-140,共30页Advances in Mechanics

基　　金：国家自然科学基金资助项目(11490551;11472154;11132005)

摘　　要：剪切湍流中相干结构的发现是上世纪湍流研究的重大进展之一,这些大尺度的相干运动在湍流的动力学过程中起重要作用,也为湍流的控制指出了新的方向.壁湍流高摩擦阻力的产生与近壁区流动结构密切相关,基于近壁区湍流动力学过程的减阻控制方案可以有效降低湍流的摩擦阻力,但是随着雷诺数的升高,这些控制方案的有效性逐渐降低.近年来研究发现,在高雷诺数情况下外区存在大尺度的相干运动,这种大尺度运动对近壁区湍流和壁面摩擦阻力的产生有重要影响,为高雷诺数湍流减阻控制策略的设计提出了新的挑战.该文将对壁湍流相干结构的研究历史加以简单的回顾,重点介绍近壁区相干结构及其控制机理、近年来高雷诺数外区大尺度运动的研究进展,在此基础上提出高雷诺数减阻控制研究的关键科学问题.The discovery of coherent structures in turbulent shear flows is one of the most important advances in turbulence research of the last century. These large-scale structures play important role in the physics of wall turbulence, and suggest a new direction for turbulence control. High skin friction in wall-bounded turbulent flows is closely associated with the coherent structures in the near-wall region. The control strategy based on the near-wall physics successfully achieves drag reduction, yet becomes less effective as the Reynolds num- ber increases. It was discovered recently that large-scale coherent motions exist in the outer layer of the high-Reynolds number wall turbulence. These motions have important influence on turbulence in the near-wall region and the skin friction, and bring new challenges to the control of turbulent flow at high Reynolds number. In the present paper, we briefly review the research history on coherent structures in wall turbulence, and mainly focus on dis- cussing the near-wall coherent structures and their control mechanism, the recent research developments on the large-scale motions in the outer region of high-Reynolds number wall turbulence, and the key issues concerning the drag-reduction control of the high-Reynolds number turbulent flows.

关 键 词：壁湍流 相干结构 减阻控制 

分 类 号：O357.5[理学—流体力学]