明渠湍流发夹涡包形成及湍动能分布特性(摘要)

张鹏1，2，杨胜发1，2，胡江1，2，田蜜1，2，李文杰1，2，陈阳1，2

(1.重庆交通大学河海学院,重庆　400074；2.重庆交通大学国家内河航道整治工程技术研究中心，重庆　400074)

【摘　要】　湍流结构是湍流运动研究中最为基础的问题。为了解明渠湍流结构相互作用的动力演变关系，本文采用高频高分辨率粒子成像测速系统对发展的明渠湍流进行纵剖面二维流速矢量场进行测量，对发夹涡及发夹涡包结构与高低速流团的动力演变关系以及发夹涡结构内部的湍动能分布特性进行分析。结果表明:发夹涡及发夹涡包结构可以由高低速流团相互作用而产生;发夹涡涡核只位于高低速流团的交界区域。近壁区发夹涡结构的喷射(Q2)过程为产生湍动能的主要区域，而湍动能耗散主要集中在高低速流团的交界区域。明渠湍流近壁区为湍动能的主要产生与耗散的区域。

【关键词】　明渠湍流；发夹涡；发夹涡包；强剪切层；湍动能

The Formation of Hairpin Packet and Distribution of Turbulent Kinetic Energy in Turbulent Open Channel Flow

ZHANG Peng1，2,YANG Shengfa1，2,HU Jiang1，2,TIAN Mi1，2,LI Wenjie1，2,CHEN Yang1，2

(1.School of River &Ocean Engineering,Chongqing Jiaotong University,Chongqing　400074;2.National Inland Waterway Regulation Engineering Research Center,Chongqing Jiaotong University,Chongqing　400074)

Abstract:Turbulence structure is the most fundamental problem in turbulent flow research.To understand the dynamic evolution of interaction between the high-speed flow mass and hairpin vortices,the high velocity and high-resolution particle imaging velocity measurement system is used to measure the 2D velocity field of open channel.The dynamic evolution of high and low speed flow mass and the turbulent kinetic energy distribution of hairpin vortex structure are analyzed.The results show:Hairpin vortex and hairpin vortex packet can be generated by the interaction between high and low speed flow mass.The core of hairpin vortex is located only at the junction of high and low speed flow mass.The main region for generating turbulent kinetic energy is a second-quadrant ejection event near wall.Turbulent energy dissipation is mainly concentrated in the junction of high and low flow mass.The near-wall region of the open channel is the main generation and dissipation region of the turbulent kinetic energy.

Key words:Turbulent Flow;Hairpin Vortex;Hairpin Packet;Shear Zone;Turbulent Kinetic Energy