Free-surface air entrainment in open-channel flows  

作　　者：WEI WangRu XU WeiLin DENG Jun TIAN Zhong ZHANG FaXing 

机构地区：[1]State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610065, China

出　　处：《Science China(Technological Sciences)》2017年第6期893-901,共9页中国科学（技术科学英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant No. 51379138);the National Basic Research Program of China (“973” Project) (Grant No. 2013CB035905)

摘　　要：In hydraulic engineering,free-surface aeration is a natural phenomenon occurring in smooth channel flows.In self-aerated flows,a key aspect that has not yet been well understood is the formation mechanism of free-surface air entrainment.In this research,the process of free-surface entrapped deformation is analyzed theoretically and the critical radius of curvature for air entrainment is obtained,affected by flow mean velocity and depth.When the severity of local free-surface deformation exceeds the critical condition,the entrapped free surface encounters closure in the unstable deformation movement process,resulting in air entrainment.This inference agrees well with observed experimental results that are obtained from the processes of surface entrapped deformation and air entrainment captured by a high-speed camera-based data acquisition system.This agreement indicates that self-aeration occurs in low-velocity open-channel flows.It is also confirmed that free-surface turbulent deformation provides a mechanism for air entrainment.

关 键 词：hydraulic engineering self-aeration turbulence free surface open-channel flows 

分 类 号：TV133[水利工程—水力学及河流动力学]