阶梯形丁坝区明槽紊流脉动流速的空间相关结构  

Spatial correlation structure of turbulent flow velocity fluctuations of step-shaped spur dike area in open channel

作　　者：赵紫辰 钟亮[1,2] 葛晨曦[2] ZHAO Zi-chen;ZHONG Liang;GE Chen-xi(National Engineering Research Center for Inland Waterway Regulation,Chongqing Jiaotong University,Chongqing 400074,China;Key Laboratory of Hydraulic and Waterway Engineering of the Ministry of Education,Chongqing Jiaotong University,Chongqing 400074,China)

机构地区：[1]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 [2]重庆交通大学,水利水运工程教育部重点实验室,重庆400074

出　　处：《水运工程》2022年第11期145-151,159,共8页Port & Waterway Engineering

基　　金：重庆市基础科学与前沿技术研究项目(cstc2017jcyjAX0278)。

摘　　要：阶梯形丁坝在航道整治中应用广泛,脉动流速的空间相关结构是紊流相干结构的重要组成,可有效反映阶梯形丁坝区的流场特性。基于阶梯形丁坝区明槽紊流PIV流场测试资料,分析阶梯形丁坝区脉动流速空间自相关结构与互相关结构的分布特性,研究脉动流速空间相关结构沿主流、水深及槽宽方向的变化规律。结果表明:纵向脉动流速自相关系数C_(uu)与垂向脉动流速自相关系数C_(vv)均为正值;自相关系数在0.3~0.9区间内的等值线,其分布范围随着水深增加而减小,随着与丁坝距离的增大而增大;近坝区纵、垂向脉动流速互相关系数C_(uv)与垂、纵向脉动流速互相关系数C_(vu)云图在丁坝下游约一级丁坝坝长范围内出现基本对称的正负分区现象;一级丁坝附近C_(uv)及C_(vu)云图中相关性较强的等值线分布范围在近坝区较大而水槽中心较小;水槽中心附近,脉动流速空间互相关系数绝对值较大的等值线基本分布在二级丁坝上方,C_(uv)为正,C_(vu)为负。Step-shaped spur dike is widely used in channel regulation.As one of the important coherent structures of turbulence,the spatial correlation structure of velocity fluctuations can effectively reflect the flow field characteristics around step-shaped spur dike area.Based on PIV test data of turbulent flow of step-shaped spur dike area in open channel,the distribution characteristics of spatial auto-correlation and cross-correlation structure of velocity fluctuations in step-shaped spur dike area are analyzed,and the variation of two-point spatial correlation structures of velocity fluctuations along streamwise,wall-normal and spanwise are studied.The results show that the auto-correlation of the streamwise velocity fluctuations C_(uu) and the auto-correlation of the wall-normal velocity fluctuations C_(vv) are both positive.The value of the autocorrelation coefficient is in the interval of 0.3 to 0.9,the distribution range decreases with the increase of water depth,and increases with the increase of the distance from the step-shaped spur dike.The cloud map of the cross-correlation coefficient of streamwise and wall-normal velocity fluctuations C_(uv) and the cross-correlation coefficient of wall-normal and streamwise velocity fluctuations C_(vu) in the near dike area has a basically symmetrical positive and negative partition phenomenon within the length of the first-level spur dike downstream of the spur dike.The distribution range of contour lines with strong correlation in the cloud map of C_(uv) and C_(vu) near the first step-shaped spur dike is larger in the area near the dike and smaller in the center of the flume.Near the center of the flume,the contour lines with the larger absolute value of the spatial cross-correlation coefficient of the velocity fluctuations are basically distributed above the secondary spur dike,C_(uv) is positive,C_(vu) is negative.

关 键 词：阶梯形丁坝 明渠紊流 脉动流速 空间相关性 

分 类 号：TV143.5[水利工程—水力学及河流动力学] U617.9[交通运输工程—船舶及航道工程]