摘要
我国沿海沿江洄游性鱼类众多,单一式鱼道难以满足鱼类不同溯游习性的要求。迄今,人们对单一式鱼道研究较多,而对组合式鱼道仅限于数值模拟工作,试验研究几乎是空白。本文对凹口堰-矩形中孔-竖缝组合式鱼道的紊流结构进行了较为系统的试验研究。采用声学多普勒测速仪(ADV)量测了鱼道水池内各点的三维瞬时流速,分析了组合式鱼道的流动特征、时均流速、紊动强度、雷诺应力、频谱特性、相关函数及紊动尺度。试验研究结果表明:与单一式鱼道比较,组合式鱼道水流具有显著的三维流动结构;纵向流速在水平面上存在明显峰值区,横向流速和垂向流速显示在横断面上存在旋涡区;在竖缝壁面射流与孔口射流汇聚区,纵向、横向及垂向紊动强度均较大,合并后则逐渐减小;雷诺应力峰值区主要出现在多股射流交汇区;纵向脉动能量主频峰值大小为孔口>凹口堰>竖缝;纵向脉动流速表现出随时间的相关性,并有凹口堰>孔口>竖缝,且沿程波动周期延长;积分尺度和微分尺度显示涡旋结构与组合式鱼道的流区有关。
A variety of migratory fish species inhabit China’s seas and rivers, and it is difficult for a single fishway to meet the requirements of different swimming behaviors of all the species. Thus far, most previous studies focused on single fishways, while the studies of the combined types were limited to numerical simulations and few experiments were reported. In this work, we design a combined fishway composed of a notch weir, a rectangular central orifice, and a vertical slot, and experimentally study the turbulent structures of its flows. An acoustic Doppler velocimetry(ADV) is used to measure the threedimensional instantaneous flow velocities at all the gauge points in the combined fishway pool;and various flow characteristics are analyzed–time-averaged flow velocity, turbulence intensity, Reynolds stress, frequency-spectrum characteristics, correlation functions, and turbulence scales. The experimental results show the flow three-dimensionality of the combined fishway is more pronounced than that of a single type. Longitudinal flow velocity exhibits an obvious peak zone on the horizontal plane, and transverse and vertical velocities indicate a vortex occurring at cross sections. In the converging region between the vertical slot wall jet and orifice jet, the turbulence intensities of longitudinal, transverse and vertical velocities take large values and then are decreasing gradually after that. Reynolds stress shows a peak zone largely at the intersection of multiple jets. The dominant frequency of longitudinal fluctuation energy is the highest in central orifice passage, followed by notch weir and vertical slot. Longitudinal velocity fluctuations are correlated with time to a degree of the high-to-low order: notch weir, central orifice, and vertical slot;and their time periods increase along the main flow. The integral and micro scales show vortex structures are related to different flow regions in the combined fishway.
作者
董志勇
黄洲
余俊鹏
DONG Zhiyong;HUANG Zhou;YU Junpeng(College of Civil Engineering and Architecture,Zhejiang University of Technology,Hangzhou 310023)
出处
《水力发电学报》
EI
CSCD
北大核心
2020年第9期78-87,共10页
Journal of Hydroelectric Engineering
基金
国家自然科学基金项目(51779225)
关键词
水力学
组合式鱼道
流场矢量
三维流速
紊流结构
hydraulics
combined fishway
flow field vectors
three-dimensional velocity
turbulent structures
