水科学进展2017，Vol.28Issue(3)：346-355,10.DOI:10.14042/j.cnki.32.1309.2017.03.004
明渠收缩过渡段流速分布及紊动特性试验
Experimental study on velocity profile and turbulencecharacteristics in open channel contractions
摘要
Abstract
Channel contractions are widely used in water diversion projects due to topographical and geological limitations.Short transitions would lead to water surface fluctuations and higher turbulence.To investigate the velocity and turbulence characteristics along transitions of different length, laboratory experiments were carried out using a two-dimensional electromagnetic current meter ACM2-RS.Results show that the longitudinal mean velocity increases along the centerline of the contraction while the longitudinal turbulence intensity decreases, which can be explained by vortex stretching mechanism and linear distortion theory.Influenced by secondary currents, the maximum velocity occurs below the surface.The stronger secondary circulation is, the lower the maximum velocity is located.Contractions of different length affect the velocity profiles and turbulence intensities downstream differently.Shorter contractions lead to higher magnitude of turbulence intensity downstream, while its vertical distribution remains the same in the region away from the bed, which decreases first and then increases with the vertical position going up.关键词
明渠收缩段/室内试验/流速分布/紊动强度/水面波动Key words
open channel contraction/laboratory experiment/velocity profile/turbulence intensity/water surface fluctuation分类
建筑与水利引用本文复制引用
吴永妍,陈永灿,刘昭伟..明渠收缩过渡段流速分布及紊动特性试验[J].水科学进展,2017,28(3):346-355,10.基金项目
"十二五"国家科技支撑计划资助项目(2015BAB07B09) （2015BAB07B09）
国家自然科学基金资助项目(51579130)The study is financially supported by the National key Technologies R&D Program of China during the 12th Five-year Plan Period (No.2015BAB07B09) and the National Natural Science Foundation of China(No.51579130). （51579130）
