Experimental investigation on local shear stress and turbulence intensities over a rough non-uniform bed with and without sediment using 2D particle image velocimetry
Experimental investigation on local shear stress and turbulence intensities over a rough non-uniform bed with and without sediment using 2D particle image velocimetry作者机构：CD-Laboratory of Sediment Research and ManagementInstitute of Water ManagementHydrology and Hydraulic EngineeringDepartment Water-Atmosphere-EnvironmentUniversity of Natural Resources and Life Sciences
出 版 物：《International Journal of Sediment Research》 (国际泥沙研究(英文版))
年 卷 期：2020年第35卷第2期
页 面：193-202页
核心收录：
学科分类：08[工学] 081502[工学-水力学及河流动力学] 0815[工学-水利工程]
基 金：The financial support by the Federal Ministry of Economy Family and Youth and the National Foundation of Research Technology and Development of Austria
主 题：Turbulence measurement Local bed shear stress Sediment transport and flow interaction Hydraulic flume experiment Particle image velocimetry
摘 要：The current work focuses on locally resolving velocities,turbulence,and shear stresses over a rough bed with locally non-uniform character.A nonporous subsurface layer and fixed interfacial sublayer of gravel and sand were water-worked to a nature-like bed form and additionally sealed in a hydraulic ***-dimensional Particle Image Velocimetry(2 D-PIV) was applied in the vertical plane of the experimental flume *** with clear water and weak sediment transport were done under slightly supercritical flow to ensure sediment transport conditions without formation of considerable sediment deposits or *** study design included analyzing the double-averaged flow parameters of the entire measurement domain and investigating the flow development at 14 consecutive vertical *** geometrical variabilities as well the presence of sediment were mainly reflected in the vertical velocity *** the vertical velocity decreased over the entire depth in presence of sediment transport,the streamwise velocity profile was reduced only within the interfacial *** the region with decelerating flow conditions,however,the streamwise velocity profile systematically increased along the entire depth *** increase in the main velocity(reduction of flow resistance)correlated with a decrease of the turbulent shear and main normal ***,effects of rough bed smoothening and drag force reduction were experimentally documented within the interfacial sublayer due to mobile ***,the current study leads to the conclusion that in nonuniform flows the maximum Reynolds stress values are a better predictor for the bed shear stress than the linearly extrapolated Reynolds stress *** is an important finding because,in natural flows,uniform conditions are rare.
同方期刊数据库