摘要
为研究粗糙床面对明渠紊流流速结构的影响,设计6种圆柱型加糙床面,借助粒子图像测速仪(PIV)开展试验,对不同工况下的摩阻流速、时均流速等水流参数变化规律进行深入分析。结果表明:摩阻流速沿水流方向呈波齿状分布,表现出显著的分区特征,颗粒区摩阻流速整体小于粒间区,且其大小与颗粒直径、间距密切相关;时均流速随流量增大而增大,纵向分布呈现明显分区,粒间区较为平稳,颗粒区迅速减小,在颗粒顶部达到极大值,随后流动分离在粒间区,并在粒间区中心达到极小值,与典型粗糙元后尾流特征相符。时均流速随加糙颗粒间距减小而减小,随加糙体尺寸增大而减小;加糙体的影响有明显分区效应,对水流结构的扰动集中于近壁区,且流速出现垂向分布趋势,远离床面的主流区,流速分布趋于均匀横向分布。研究成果为揭示加糙床面水流运动规律提供了新的数据补充,可为河道整治、水利设施设计等工程应用提供参考。
To investigate the influence of bed roughness on flow velocity structure,six types of cylindrical rough beds were designed in this study.Experiments were conducted using Particle Image Velocimetry(PIV)to analyze in detail the variation patterns of flow parameters such as shear velocity and time-averaged velocity under different working conditions.The experimental results show that the shear velocity exhibits a serrated distribution along the flow direction,with distinct zonal characteristics.The shear velocity in granular regions is generally lower than that in inter-particle regions,and its magnitude is closely related to particle diameter and spacing.The time-averaged velocity increases with discharge and displays clear longitudinal zoning:it remains relatively stable in inter-particle regions but decreases rapidly in granular regions,reaching a maximum at the top of the particles.Flow separation occurs in inter-particle regions,where the velocity attains a minimum at the center,consistent with the wake characteristics behind typical roughness elements.The time-averaged velocity decreases as the spacing between roughness particles decreases and also diminishes with an increase in the size of roughness elements.The findings provide supplementary data for understanding flow dynamics over rough beds,offering references for engineering applications such as river regulation and hydraulic structure design.The influence of roughness elements exhibits notable zonal effects,with disturbances to the flow structure concentrated near the wall region.A vertical distribution trend in velocity is observed,while in the mainstream region away from the bed,the velocity distribution tends to become uniform horizontally.
作者
侯旭辉
张金楠
Hou Xuhui;Zhang Jinnan(School of Water Conservancy and Hydropower Engineering,Hebei University of Engineering,Handan 056038,China;Key Laboratory of Smart Water Conservancy in Hebei Province,Handan 056038,China)
出处
《吉林水利》
2026年第3期21-28,共8页
Jilin Water Resources
关键词
圆柱型加糙体
PIV试验
摩阻流速
时均流速
理论零点
阻力分区
Cylindrical roughening body
PIV
frictional flow velocity
mean flow velocity
flow velocity structure
