沙波迎流面流速及切应力垂线分布研究  

Vertical Distribution of Velocity and Shear Stress on the Stoss Side over Dunes

作　　者：丰青 肖千璐 张晓华[1,3] 郑艳爽 李彬[1,3] FENG Qing;XIAO Qianlu;ZHANG Xiaohua;ZHENG Yanshuang;LI Bin(Yellow River Institute of Hydraulic Research,Yellow River Conservancy Commission,Zhengzhou 450003,China;Key Laboratory of Lower Yellow River Channel and Estuary Regulation,Ministry of Water Resources,Zhengzhou 450003,China;Research Center for Ecological Protection and High-quality Development in the Yellow River Basin,Zhengzhou 450003,China)

机构地区：[1]黄河水利委员会黄河水利科学研究院,河南郑州450003 [2]水利部黄河下游河道与河口治理重点实验室,河南郑州450003 [3]黄河流域生态保护和高质量发展研究中心,河南郑州450003

出　　处：《工程科学与技术》2025年第2期93-103,共11页Advanced Engineering Sciences

基　　金：国家自然科学基金项目(52009047,51909100);水利部重大科技项目(SKS-20222061);中央级公益性科研院所基本科研业务费专项(HKY-JBYW-2023-24)。

摘　　要：沙波床面水流运动特性与平坦床面具有显著差异,现有沙波迎流面流速分布公式大多以水平流速作为研究对象,对沙波流速垂线分量空间分布变化对水平分量垂线分布的影响关注较少,未能完整描述沙波迎流面流速和切应力分布特征。基于经典沙波地形水槽实验观测数据,对沙波迎流面流速水平分量和垂线分量沿程分布进行统计分析;在此基础上提出流速偏移角的概念,用以描述沙波迎流角对流速水平分量和垂线分量分配的影响,研究了流速偏移角在沙波迎流面上的沿程分布规律;在沙波迎流面上建立子坐标系统,运用坐标旋转的方式建立了床面上方水体中标准坐标系统与近底子坐标系统转换关系,构建了沙波迎流面处流速矢量与水体主流流速矢量的数学关系,推导了考虑流速水平分量和流速垂线分量沿程调整规律的沙波迎流面流速和切应力垂向分布公式。结果表明:随着相对水深减小,流速偏移角向负值不断增大,在0.1倍相对水深处达到负最大值,而后开始减小,在临近迎流面处恢复为正值。流速偏移角自沙波迎流面近底处与水深呈指数函数关系,至水体上部时流速方向基本与主流方向一致。建立的沙波迎流面流速垂线分布公式计算值与实测数据基本一致,反映了沙波地形对其迎流面水流流速垂向分布和紊动扩散通量垂线分布空间变化的影响,进一步揭示了沙波床面水流运动特征和空间变化规律。Objective Dunes are shaped by the interaction between flow and sediment grains at the riverbed.The flow structures are influenced by bedforms and exhibit non-uniform characteristics due to changes in asymmetric features.Common formulas and predictors of flow structure are primarily based on the horizontal flow velocity over a flat bed and are described using length-averaged data of dunes.However,velocity over sand dunes continuously accelerates and decelerates along the stoss side,and the inherent relationship between the horizontal and vertical components is often neglected in velocity profile calculations.Experimental data and theoretical analysis are utilized to examine the variation characteristics of velocity and turbulent shear stress on the stoss side of dunes.Vertical distribution formulas for velocity and shear stress are derived,incorporating information on flow velocity's horizontal and vertical components.This study further reveals the effect of bedforms on flow characteristics and improves the calculation accuracy of velocity and turbulent shear stress over dunes.Methods The distributions of velocity and shear stress along the stoss side were quantitatively analyzed based on experimental data from flume studies with dunes.Statistical methods were employed to propose the concept of the flow velocity deviation angle.A sub-coordinate system near the riverbed was established based on dune geometry,and the relationship between the standard coordinate system and the sub-coordinate system was derived using coordinate rotation.Utilizing the vertical two-dimensional flow momentum equation and the Boussinesq hypothesis,theoretical derivations for the vertical distribution formulas of velocity and shear stress on the stoss side of dunes were developed.Experimental data from two published studies were utilized to validate the proposed formulas.Results and Discussions The variation characteristics of flow structure over dunes were influenced by both the stoss side angle and the horizontal distance along the stoss

关 键 词：沙波 流速垂线分布 流速偏移角 迎流面 紊动切应力 

分 类 号：TV122[水利工程—水文学及水资源]