非恒定流驱动下床面形态变化特征  

Study on the characteristics of bed forms developed under unsteady flows

作　　者：王乐[1] Alan J S Cuthbertson 张尚弘[1] 王永强[3] WANG Le;Alan J S Cuthbertson;ZHANG Shanghong;WANG Yongqiang(School of Water Resources and Hydropower Engineering,North China Electric Power University,Beijing 102206,China;School of Science and Engineering,University of Dundee,Dundee DD14HN,UK;Department for the Integrated Use of Water Resources,Yangtze River Scientific Research Institute,Wuhan 430010,China)

机构地区：[1]华北电力大学水利与水电工程学院,北京102206 [2]School of Science and Engineering,University of Dundee,Dundee DD14HN,UK [3]长江科学院水资源综合利用研究所,湖北武汉430010

出　　处：《水科学进展》2021年第5期751-758,共8页Advances in Water Science

基　　金：国家自然科学基金资助项目(52009041;52061135104)。

摘　　要：为深入认识非恒定流驱动下床面形态的演变规律及尺度变化趋势,采用水泵控制系统生成了一系列历时与洪峰流量不同的洪水过程来冲刷由粗沙组成的实验动床(中值粒径d 50=1.95 mm),研究中运用非恒定流的形态、非恒定性及水流做功参数来量化洪水过程;统计分析河床高程数据得到床面形态的波长、波高及陡度。实验结果表明:在不同尺度的非恒定流洪水作用下,实验动床表面分别形成了沙垄、交错边滩以及介于两者之间的过渡型床面形态;洪水的非恒定性对床面形态尺度的影响最大,其次是水流做功参数,而非恒定流的形态影响较为微弱;在此基础上构建了用于描述非恒定流驱动条件与床面形态尺度响应的定量关系。The main objective of this study is to investigate the morphological response and variability in the wavelength,height,steepness of bed forms developed over a quasi-uniform,coarse-sand bed under unsteady flows,with zero sediment feed condition specified at the upstream boundary.A series of smooth,bell-shaped hydrographs are generated within a titling flume,each defined parametrically by their shape(η),unsteadiness(ΓHG)and total water work(W k).By contrast,the bed forms generated in the sediment bed are quantified through their wavelength(λ),height(D)and steepness(ψ).Experimental results indicate that different categories of bed forms,such as dunes,alternate bars,or transitional structures,developed on the bed surface over the hydrograph duration.A close examination of relative importance of three hydrograph s parameters(i.e.η,ΓHG and W k)on bed-form dimensional descriptors(i.e.λ,D,ψ)reveals that the flow unsteadiness and total water work appear to be the primary and second-order control on bed-form category developed and their overall magnitude,whereas the hydrograph shape(η)appears to have a minimal impact.Based on this knowledge,a constitutive model to describe the effect of unsteady flow hydrographs on the bed-form categories and magnitude is developed from the results in the present study.

关 键 词：非恒定流 洪水 床面形态 

分 类 号：TV122[水利工程—水文学及水资源]