水流移床力及河道运动力学的初步探讨  

A preliminary study on sediment-removing capacity and river motion dynamics

作　　者：王兆印 吴永胜[3] 刘芳[3] 

机构地区：[1]国际泥沙研究中心 [2]清华大学水利水电工程系,北京100084 [3]清华大学水利水电工程系

出　　处：《水利学报》2002年第3期6-11,共6页Journal of Hydraulic Engineering

基　　金：国家自然科学基金委资助项目 (5 9890 2 0 0 );水利部资助

摘　　要：本文首次提出了水流移床力和河道运动力学的概念 ,并建立了水流移床力与流量脉动强度的关系 .水流挟沙力是水流挟带泥沙通过河道的能力 ,而移床力则是水流改造河道的能力 .非恒定流输沙使水流具有移床力 ,因而造成河道运动 .研究发现 ,流量脉动强度愈大 ,移床力也愈大 .不同频率的脉动对移床力有不同的贡献 .在缺少河道实测运动资料的情况下 ,可以利用流量脉动能谱算出修正系数k推算实际水流移床力 .由移床力与流量脉动的关系可以推论 ,水流脉动强度愈大 ,河道愈不稳定 .利用水流移床力公式 ,可以计算和预测河道运动的速度和距离 .Sediment\|removing capacity is defined as the capacity of the flow to remove sediment from per unit length of a river section to other places per time.Differing from the well defined sediment carrying capacity,which is the feature of the mean flow and explains how much sediment load the flow can transport through the channel,the sediment removing capacity is the feature of unsteady,non equilibrium flow and represents the capability of the flow to change the channel shape and location.Measurement of the sediment removing capacity was performed at 12 cross sections of the wandering lower Yellow River.Analysis demonstrates that the removing capacity depends mainly on the fluctuation intensity of the flow discharge.The power spectrum of discharge is presented with Fourier transformation and it revealed the mechanism of high measurement frequency high sediment removing capacity.The movement of a river channel within the fluvial plain is defined as the river motion.The patterns of river motion are aggradation,degradation,widening,translation,rotation,wandering,bifurcation,and migration from one channel to another channel.The speed of the river motion is given as a function of the sediment removing capacity.

关 键 词：水流移床力 非恒定流输沙 河道动力学 流量脉动 能谱分析 

分 类 号：TV143[水利工程—水力学及河流动力学]