基于特征分析的多沙河流洪峰流量增值机理研究  

Study on the mechanism of flood peak discharge increasing in sediment-laden rivers based on characteristic analysis

作　　者：丁赟[1] 钟德钰[1] 张红武[1] 

机构地区：[1]清华大学水沙科学与水利水电工程国家重点实验室,北京100084

出　　处：《水力发电学报》2010年第5期202-208,225,共8页Journal of Hydroelectric Engineering

基　　金：国家自然科学基金资助项目(50979041)

摘　　要：黄河下游等多沙河流通过高含沙洪水时常出现洪峰流量增值这一异常现象。从描述多沙河流水沙运动的耦合数学模型出发,基于模型所构成的双曲系统的特征理论,分析了多沙河流洪峰流量沿程增值机理。从所获得的耦合模型的特征关系上看,当河床存在显著变形时会对浅水波的传播特性产生较大影响。河床冲刷时水流中扰动传播速度变慢,而河床淤积时水流中扰动传播变快。因此,多沙河流高含沙洪水过程中河床出现的"涨冲落淤"现象使得后期落水阶段河床变形对水流运动产生的扰动较前期涨峰时更快,是产生洪峰增值现象的原因之一。The phenomenon of flood peak discharge increasing frequently occurs in the lower reach of Yellow River.This paper studies the mechanism of this unusual phenomenon by using a coupled mathematical model and the characteristic theory of hyperbolic system.In perspective of the characteristic relationship of the coupled system,if the bed deformation is large it plays a significant role in the propagation of shallow water waves.In general,the flow disturbances travel at a lower speed in a river channel undergoing bed scour,but they travel faster in a river undergoing deposition.During a flooding event in a sediment-laden river,bed scouring occurs at the earlier discharge increasing stage,while deposition occurs at the later stage of discharge decreasing.Thus,the waves traveling faster at the later stage will eventually catch up the ones traveling slower,and the result must be an increase in the flood peak discharge.

关 键 词：泥沙动力学 多沙河流 洪峰增值 双曲理论 特征 河床变形 

分 类 号：TV147[水利工程—水力学及河流动力学]