Author(s): Shentang Dou; Yuanfegn Zhang
Linked Author(s):
Keywords: Hydraulics; Hyperconcentrated flow propagation; Characteristic theory; “Flood peak increase”
Abstract: Hyperconcentrated flow has always routed with unusual phenomena, Such as， “Flood peak increase”, for which, the available mechanism research is still not satisfactorily to explain. Based on the characteristic theory and the conservative equation that take the influence of sediment concentration into accounte on the process of flood routing, this paper analyzed the relation between hyperconcentrated flow propagation and the key factors, such as, longitudinal distribution of sediment concentration, erosion/sedimentation, the gravity and the resistance. Furtherly, combined with the analysis of the measured flood courses in the lower reach of the Yellow river, a one-dimensional model for simulating hyperconcentrated floods is proposed, in which continuity and momentum equations for turbid flows are adopted. Then the flood occurred in 2004 is used to verify the paper ’s conclusions. Simulated results showed that, the sediment concentration plays an important role in the process of flood routing, which influences the peak discharge, maximum sediment concentration, etc. After adopting the complete governing equations, simulated results agree better with the measured data. So, It is showed that the existence and uneven distribution of sediment extra the instability of flow routing. In addition, the density differences, sedimentation, and the decrease of resistance, are all the factors to cause the “Flood peak increase”.
Year: 2013