Experimental Study About The Effect Of Vegetated Floodplains On Flow Internal Structure In Compound Channel

This paper is about physical modeling investigation on hydrodynamic behavior of compound channel with vegetated floodplains. Different materials are used to simulate different type of vegetations. By using high accuracy velocimeter ADV to measure velocity, the experiment studies the effect of the vegetations planting on the floodplains on flow internal structure.This paper summarized the achievements about flow characteristics of vegetated open channel roundly. The cross sections of compound channel are divided into 3 typical zones: main channel, floodplain and the area between main channel & floodplain, each of them was discussed respectively. The characteristic of longitudinal velocity and flow fields of transaction are investigated specially, which enrich the research findings of such subjects. The"second boundary"caused by the vegetation is also discussed with the help of the longitudinal velocity profile after planting the vegetation.The paper laid an emphasis on the study of floodplain with vegetation. A functional relation between longitudinal velocity inside vegetation and water depth is deduced by fitting the test data. The turbulence intensity and the coefficient of momentum transfer profile in this zone are also considered. This research also built a relationship between local head loss h j, drag coefficient of vegetation C d and the shear stress of bedτ0' in theory with considering"narrow effect"of vegetation.Finally, this paper takes an outlook about the construction of ecotypes watercourse.