Flow Patterns in Compound Channels with Vegetated Floodplains
Publication: Journal of Hydraulic Engineering
Volume 133, Issue 2
Abstract
Understanding the hydraulics of flow in a compound channel with vegetated floodplains is very important for determining the stage-discharge curve and for supporting the management of fluvial processes. In this paper, the flow patterns over different types of vegetation, such as tree, shrub, and grass, are described, based on an experimental study. For vegetation on the floodplain, the authors choose plastic grass, duck feathers, and plastic straws as model grass, shrubs, and trees, respectively. A 3D acoustic Doppler velocimeter was used to measure the local flow velocities for different types of vegetation on the floodplain, and the total discharge and flume slope were measured independently. In the cases of nonvegetated floodplains, all measured streamwise velocity distributions followed the logarithmic distribution, but for vegetated floodplains, they followed an S-shaped profile, exhibiting three zones. For all cases, the fluctuating velocity followed a normal distribution. The influence of different types of vegetation on the distributions of the secondary currents, turbulence intensities, and Reynolds shear stresses were also analyzed.
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Acknowledgments
The writers gratefully acknowledge the support of the 973 Program of China (No. 2003CB415202) and the National Natural Scientific Foundation of China (No. 50579040). The first author also wishes to acknowledge all the teachers and students in the River Engineering office of SKHL who offered much help during this research. Particular thanks are due to Professor Bing Shi, professor of civil engineering at the Ocean University of China, and his students, Mr. Yong Huang and Mr. Zhiyang Jiao, who participated in the experiments from the beginning to the end.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 133 • Issue 2 • February 2007
Pages: 148 - 159
Copyright
© 2007 ASCE.
History
Received: May 23, 2005
Accepted: Dec 16, 2005
Published online: Feb 1, 2007
Published in print: Feb 2007
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