Modeling Study of Free Overfall in a Rectangular Channel with Strip Roughness
Publication: Journal of Hydraulic Engineering
Volume 134, Issue 5
Abstract
Results from combined laboratory experimental and turbulent numerical modeling studies are presented to investigate the effects of bed roughness (discrete square strips) and slope on the flow over a free overfall in a rectangular channel. A broad range of model parameters such as the bed roughness, channel slope, and incoming upstream Froude number is investigated. The water surface profiles upstream of the brink of the channel, the velocity fields in cavity between two strips, and end depth (water depth at the brink of the channel) are simulated, measured, and discussed for various input conditions. The results show that for a given dimension of bed roughness the relative spacing of roughness (defined as the ratio of the center to center distance to the height of the strip) has a significant effect on the flow. The computational results are in good agreement with the experimental measurements.
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Acknowledgments
The writers are grateful for the support of this work by the National Natural Science Foundation of China (Grant No. NNSFC50579025), the National Basic Research (973) Program of China (Grant No. UNSPECIFIED2005CB724202), and Carnegie Trust for the Universities of Scotland. The discussions with Professor V. Nikora, Dr. L Campbell and Dr. Pokrajac are acknowledged. The constructive comments and suggestions made by three anonymous reviewers, the associate editor, and editor greatly improved the quality of the technical node.
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© 2008 ASCE.
History
Received: May 22, 2006
Accepted: Apr 9, 2007
Published online: May 1, 2008
Published in print: May 2008
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