Velocity Distribution and Energy Dissipation along Stepped Chutes Lined with Wedge-Shaped Concrete Blocks
Publication: Journal of Hydraulic Engineering
Volume 137, Issue 4
Abstract
Stepped channels lined with wedge-shaped concrete blocks may constitute a low-cost alternative to provide overtopping protection of embankment dams if the discharge capacity of existing spillways is not adequate or even to be used as the main spillway of newly built embankment dams. This paper addresses the velocity distribution and the energy dissipation, downstream of the inception point, on stepped chutes lined with wedge-shaped concrete blocks. An experimental setup was developed with two flumes designed with a relative scale of . Air concentration was measured with an optical probe in several cross sections of both flumes. The velocity profiles along chutes lined with wedge-shaped blocks with the upper face sloping downstream were analyzed. The measurements’ accuracy was checked by comparing discharges indicated by a facility flowmeter and obtained by the integration of velocity and air concentration profiles. The effect of the steps-slope in the energy dissipation is studied. Values of the Darcy-Weissbach friction factor are proposed for this type of chute lining, for transition flows, and for skimming flows.
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Acknowledgments
The writers want to acknowledge the financial support for facility construction and general collaboration of the UNSPECIFIEDPortuguese Institute of Water (INAG). The first writer wishes to thank the UNSPECIFIEDFoundation for Science and Technology for a Ph.D. grant. The writers also wish to acknowledge the support of the National Laboratory for Civil Engineering (LNEC) and the valuable collaboration of its experts during the development of the facility and the experimentation period.
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Information & Authors
Information
Published In
Journal of Hydraulic Engineering
Volume 137 • Issue 4 • April 2011
Pages: 423 - 431
Copyright
© 2011 American Society of Civil Engineers.
History
Received: Aug 5, 2009
Accepted: Sep 1, 2010
Published online: Sep 6, 2010
Published in print: Apr 1, 2011
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