Piano Key Weir Hydraulics and Labyrinth Weir Comparison
Publication: Journal of Irrigation and Drainage Engineering
Volume 139, Issue 3
Abstract
A piano key (PK) weir is a type of nonlinear (labyrinth-type) control structure with a relatively small spillway footprint. No standard PK weir design procedure is available, and the amount of published information on PK weirs is limited. PK weirs have a large number of geometric parameters that can affect head-discharge performance. A PK weir geometric design has, however, been recommended in the literature, along with a head-discharge relationship specific to that PK weir geometry. To develop a better understanding of the effects of PK weir geometry on discharge efficiency, nine laboratory-scale four-cycle PK weir configurations were tested (including the recommended design). The effects of the following PK weir geometry or modifications on weir performance were partially isolated: varying the inlet-to-outlet key ratio, raising the crest via a parapet wall, rounding the upstream apex walls, and varying the crest type. The appropriateness of the recommended head-discharge equation specific to the recommended design was evaluated, and the relative head-discharge efficiency of trapezoidal labyrinth and PK weirs with respect to footprint restrictions and crest length were compared.
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Acknowledgments
Research funding was provided by the State of Utah and the Utah Water Research Laboratory at Utah State University.
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Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 139 • Issue 3 • March 2013
Pages: 246 - 253
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jul 6, 2011
Accepted: Aug 8, 2012
Published online: Aug 20, 2012
Published in print: Mar 1, 2013
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