Comparative Study of Nonsymmetrical Trapezoidal and Rectangular Piano Key Weirs with Varying Key Width Ratios
Publication: Journal of Hydraulic Engineering
Volume 147, Issue 11
Abstract
Rectangular piano key weirs (RPKW) have been introduced as an innovative type of labyrinth weir with a smaller footprint and high hydraulic performance. To date, limited attention has been paid to PKWs with other planforms. In this study, experiments and numerical simulations were conducted to investigate and compare the discharge capacity of unsymmetrical trapezoidal piano key weirs (TPKW) and classical rectangular PKWs with varying inlet/outlet key width ratios. Results indicate that, even if all other parameters are held constant, the discharge capacity of a trapezoidal PKW can still be further improved by up to 10% through optimizing the key width ratio. Relative to RPKWs, TPKWs were proven to be more efficient, especially for high relative heads because of the larger outlet cross section, and less efficient for low relative heads due to the relative lack of total crest length. For the specific geometric configurations considered in this study, the optimal range of key width ratio for TPKW and RPKW is likely to be within 1.30 to 1.57 and 1.50 to 1.77, respectively. At the end of this study, a new PKW configuration is introduced, which combines the advantages of both geometries (rectangular and trapezoidal) and improves the overall weir efficiency up to 8%.
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Data Availability Statement
Some or all data, models, or code that support the findings of this study are available from the corresponding author upon reasonable request (all calculated discharge coefficients with corresponding values and all STL 3D-models are available upon reasonable request.
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Published In
Journal of Hydraulic Engineering
Volume 147 • Issue 11 • November 2021
Copyright
© 2021 American Society of Civil Engineers.
History
Received: Aug 27, 2020
Accepted: Jul 16, 2021
Published online: Sep 14, 2021
Published in print: Nov 1, 2021
Discussion open until: Feb 14, 2022
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