Experimental evaluation of discharge coefficient and performance of sloped and Non-sloped rectangular and trapezoidal piano key weirs

Shokri, Morteza; Gholami, Ali

doi:10.22126/arww.2026.11468.1350

Document Type : Research Paper

Authors

Department of Civil Engineering, Faculty of Engineering, Bu-Ali Sina University, Hamedan, Iran.

https://doi.org/10.22126/arww.2026.11468.1350

Abstract

The discharge of sloped piano key weirs (PKWs) is proportionate to the upstream head, which allows for improving hydraulic performance under various conditions. This study experimentally investigates the discharge coefficient and hydraulic performance of sloped and non-sloped PKWs with rectangular and trapezoidal sections. The goal was to evaluate the effects of the crest slope of sidewalls on the discharge coefficient and performance of a PKW. Tests were performed in an experimental flume with a length of 15 m and a height of 60 cm. Rectangular and trapezoidal type-A PKWs with 0° and 15° inclinations were studied. This study also incorporated the effect of the Weber number on the discharge coefficient of PKWs by evaluating hydraulic data. It was found that sloped rectangular and trapezoidal PKWs, where over 75% of the crest length contributed to the discharge, had larger discharge coefficients than their non-sloped counterparts. Moreover, in light of their larger effective length, sloped trapezoidal PKWs had a 13% greater discharge coefficient than sloped rectangular PKWs on average. This suggests that sloped PKWs could improve flood management and water storage efficiency.

Keywords

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Journal of Applied Research in Water and Wastewater

Experimental evaluation of discharge coefficient and performance of sloped and Non-sloped rectangular and trapezoidal piano key weirs

References

References

Articles in Press, Accepted Manuscript
Available Online from 17 February 2026

Experimental evaluation of discharge coefficient and performance of sloped and Non-sloped rectangular and trapezoidal piano key weirs

References

References

Articles in Press, Accepted Manuscript Available Online from 17 February 2026

Articles in Press, Accepted Manuscript
Available Online from 17 February 2026