Discharge Coefficient Analysis for Triangular Sharp-Crested Weirs Using Low-Speed Photographic Technique
This article has a reply.
VIEW THE REPLYThis article has a reply.
VIEW THE REPLYThis article has a reply.
VIEW THE REPLYPublication: Journal of Irrigation and Drainage Engineering
Volume 140, Issue 3
Abstract
Triangular weirs are commonly used to measure discharge in open channel flow, representing an inexpensive, reliable methodology to monitor water allocation. In this work, a low-speed photographic technique was used to characterize the upper and lower nappe profiles of flow over fully aerated triangular weirs. A total of 112 experiments were performed covering a range of weir vertex angles (from 30° to 90°), crest elevations (8 or 10 cm), and discharges (). The experimental nappe profiles were mathematically modeled and combined with elements of free-vortex theory to derive a predictive equation for the weir discharge coefficient. Comparisons were established between measured , the proposed discharge coefficient equation, and discharge coefficient equations identified in the literature. The proposed equation predicts with a mean estimation error (MEE) of 0.001, a root-mean square error (RMSE) of 0.004, and an index of agreement (IA) of 0.984. In the experimental conditions of this study, this performance slightly improves that of the equation proposed by Greve in 1932, and showed the same absolute value of MEE but lower values of RMSE and IA.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
This research was funded by the Secretaría de Agricultura, Ganadería, Desarrollo Rural, Pesca y Alimentación of the Mexican Government (SAGARPA, Mexico) and the Secretaría del Campo of Zacatecas State Government (SECAMPO, Zacatecas). Thanks are also expressed to the Universidad Autónoma of Zacatecas, Mexico. Cruz Octavio Robles Rovelo received a scholarship from the Mexican Consejo Nacional de Ciencia y Tecnología (CONACYT).
References
Aydin, I., Altan-Sakarya, A. B., and Sisman, C. (2011). “Discharge formula for rectangular sharp-crested weirs.” Flow Meas. Instrum., 22(2), 144–151.
Bagheri, S., and Heidarpour, M. (2010). “Flow over rectangular sharp-crested weirs.” Irrigat. Sci., 28(2), 173–179.
Bautista-Capetillo, C. F., et al. (2009). “Comparing methodologies for the characterization of water drops emitted by an irrigation sprinkler.” Trans. Am. Soc. Agric. Biol. Eng., 52(5), 1493–1504.
Bos, M. G. (1989). Discharge measurement structures, Int. Institute for Land Reclamation and Improvement (ILRI), Wageningen, Netherlands.
Del Giudice, G., and Hager, W. H. (1999). “Sewer sideweir with throttling pipe.” J. Irrigat. Drain. Eng., 298–306.
El-Alfy, K. M. (2005). “Effect of vertical curvature of flow at weir crest on discharge coefficient.” 9th Int. Water Technology Conf., UNESCO Cairo Office and FAO Cairo Office, Cairo, Egypt, 249–262.
El-Hady, R. M. A. (2011). “2D-3D modeling of flow over sharp-crested weirs.” J. Appl. Sci. Res., 7(12), 2495–2505.
Emiroglu, M. E., Kaya, N., and Agaccioglu, H. (2010). “Discharge capacity of labyrinth side weir located on a straight channel.” J. Irrigat. Drain. Eng., 37–46.
Greve, F. W. (1932). “Flow of water through circular, parabolic, and triangular verticalnotch weirs.” Purdue Univ., Eng. Bull., 16(2), 84.
Novak, G., Kozelj, D., Steinman, F., and Bajcar, T. (2013). “Study of flow at side weir in narrow flume using visualization techniques.” Flow Meas. Instrum., 29, 45–51.
Salvador, R., Bautista-Capetillo, C., Burguete, J., Zapata, N., and Playán, E. (2009). “A photographic methodology for drop characterization in agricultural sprinklers.” Irrigat. Sci., 27(4), 307–317.
Shen, J. (1981). “Discharge characteristics of triangular-notch thin-plate weirs.” Studies of flow of water over weirs and dams, Geological Survey Water-Supply Paper 1617-B, United States Dept. of the Interior, Washington, DC.
Singh, N. P., Yada, S. M., and Singh, R. (2010). “Behavior of sharp crested weirs of various curvilinear shapes.” Proc., 13th Asian Congress of Fluid Mech., Bangladesh Society of Mechanical Engineers, Bangladesh, 17–21.
Sotelo, G., ed. (2009). Hidráulica general I: Fundamentos, LIMUSA, Mexico.
United States Bureau of Reclamation (USBR). (2001). Water measurement manual, Denver, Colorado.
Willmott, C. J. (1982). “Some comments on the evaluation of model performance.” Bull. Am. Meteorol. Soc., 63(11), 1309–1313.
Information & Authors
Information
Published In
Journal of Irrigation and Drainage Engineering
Volume 140 • Issue 3 • March 2014
Copyright
© 2013 American Society of Civil Engineers.
History
Received: Jul 19, 2013
Accepted: Nov 4, 2013
Published online: Dec 12, 2013
Published in print: Mar 1, 2014
Discussion open until: May 12, 2014
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.