Discharge Coefficient of a Compound Weir with a Triangular underneath Gate for Different Geometric and Hydraulic Conditions
Received: 25 March 2024 | Revised: 17 April 2024 | Accepted: 7 December 2024 | Online: 2 February 2025
Corresponding author: Abdulrahman Seraj Almalki
Abstract
It is common practice in the field of irrigation systems to use composite hydraulic structures, which are constituted of two distinct parts. The initial component, represented by two rectangles, is responsible for the overflow regime, while the subsequent component, represented by a triangular gate, is responsible for the underflow regime. In order to measure, direct, and control the flow, both components are required. The present study investigates the flow through a combined two-rectangle weir with a below-triangular gate across the channel, which serves as a control structure. The weir's upper rectangle has a constant width, designated as b1 and measuring 20 cm, while the lower rectangle has a variable width, designated as b2 and comprising the values of 8 cm, 10 cm, and 12 cm. The depth of the lower rectangle, z, is also a variable with values of 6 cm, 9 cm, and 11 cm. The dimensions of the triangular gate are 15 cm in height and 0, 60, 90, or 120 degrees in vertex angle. The aforementioned dimensions were employed interchangeably as geometric conditions and the disparate water heads h2 as hydraulic conditions. Additionally, the compound weir devoid of a gate (θ = 0) was used for varying water heads. The results demonstrated that the dimensions of the weir and gate had an impact on the discharge that went through the two rectangular weirs and gates. In terms of discharge capacity, the combined structure was observed to be more effective than a classic weir, with the ability to convey a discharge that was two to ten times greater. An empirical formula was developed to predict the discharge coefficient, Cd, for the combined structure, based on the given geometric and hydraulic conditions. It should be noted that the results and analysis of this study were limited to the tested dataset.
Keywords:
compound weir, triangular gate, coefficient of discharge, combined structure, open channels, discharge measurementDownloads
References
F. Granata, F. Di Nunno, R. Gargano, and G. de Marinis, "Equivalent Discharge Coefficient of Side Weirs in Circular Channel—A Lazy Machine Learning Approach," Water, vol. 11, no. 11, Nov. 2019, Art. no. 2406.
S. Salehi and A. H. Azimi, "Discharge Characteristics of Weir-Orifice and Weir-Gate Structures," Journal of Irrigation and Drainage Engineering, vol. 145, no. 11, Nov. 2019, Art. no. 04019025.
M. G. Bos, Discharge measurement structures. Wageningen, Netherlands: International Institute for Land Reclamation and Improvement (ILRI), 1989.
S. Emami, J. Parsa, H. Emami, and A. Abbaspour, "An ISaDE algorithm combined with support vector regression for estimating discharge coefficient of W-planform weirs," Water Supply, vol. 21, no. 7, pp. 3459–3476, Apr. 2021.
A. B. Altan-Sakarya, M. A. Kokpinar, and A. Duru, "Numerical modelling of contracted sharp-crested weirs and combined weir and gate systems," Irrigation and Drainage, vol. 69, no. 4, pp. 854–864, 2020.
P. Ackers, W. R. White, and J. A. Perkins, Weirs and Flumes for Flow Measurement. New York, NY, USA: John Wiley & Sons, Ltd, 1978.
A. Alhamid, "Discharge equation for simultaneous flow over rectangular weirs and below inverted triangular weirs," Arab Gulf Journal of Scientific Research, vol. 14, no. 3, pp. 595–607, Jan. 1996.
N. Rajaratnam and K. Subramanya, "Flow Equation for the Sluice Gate," Journal of the Irrigation and Drainage Division, vol. 93, no. 3, pp. 167–186, Sep. 1967.
A. Zahiri, H. Md. Azamathulla, and S. Bagheri, "Discharge coefficient for compound sharp crested side weirs in subcritical flow conditions," Journal of Hydrology, vol. 480, pp. 162–166, Feb. 2013.
S. A. Sarhan and S. A. Jalil, "Analysis of Simulation Outputs for the Mutual Effect of Flow in Weir and Gate System," Journal of University of Babylon for Engineering Sciences, vol. 26, no. 6, pp. 48–59, Apr. 2018.
M. M. Muhammad and S. A. Abdullahi, "Experimental Study of Flow over Sharp Crested Rectangular-Triangular Weir Models," in Nigeria Engineering Conference, Zaria - Nigeria, Jan. 2014.
M. Piratheepan, N. E. F. Winston, and K. P. P. Pathirana, "Discharge Measurements in Open Channels using Compound Sharp-Crested Weirs," Engineer: Journal of the Institution of Engineers, Sri Lanka, vol. 40, no. 3, Jul. 2007.
H. Abd, A.-M. Hayawi, A. Abd, A. Yahia, and G. Abd, "Free Combined Flow Over a Triangular Weir and Under Rectangular Gate 1," Damascus University Journal, vol. 24, no. 1, pp. 9–22, 2008.
A.-A. M. Negm, A. m. Al-Brahim, and A. a. Alhamid, "Combined-free flow over weirs and below gates," Journal of Hydraulic Research, vol. 40, no. 3, pp. 359–365, May 2002.
A. A. Alhamid, A.-A. M. Negm, and A. M. Al-Brahim, "Discharge Equation for Proposed Self-cleaning Device," Journal of King Saud University - Engineering Sciences, vol. 9, no. 1, pp. 13–23, Jan. 1997.
S. I. Khassaf and M. Haheeb, "Experimental Investigation for flow through combined trapezoidal weir and rectangular gate," International Journal of Scientific & Engineering Research, vol. 5, no. 4, pp. 809–814, Apr. 2014.
A. A. G. Alniami, D. G. A. M. Hayawi, and H. a. M. Hayawi, "Coefficient Of Discharge For A Combined Hydraulic Measuring Device," Al-Rafidain Engineering Journal, vol. 17, no. 6, pp. 92–100, Dec. 2009.
J. M. Samani and M. Mazaheri, "Combined Flow over Weir and under Gate," Journal of Hydraulic Engineering, vol. 135, no. 3, pp. 224–227, Mar. 2009.
B. Balouchi and G. Rakhshandehroo, "Using Physical and Soft Computing Models to Evaluate Discharge Coefficient for Combined Weir–Gate Structures Under Free Flow Conditions," Iranian Journal of Science and Technology, Transactions of Civil Engineering, vol. 42, no. 4, pp. 427–438, Dec. 2018.
M. A. R. Eltoukhy, F. Abdelhaleem, T. H. Nasralla, and S. Shaban, "Effect of Compound Weir and below Circular Gate Geometric Characteristics on its Discharge Coefficient," International Journal of Scientific & Engineering Research, vol. 11, no. 10, pp. 1115–1130, Oct. 2020.
M. O. A. Alsaydalani, "Discharge Coefficient of a Two-Rectangle Compound Weir combined with a Semicircular Gate beneath it under Various Hydraulic and Geometric Conditions," Engineering, Technology & Applied Science Research, vol. 14, no. 1, pp. 12587–12594, Feb. 2024.
S. S. Ibrahim, R. A. Jafer, and B. M. A. S. Ali, "An Experimental Study of a Combined Oblique Cylindrical Weir and Gate Structure," Engineering, Technology & Applied Science Research, vol. 13, no. 2, pp. 10483–10488, Apr. 2023.
A. A. Mahessar, A. N. Laghari, S. Qureshi, I. A. Siming, A. L. Qureshi, and F. A. Shaikh, "Environmental Impact Assessment of the Tidal Link Failure and Sea Intrusion on Ramsar Site No. 1069," Engineering, Technology & Applied Science Research, vol. 9, no. 3, pp. 4148–4153, Jun. 2019.
C. E. Kindsvater and R. W. Carter, "Discharge Characteristics of Rectangular Thin-Plate Weirs," Journal of the Hydraulics Division, vol. 83, no. 6, pp. 1453–36, Dec. 1957.
M. L. Albertson, Y. B. Dai, R. A. Jensen, and H. Rouse, "Diffusion of Submerged Jets," Transactions of the American Society of Civil Engineers, vol. 115, no. 1, pp. 639–664, Jan. 1950.
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