Simplified Overshot Gate Constructed and Maintained by Irrigation Districts

Stringam, Blair L.; Gill, Tom

doi:10.1002/ird.1671

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…The first overshot gate patent was granted to R.A. Lang in 1890, the device did not incorporate much of today's irrigation requirements, as cited in Stringam, 2010;Stringam and Gill, 2012). The overshot gate has been the subject of few studies and published works.…”

Section: Introductionmentioning

confidence: 99%

The Overshot Gate as a Flow-Measuring Device

Qasim

2023

ARO

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The overshot gate is a commonly used adjustable overflow weir for regulating the upstream water level in open channels. The amount of gate movement is proportional to the water level change. However, to effectively manage the water flow, it is also important for operators to accurately measure the flow rate in the channel. This study examines an overshot gate installed at the end of a laboratory flume to estimate the flow rate under various free flow conditions. This study investigates different gate angles ranging from 9.6° to 90° to evaluate their impact on the flow properties and the discharge coefficient. The analysis of the results indicates that the maximum flow rate values can be achieved with gate inclinations from 15.5° to 47.2° with relatively lower head; the inclined alignment of the gate decreases the effective gate height which consequently increases the gate efficiency. The use of the overshot gate is advantageous over the normal gate when channel depth is limited and higher discharge is required at relatively lower head. In this study, at the highest gate inclinations, the water surface is significantly stable having the lowest values of the approach Froude number. In addition, the head to gate height ratio decreases with raising the gate due to the reduced vertical contraction of the channel. Finally, this paper proposes an empirical equation for estimating the discharge coefficient based on the gate inclination, which demonstrates good accuracy in the specified range.

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Section: Introductionmentioning

confidence: 99%

The Overshot Gate as a Flow-Measuring Device

Qasim

2023

ARO

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“…Therefore, researchers have studied more accurate predictions of discharge through gates by changing shape and form of gates such as the overshot gate (Stringam and Gill, 2012), weir gate (Salehi and Azimi, 2019), cylindrical edged sluice (Ferro et al ., 2019), and inclined sluice gate (Salmasi and Abraham, 2020). An example of a less‐known gate is the “LOPAC gate.” Aqua Systems 2000 Inc. (2013) introduced a rectangular prototype for the first time in the 1980s and provided relations for calculating the flowrate and the discharge coefficient.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of sudden canal contraction on the discharge coefficient and the energy dissipation coefficient of the elliptical LOPAC gate*

Kheybar

Sajjadi

Ahadyan

2021

Irrigation and Drainage

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Gates are usually made with a width smaller than the width of the canal to reduce construction and operation costs. In this study, the effect of a sudden contraction of the canal cross-section on the hydraulic performance of the elliptical LOPAC (EL) gate was investigated in vitro. To that end, 108 experiments were carried out at three different flow discharges (25, 35, and 45 L/s), four different gate widths or sudden canal contractions (b = 50, 60, 70, and 80 cm), three different submergence ratios (Y t /Y u = 0.7, 0.8, and 0.9), and three different gateclosing angles (15, 20, and 25). For this purpose, using the discharge coefficient and energy dissipation coefficient, distinct equations were obtained to estimate the discharge of the EL gate. By presenting an empirical relation, the discharge coefficient was estimated with a maximum error of ±9%. Experimental results showed that due to the sudden canal contraction, the discharge coefficient of the gate indicates a decrease of about 14%-73%. The energy drop coefficient for the EL gate was obtained based on experimental data. The energy dissipation coefficient was calculated to be 1.3 for the velocity head at the output of the EL gate, which estimated the discharge with a maximum error of ±11%. K E Y W O R D S discharge coefficient, elliptical LOPAC gate, energy dissipation coefficient Résumé Les vannes sont généralement fabriquées avec une largeur inférieure à la largeur du canal pour réduire les coûts de construction et d'exploitation. Dans cette étude, l'effet d'une contraction soudaine de la section transversale du canal sur les performances hydrauliques de la vanne elliptique LOPAC (EL) a été étudié in vitro. À cette fin, 108 expériences ont été menées à trois débits différents (25, 35 et 45 L/s), quatre largeurs de grille différentes ou des contractions brusques de canal (b = 50, 60, 70 et 80 cm), trois rapports de submersions différents (Y t /Y u = 0,7, 0,8 et 0,9) et trois angles d'ouverture de vanne différents (15, 20 et 25). Pour cela, en utilisant le coefficient de débit et le coefficient de dissipation d'énergie, des équations distinctes ont été obtenues * Effet de la contraction soudaine du canal sur le coefficient de débit et le coefficient de dissipation d'énergie de la vanne elliptique-LOPAC

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