Experimental Investigation of Discharge Coefficient in Tainter (Radial) Gate with Sill in Free Flow Conditions

Document Type : Research Article


Department of Science and Water Engineering, Agriculture faculty, University of Tabriz, Tabriz, Iran


In the present study, the effect of sill on the discharge coefficient (Cd) of radial gates in a free flow condition has been investigated. Variable geometric parameters of these sills are length, upstream slope, downstream slope and sill height. In addition, the effect of sill location on Cd was investigated so that in case 1, with an open gate, the sill was located in front of the gate. In case 2, the sill is located under the gate and not in front of it. In total, 43 physical models of different shapes of sills and different sizes of sills were used. The results showed that when the radial gate is open and sills are in front of the gates (case 1), the sill operates as a barrier and reduces Cd. But in case 2, the semicircle shape has a better performance and increases Cd by about 30%. Also, the rectangular and trapezoidal sills always increase Cd. In these sills, increases in Cd depend on the sill length to its height (L/Z). Small values of L/Z increase the discharge coefficient up to 25%. Finally, for circular and semicircular sill shapes, two regression equations were presented which can be used by designers.


Main Subjects

[1] M.K. Beyrami, Water conveyance structure, Isfahan University Press, 2006.
[2] A. Negm, A. Alhamid, A. Elsaid, Submerged flow below sluice gate with sill, Egyptian society of engineers, 26(4) (1998) 31-36.
[3] A. Sarhan, Analysis of submerged flow under a gate with prismatic sill, ARPN Journal of Engineering and Applied Sciences, 8(10) (2013) 849-856.
[4] Y. Saad, Effect of circular-crested sill shapes under sluice gate on supercritical free flow characteristics, Ain Shams University, Engineering Bulletin, 42(4) (2007) 161-173.
[5] A. El-Saiad, E. Abdel-Hafiz, M. Hammad, Effect of sill under gate on the discharge coefficient, Journal of Egyptian Society of Engineers, 30(2) (1991) 13-16.
[6] S. Neveen, Flow Under a Submerged Gate With a Circular- Crested Sill, Nile Basin Water Science & Engineering Journal, 4(2) (2011) 1-9.
[7] Y. Aminpour, M. Yasi, J. Farhoodi, A. Khalili Shayan, Experimental and Field Investigation of the Use of Radial gates as Flow Measurement Structures at Free and Submmerged Flow Conditions, Journal of Water and Soil, 28(4) (2014) 596-607.
[8] E.M. Shahrokhnia, M. Javan, Discharge coefficient estimation for Arched gates, Journal of Hydraulic Engineering, 1(1) (2005) 1-11.
[9] M. Negm, M. Abdelaal, M. Salem, Characteristics of submerged flow below gate with sill in non-prismatic channel, in: 6th International Water Technology Conference, Alexandria, Egypt, 2001.
[10] F. Fahmy Salah, Hydraulics of submerged radial gates with a sill, ISH Journal of Hydraulic Engineering, (2017).
[11] M. Aydin, A. Emre, Numerical modelling of sluice gates with different sill types under submerged flow conditionsJournal of Science and Technology, 7(1) (2017) 1-6.
[12] J. Shaker, Submerged Flow Analysis below a Vertical Gate with Stepped Sill, Caspian Journal of Applied Sciences Research, 3(5) (2014) 41-52.
[13] M. Salama, Flow below sluice gate with sill, Journal of Egyptian Society of Engineers, 26(4) (1987) 31-36.
[14] M. EL-Ganainy, M. Abourehim, F. Fitiany, Radial gates with gate sill for irrigation structure, Alexandria engineering journal, 35(6) (1996) 303-309.
[15] US ARMY CORPS OF ENGINEERING, Washington, D.C., United States, 2011.