Experimental Study of Discharge with Sharp-Crested Weirs

Authors: E. Keramaris, V. Kanakoudis

Abstract:

In this study the water flow in an open channel over a sharp-crested weir is investigated experimentally. For this reason a series of laboratory experiments were performed in an open channel with a sharp-crested weir. The maximum head expected over the weir, the total upstream water height and the downstream water height of the impact in the constant bed of the open channel were measured. The discharge was measured using a tank put right after the open channel. In addition, the discharge and the upstream velocity were also calculated using already known equations. The main finding is that the relative error percentage for the majority of the experimental measurements is ± 4%, meaning that the calculation of the discharge with a sharp-crested weir gives very good results compared to the numerical results from known equations.

Keywords: Sharp-crested weir, weir height, flow measurement, open channel flow.

Digital Object Identifier (DOI): doi.org/10.6084/m9.figshare.12489560

References:

[1] Moore, W.L. Energy losses at the base of a free overall, Trans. of ASCE, 108, 1343-1387, 1943.
[2] Kandaswamy, P.K., Rouse, H. Characteristics of flow over terminal weirs and sills, Proc. ASCE, J. Hydraulics, 83(4), 1-13, 1957.
[3] Vickery, L. The rise of water level behind the nappe of a rectangular weir, J. Mech. Eng. Sci., 10(1), 81-89, 1968.
[4] Rajaratnam, N., Muralidhar, D. Pressure and velocity distribution for sharp-crested weirs, J. Hydr. Res., 9(2), 241-248, 1971.
[5] Fritz, H.M., Hager, H.W. Hydraulics of embankment weirs. J. of Hyd. Eng., ASCE, 124(9), 963-971, 1998.
[6] Aydin, I., Ger A.M., Hincal, O. Measurement of small discharges in open channels by slit weir. J Hyd. Eng, ASCE, 128(2), 234–237, 2002.
[7] Rady, R. 2D-3D Modeling of flow over sharp-crested weirs, J. of App. Sci. Res., 7(12), 2495-2505, 2011.
[8] Gharahjeh, S., Aydin, I., Sakarya, A. Discharge formula for sharp-crested rectangular weirs, 10th International Congress on Advances in Civil Engineering, Ankara, Turkey, October, 2012.
[9] Ramakrishna, B., Vaheed, S., Adilakshmi, P.S.V. Flow characteristics of sharp crested weirs, Int. J. of Adv. Res. in Sci,, Eng. and Tech., 5(12), 7650-7654, 2018.
[10] Gong, J., Dend, J., Wei, W. Discharge coefficient of a round crested-weir, Water, 11, 1206, 1-9, 2019.
[11] U.S. Dept. of the Interior, Bureau of Reclamation, 2001 revised, 1997 third edition, Water Measurement Manual, 2001.
[12] https://www.lmnoeng.com/Weirs/vweir.php.
[13] Dey, S., Sarkar, A., The impact characteristics analysis of free over-fall flow on downstream channel bed, J. of the Chin. Inst. of Eng., 34(3), 403-413, 2011.
[14] Chen, J.Y., Huang, H.S., Hong, Y.M., Liu, S.I., Kandaswamy, P.K., Rouse, H. Characteristics of flow over terminal weirs and sills, Proc.