A New Approach to Analyze the Flow over Sharp Crested Curved Plan form Weirs
S. Kumar1, Z. Ahmad2, T. Mansoor3, S. K. Himanshu4
1Dr. Sanjeev Kumar, Associate Professor, Department of Civil Engg., GEU, Dehradun (Uttarakhand), India.
2Dr. Z. Ahmad, Professor, Department of Civil Engg., IITR, Roorkee (Uttarakhand), India.
3Dr. Talib Mansoor, Associate Professor, Department of Civil Engg., ZHCET, AMU, Aligarh (U.P), India.
4Mr. Sushil Kumar Himanshu, Associate Professor, Department of Civil Engg., GEU, Dehradun (Uttarakhand), India.
Manuscript received on 21 March 2013 | Revised Manuscript received on 28 March 2013 | Manuscript published on 30 March 2013 | PP: 24-28 | Volume-2 Issue-1, March 2013 | Retrieval Number: A0466032113/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: Weirs have widely been used for the flow measurement, flow diversion and its control in the open channels. Generally they are used as normal weirs of various shapes like rectangular, triangular, trapezoidal, etc. pose problems of submergence upstream of the weir due to large afflux required to pass the discharge downstream. Several weirs of modified plan form like oblique weirs, diagonal weirs, Duckwill weirs, Labyrinth weirs etc. have successfully been used to control the afflux and to enhance their discharging capacity with minimum head over the weirs. Labyrinth weirs are folded in the plan view (i.e. the weir crest is not straight in plan form) to provide a longer crest length compared to a normal weir having the same lateral space to increase the discharge for a given operating head. For large reservoirs, the labyrinth weir is used as the overflow structure. It allows the overflow sill to be raised for the same maximum level of the water and flood, and thus, increase the storage capacity of the reservoir. This paper contains the results of experimental study carried out to analyse the flow characteristics of a sharp-crested curved plan-form weirs under free flow conditions in a rectangular channel with weir height around 0.10 m and vertex angles ranging from 0 0 (i.e. normal weir) to 1200 . The equations for the discharge coefficient of curved weirs have been proposed. The results show that there is a gain of about 50% in discharge over a curved weir with vertex angle of 120 0 as compared to a normal weir. Finally, equations for discharge coefficient for all tested curved weirs in a free flow situation have been proposed.
Keywords: Sharp Crested Weir, Curved Plan-Form, Flow Measurement, Coefficient Of Discharge, Open Channel.
Scope of the Article: Expert Approaches