International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 7, Issue 1, pp: (71-82), Month: April 2019 - September 2019, Available at: www.researchpublish.com
Discharge formula for Thin Plated Rectangular Lab Fabricated Sharp Crested Weirs Shrikant A. Tekade1, Tejas P. Bhatkar2, Yuvraj A. Chavhan3 1
Assistant Professor, Department of Civil Engineering, Government College of Engineering, Nagpur, India 2
Geotech Engineer, Anandjiwala Technical Consultancy, Nagpur, India
3
Assistant Professor, Department of Civil Engineering, Shri Balaji Institute of Technology & Management, Betul (M.P.), India
Abstract: Sustainable development and efficient management of water is an increasingly complex challenge all over the globe. Sharp crested weir is used as a flow measuring device for open channel flow measurement. In rural India the measurement of flow is major challenge at field level because for flow measurement weir sections are made from standard procedure and also by using standard material prescribed in standard codes. In present experimental study sharp crested weir sections are made by mild steel and galvanized steel having a different crest height and width of weir opening are fabricated and tested in the laboratory. The present paper determines the feasibility of sharp crested weir of different material as a flow measurement device for open channel. Experimental data are generated to develop the relation between discharge vs. head over the weir and concluded that the coefficient of discharge value for each weir is same. Based on the experimental data a generalized weir equation for sharp crested weirs is proposed. Keywords: Open channel flow, Flow measurement, Coefficient of discharge, Rectangular weir.
I. INTRODUCTION Open channels are used for transportation of water for irrigation. Various advance techniques are used for open channel discharge measurement, to achieve the quantitative measurement effectively. But the initial as well as the maintenance cost is very high. To solve this problem the simplest and easier way can be the use of weir. A rectangular weir is a section having simple rectangular or other shape made by any material and inserted in the cross section of the channel for measuring the discharge. The form of head generated over the crest of weir is useful for measuring discharge. The weir can be classified into two types as sharp crested weirs and broad crested weirs. The nature of the crest segment for sharp crested weir is thin having thickness up to 2 mm, whereas for broad crested weir it is large. Francis (1883) carried out experimental work on long weirs having a crest length up to 10 feet. From experimental analysis a discharge equation for fully contracted rectangular weirs was proposed. and it was also mentioned that the values of discharge coefficient are constant for specific long weir section. Rehbock (1929) carried out experimentation on weir section and based on the experimental results investigator proposed a coefficient of discharge (Cd) empirical equation as,
h C d 0.611 0.08 p
(1)
h where h is head over the weir and p is crest height of p weir.The ranges for p was 0.10 m p 1.0 m and for h was 0.025m h 0.60 m respectively. Also it was documented that the Cd value depends on the ratio of
Page | 71 Research Publish Journals