Evaluation of the Flow Measurement Performance of Compound Sharp-Crested Over-Fall Weirs and Optimized Discharge Measurement in Data Scarce Areas

• Published in: Water resources 2022, Vol.49 (3), p.402-412
• Main Authors: Kassaye, Aklilu Alemayehu, Mohammed, Abdella Kemal, Angello, Zelalem Abera
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Coefficients; Constants; Discharge measurement; Earth and Environmental Science; Earth Sciences; Energy dissipation; Energy exchange; Flow measurement; Flumes; Hydraulic jump; Hydraulics; Hydrogeology; Hydrology/Water Resources; Hydrophysical Processes; Inflow; Measurement; Notches; Shape; Triangles; Turbulence; Waste Water Technology; Water Management; Water Pollution Control; Weirs
• ISSN: 0097-8078; 1608-344X
• DOI: 10.1134/S0097807822030034

The hydraulic relationships of flow through the weir of different common shapes were investigated in this study. The hydraulic performances of weirs were carried out experimentally, by using eight different types of weir models, and the effect of various shapes of the weir to specify different hydraulic parameters such as coefficient of discharge ( Cd ), weir geometric shape and size constants ( K ) and weir shape number ( n ), energy dissipation ratio ( E %) for selecting best flow measuring weir type. The experimental work was carried out on a tilted rectangular flume with 7.5 m long, 0.30 m wide and 0.45 m deep with a discharge range 0.50–20.95 L/s. The experimental results of this study showed that the dissipation energy corresponding to triangular notches is larger than the resulted from rectangular notches. For compound notches of rectangle and triangle, turbulence inflow increases as the angle of lower notch decreases. Thus, this type with an angle of (θ = 120 ο ) is the most efficient between the studied models, which gives the average Cd of 0.82, the value of K is equal to 0.75 and n values of 1.96, and the dissipation of flow energy ratio of (35.86%) for strong hydraulic jump. Finally, depending on a statistical basis, this study derived empirical relationships to estimate the coefficient of discharge with acceptable values of the coefficient of determination.