An Experimental Study of a Combined Oblique Cylindrical Weir and Gate Structure

Abstract

In the present study, the effects of different oblique angles and diameters on the cylindrical weir and below a gate as a combined device have been studied experimentally. For this purpose, sixteen models of combined cylindrical weir-gate structures have been tested in a laboratory flume. These models had four different oblique angles α (300, 450, 600, and 900). For each angle, the diameter of cylindrical weir-gate changed four times (4, 7.3, 9, and 11cm). The results of all models indicate that the theoretical discharge (Qth) is inversely proportional to the ratio of diameter to height (D/h) and length to height (L/h). As the diameter increases and oblique angles decrease, the actual discharge (Qact) increases. A general expression was established linking Qth/g1/2h5/2 and the discharge coefficient Cd with D/h, L/h, and alfa. The discharge coefficient ranged from 0.55 to 0.99 for various oblique angles and decreased as the angle increased. A strong correlation was observed between the estimated and the calculated values.

Discharge Coefficient of a Two-Rectangle Compound Weir combined with a Semicircular Gate beneath it under Various Hydraulic and Geometric Conditions

“…However, this potential issue can be avoided by combining gates with weirs. Conversely, when weirs are used exclusively, sedimentation problems may arise, but these can also be addressed by combining weirs and gates [1][2][3][4]. The hydraulic behavior of these combined weir and gate structures differs from that of individual weirs or gates.…”