Experimental study of discharge coefficient of a Trapezoidal Piano Key Side Weir

Document Type : Research Article


1 Civil enginiering,College Engineiring, tehran University, Tehran,Iran.

2 River and coastal Engineering ,Soil Conservation and Watershed Management Research Institute, Tehran,Iran

3 Professre of university Tehran


Spillway is a hydraulic structure that is used to cross overwaters and floods from upstream to downstream of dams. Side weirs are a variety of hydraulic structures that are designed for various purposes in water transfer systems. The side weirs is constructed with an elevation less than the wall height of the canal, and when the water level rises, spillway will regulate the flow rate and control the water level in the main channel. This research done, in a laboratory review, a canal with a length of 10 meters 0.6m wide, 0.6 height and 16 types of piston cluster type A trapezoidal piano key side weir with different tripods 10, 15 and 20 cm. The above-mentioned overflows are under consideration. The results show that the overflow with a base of 15 cm in both cases has a maximum flow rate coefficient in the ratio of the0.2> H/P> 0.4and has a fluctuation ratio of 0.5


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