Author(s): Dong Sop Rhee; Chang Wan Kim
Linked Author(s):
Keywords: Side weir; Discharge coefficients; Open channel flow
Abstract: Flood protection facilities like flood control channels or by-passes are very widely used to alleviate flood damage in urban and rural areas. These channels are usually connected to main channel via intake facility like side weirs. If they are connected through intake facility, the flow characteristics of the diversion sites are controlled by the hydraulic condition of the intake. Side weirs are essentially free over-flow weirs usually installed on the levees of along the sides of the main channel to divert water. Because these hydraulic structures are also extensively used in irrigation system or sewer system, the characteristics of side weirs have been studied already for the relatively narrow channels. However, the usual river width may be wider than channels in those systems. It might be supposed that the characteristics of the side weir may be changed for the relatively wide channels. Side weirs can be classified into sharp-crested and broad-crested side weirs. The discharge coefficient of sharp-crested side weir is usually function of the upstream Froude number Fr 1, the ratio of weir height to the upstream flow depth h/y 1, the ratio of weir length to the main channel width L/B and other influential parameters. Also, the discharge coefficient of broad-crested weir can be estimated based on those parameters, but, unlike sharp-crested side weirs, the weir width W has to be considered also because of its importance. The effects of the weir width W are considered by introducing another non dimensional influential parameter like (y 1 -h) /W (in which y 1 -h is overflow depth) (Ranga Raju, 1979). The main objective of this study is investigating experimentally the effects of upstream Froude number, weir height, weir length, weir width and main channel width on the discharge coefficients of broad-crested side weirs under subcritical flow conditions in a relatively wide rectangular open channel.
Year: 2010