Rectangular Lateral Orifices in Open Channels

The theory of lateral flow through a two‐dimensional channel outlet is used to derive an expression for the flow through a rectangular lateral orifice discharging from a rectangular channel. The orifice discharge coefficient is expressed as a function of a parameter relating the length of the orifice and the width of the main channel and a parameter denoting the ratio of the mean velocity in the main channel to the resultant velocity of the jet through the orifice. Experimental results are provided to validate the proposed expressions for the orifice discharge coefficient.