Discharge characteristics of lateral rectangular orifice intakes in open channel flow

Hydraulic intakes are frequently used in irrigation and drainage networks, hydropower, etc. for withdrawal of discharge. In this study, the coefficient of discharge for laterally placed single rectangular intakes under a uniform approach flow in an open channel was experimentally investigated. The variables influencing the coefficient of discharge of the intakes have been identified and used to develop an empirical relationship to predict the coefficient of discharge of the intakes. The proposed equation agreed with the observed data within ± 8% error. Analysis of data shows that the coefficient of discharge significantly influences by the intake width and intake height, approach Froude number, and intake Froude number. However, approach Froude number and intake aspect ratio were the most sensitive parameters affecting the coefficient of discharge. The coefficient of discharge was found to decrease as the aspect ratio of the intakes increases. The findings of this investigation would be advantageous for hydraulic engineers to design lateral rectangular intakes to withdrawal discharge from open channels.