Investigation of Flow Pattern Change at Lateral Intake due to Inclination of Channel Bank

Lateral intake is a hydraulic structure which is used for diversion of some portion of water from a river. In this paper because of the importance of sediment entry to the intake, flow patterns and the most important factors affecting the sediment entry has been studied. Stream tube is the most important parameter in flow and sediment diversion. Stream tube is a part of main channel that divert sediment and flow to intake. Stream tube dimensions at different depths have a significant impact on sediment diversion into the intake. Most of previous studies have been conducted on rectangular canal. In this study experimental tests are conducted in trapezoidal canal with four different bank slopes. Three components of flow velocity at three different flow depths was measured using ADV velocity meter. Using data the streamline were plotted and stream tube dimension were determined. The results show that the stream tube dimensions for trapezoidal canal is different than it is in rectangular canal for the same discharge ratio. It was found that the bottom stream tube width is less than it is in rectangular canal. Since sediment concentration at lower layer is high, for the same flow discharge ratio sediment entry to the intake is reduced when the canal banks are inclined.