Effect of Changing parametersof intake and main channel on the distance of dividing stream linefrom outer wall of bend

Direct dewatering of the river is used for irrigationand water supply and etc. Dewatering without diversion dam leads to a sediment settlement at the downstreamof intake in the main river. The distance of dividing stream line from the outer bank of the bend influences theamount ofsedimententering the intake.Anythingthat reduces the distance of dividingstream line from the outer wall of thebendat thebottomofthemain channel, willreduces sedimententering the intake. The geometricandhydraulicparameters of intake and main channelaffectthe distance of dividing stream line from the outer bank. Inthis study the effect ofparameterssuch aswidth and position of the intake, diversion angleandheightof the sill(Each one changes in four levels) on the distance of dividing stream line from the outer wall using the SSIIM numerical model is investigated. Also three angles(50, 110 and 170 degrees) and threedifferentFroude numbers (0.288, 0.305 and 0.322) forbendand three discharges ratio (10, 18 and 25 percent) for lateral intake areconsidered. Taguchi methodis usedin the design ofstudies. Theresults show that changing in width and position of the intake, diversion angleandheightof the sill have less influence on the distance of dividing stream line from the outer wall of the bend, but the variations of dividing stream line from the outer wall of the ben relative to the discharge ratio almost ascending and linear. Also, in a fixed-angle bend, changing the Froude number has a very small effect on the distance of dividing stream line.The Surface flow duct width is 0.9 to 1.25 times the width of the duct in the bed.