Studying the effects of groin on Controlling the Sediments Entering the Intake Branching from a 180 Bend

ABSTRACT:Sediment control at lateral intakes is one of the most complicated problems in river engineering. Groin by set up a tip vortex and thereupon a helical flow in downstream, can reduce the movement of sediment into diversions. For guiding flow into diversion and reduce entering sediment to intake, a single groin in opposite side of intake is used. The main goals of the experiments were to evaluate the effect of groin’s length, distance from the intake and angle of attack on reducing the movement of sediment into diversion. Groins chocking percentage were, 10%, 15%, 20% and desistance from intake were 0, 20, 40 cm that angled at 70, 90 and 110 degree and ratio discharges were 0.3 ,0.35 , 0.4 , 0.45.This study investigates the effects of different variable parameters for installation of groin on 180 degree bend on performance of sediments entering the intake. Therefore, an arch-shaped flume with 180 ° angle, from which an intake channel located at 115° is branched with an angle of 45°, is used and 108 tests are performed at different conditions and different installation angles for groins.Using the tests results, the volume of sedimentsentering the intake, is measured in differentconditions. According to the results generallyas the angle increases from 70 to 90 degree, the volume of sediments entering the intake is reduced, so the efficiency is increased. But on the contrary, as the angle increases from 90 to 110 degrees, the volume of sediments entering the intake is increased, so the efficiency is reduced.It was concluded that, by using a groin in opposite side of intake, the volume of sediments entering the intake is decreased. By moving groin up to twice intake wide, sediment ingestion into diversion was reduced by average 25%. In addition, groin with angle 90 degree showed the best potential for reducing sediment movement into division in compare with groin associated with the 70 and 110 degree.