Experimental Study of the Effect of Simultaneous Use of Skimming Wall on Velocity of Flow and Sediment Control in a Lateral Intake

Abstract In order to decrease the amount of sediment entering intakes, skimming wall could be used as control structure. Skimming wall changes the flow pattern and consequently changes the volume of sediment. In intakes, the average of the flow lines angles that enter the intake increases from the floor to the surface. The main propose of this research was to evaluate the effects of skimming wall and spur dike in controlling the sediment entrance and to find out the changes in velocity. The velocity components were determined in two dimensions- in the direction of the channel's length and perpendicular to flow in front of the span of the intake- and the angle of entry of the flow along the span of the intake. The velocity distribution and the method of entering and transporting of sediment to the intakes in different layers were investigated by using velocity angle of the entrance of flow to the intake and the longitudinal and transverse components of the velocity, Changes of velocity in front of the intake were compared in three layers. The results showed that the velocity angle of the surface layer was higher than that of  other layers, due to directing of flow through the spur, the existence of a separator wall structure and the effects on the middle and floor layers,. The spur dike caused longitudinal velocity near the bed layer increased 2.25 times, and the transverse velocity in the surface layer increased 1.33 times comparing to  when there is no spur dike.