Experimental and numerical investigation of flow patterns in symmetrical spurs

Abstract

Spurs are hydraulic structures used to protect riverbanks from erosion and to concentrate the flow on the river axis. As the flow approach the spurs, discontinuous in the streamlines are occurred and vortices form before the spurs. In previous studies, spurs were generally placed on a one side of the open channel, and the vortices on the upstream and downstream were investigated. In this study, the changing flow velocities, and flow patterns on the upstream side of two spurs which are placed opposite each other on both side of the open channel were investigated. Spurs have same geometric parameters and placed with 90o the side wall angle. For 2 different discharge values (Q=17.66 lt/sn and Q=15.27 lt/sn), 3-Dimensional velocity measurements were made with ADV (Acoustic Doppler Velocimetry) at 20 different points on the upstream side of the spurs. With these obtained velocity profiles, flow patterns are investigated. Velocity values obtained from the numerical model give consistent velocity values with experiments and the maximum value of the margin of error between the models did not exceed 9%. In the experiments, the highest and lowest velocity values were measured as 3.2 cm/s and 88 cm/s, respectively. Unlike spurs placed at one side of the channel, no vortex was observed on the upstream side of the spurs in the experiments. © Computational Applied Mechanics .All rights reserved.