Experimental and numerical investigation of flow patterns in symmetrical spurs

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. By placing the spurs in an open channel, scours occur before and after the spurs due to changes in flow conditions and velocities. Determination of velocity distributions around the spur accurately is extremely important for spur design. For a sustainable and hydraulically efficient spur design, flow velocities, flow conditions, sediment characteristics and stream morphology around the spur should be well investigated. In this study, the changing flow velocities and flow patterns on the upstream side of two spurs with were investigated. Two spur which have same geometry placed in an open channel system at an angle of 90o with the side wall. 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. Velocity values obtained from the experiments were compared with the numerical models and gave consistent results with the numerical models. With these obtained velocity profiles, flow patterns are investigated.