The Effect of the Angle of T-shaped Spur Dike Position in the Bend on Flow Pattern Using Numerical Model (FLOW-3D)

In this research, flow pattern around T-shaped spur dike located in a 90 degree bend channel by using FLOW-3D software in the conditions of changing spur dike position along the bend (angles: 15, 30, 45, 60 and 75 degrees) with rigid bed was investigated. Accordingly, the numerical simulation results were first compared to experimental results under similar circumstances (45 angle position). The results of this comparison indicated that the numerical and experimental results enjoy rather appropriate correspondence. Therefore, after verification of numerical results, investigation of streamlines, length of flow separation and reattachment zones, and length of vortices under the influence of different positions of placing spur dike was conducted. The results obtained from numerical modeling indicated that at the layers near water surface and bed, for all angles of spur dike placement except position of 75 degrees, at downstream of spur dike a counterclockwise vortex has formed. Moreover, by changing the position of spur dike from the entrance of channel towards the exit of channel, at layer near bed, the maximum vortex length (as long as 4.7 times the spur dike length) for mode of spur dike placement in position of 15 degrees and the minimum vortex length (as long as 1.9 times the spur dike length) in position of 75 degrees have occurred.