Mohammad Vaghefi

A spur dike is a structure that projects from a stream bank into the river channel and causes a redirection of ow away from the bank toward the tip of the spur dike. Construction of a spur dike against the ow causes significant changes in ow pattern in the channel. In this study, the ow pattern around a 25% submerged T-shaped spur dike in a 90  bend with rigid bed and various Froude numbers 0.2, 0.34, 0.45, and 0.6 was examined using FLOW-3D software. Numerical results were compared with experimental results and analyzed. The results indicated that in cross section around the spur dike, when Froude number increases, the formed vortexes decreased by 35%. Longitudinal velocity and lateral velocity increased twice as much as their former values. The highest amount of vertical velocity was observed between the wing of the spur dike and the external bend, and closer to the external bend, with an increase in Froude number, vertical velocity components variations decreased by 33%. Moreover, the results indicated that when the Froude number increases, the width of the separation zone increases, but the change in the length of the separation zone in dierent levels is negligible.