Effect of Section Constriction Due to T-shaped Spur Dike in a Bend on Flow Pattern Using FLOW-3D Software

Spur dikes are one of the many kinds of hydraulic structures, and they are employed in stabilizing rivers’ outer walls and redirecting the flow. Considering the importance of understanding flow pattern around the spur dikes, the present work firstly simulated the flow pattern around a T-shaped spur dike located in a 90 degree bend channel. The rigid-bed channel’s curvature radius and radius to width ratio were respectively 2.4 and 4. FLOW-3D was used in order to simulate the flow pattern, and the effect of section constriction on the flow pattern was studied afterwards. VOF was used for distinguishing the water surface profile from the open surface model, and RNG k-ɛturbulence model was employed to model the turbulent flow around the spur dike. The piece of research indicated an acceptable correspondence between numerical and experimental results. The results obtained through various simulations per 10, 20 and 25% constrictions of the section indicated that increase in section constriction would increase the water surface fluctuations, and the maximum height upstream and the minimum height downstream were observed in the case of the large spur dike. In addition, the vortices appear over a longer area of the bend, downstream the spur dike.