Flow Pattern Around Attractive, Vertical, and Repelling T-Shaped Spur Dikes in a Mild Bend Using CFD Modeling

Abstract

This piece of research presents flow pattern around a T-shaped spur dike in repelling, attractive, and vertical positions in a 90° mild. To this aim, SSIIM CFD software, one of the most powerful software applications in hydraulic engineering field, was employed. In this research, Navier–Stokes equations and k–e turbulent model were used for solving the flow field. The numerical results were verified using the experimental data. The comparison between the results of numerical simulation and experimental data collected by ADV velocimeter indicated a desirable agreement. The numerical results showed that the dimensions of the vortex at the downstream side of the spur dike reduced by increasing the angle of the spur dike. Moreover, the secondary flow strength value was the maximum for attractive and then repelling modes. Variation of the secondary flow strength for repelling, attractive, and vertical modes ranged from zero to 45, 35, and 25% respectively. Although the range of the secondary flow values in vertical mode for both numerical and experimental models was identical and about 0–25%, less than a 5% error between these two models demonstrated that the amount had been reasonable. By determination of flow separation zones, it was observed that, for all the three modes, the separation zone length increased by increasing the elevation. In addition, the lengths of the separation and reattachment zones were equal to 1.2–2.7 and 1.57–4.18 times the spur dike wing length.