EFFECTS OF INCLINATION ANGLE ON 3D UNSTEADY FLOW STRUCTURES AROUND SUBMERGED SPUR DIKES

Abstract

3D turbulent flow structures around sub-merged spur dikes are numerically investigated focusing on the effects of the inclination angle. The basic equations of the numerical model are derived on a generalized curvilinear movable coordinate system with full-staggered arrangement of hydraulic variables. A 2nd order non-linear k-E model is adopted as a turbulence model to simulate the complex turbulent flows with separation and vortex shedding from the edge of the spur dikes. Numerical results are compared with the results in the PIV measurements by Tominaga et al (2001) and the model performance is examined. The present numerical model could reproduce the fundamental aspect of the 3D turbulent flow features influenced by the inclination angle of the spur dikes. The numerical results indicate that the amplitude of the fluid oscillation around the downstream inclined spur dikes is much larger than that around the upstream inclined ones. The period of the fluid oscillation is in compatible with the first mode in the impinging shear layer.