Suppression of Vortex-Induced Vibration Caused by A Terebridae-Inspired Cylinder with Different Helical Angles.

Biomimetic design has recently received widespread attention. Inspired by the Terebridae structure, this paper provides a structural form for suppressing vortex-induced vibration (VIV) response. Four different structural forms are shown, including the traditional smooth cylinder (P₀), and the Terebridae-inspired cylinder with the helical angle of 30° (P₃₀), 60° (P₆₀), and 90° (P₉₀). Computational fluid dynamics (CFD) method is adopted to solve the flow pass the Terebridae-inspired structures, and the vibration equation is solved using the Newmark-β method. The results show that for P₃₀, P₆₀ and P₉₀, the VIV responses are effectively suppressed in the lock-in region, and P₆₀ showed the best VIV suppression performance. The transverse amplitude and the downstream amplitude can be reduced by 82.67% and 91.43% respectively for P₆₀ compared with that for P₀, and the peak of the mean-drag coefficient is suppressed by 53.33%. The Q-criterion vortices of P₃₀, P₆₀, and P₉₀ are destroyed, with irregular vortices shedding. It is also found that the boundary layer separation is located on the Terebridae-inspired ribs. The twisted ribs cause the separation point to constantly change along the spanwise direction, resulting in the development of the boundary layer separation being completely destroyed. The strength of the wake flow is significantly weakened for the Terebridae-inspired cylinder. [ABSTRACT FROM AUTHOR]