Aerodynamic performance of a sinusoidal wavy cylinder at subcritical and critical Reynolds numbers

Abstract

Previous studies have shown that in the subcritical regime, wavy circular cylinders exhibit less wind-induced drag than standard circular cylinders. However, the aerodynamic performance of wavy cylinders at higher Reynolds numbers is still unknown. Hence, a series of wind tunnel tests including measurement of the surface pressure, vortex-induced vibration (VIV) and dry galloping were conducted for a wavy cylinder and a corresponding standard cylinder at Re = 1.00 × 105-3.86 × 105. The results indicate that the aerodynamic characteristics, including the mean and fluctuating pressure distributions, mean and fluctuating aerodynamic force coefficients, Strouhal number, flow regime classification, and non-Gaussian characteristics, are significantly modified when shifting from the standard cylinder to the wavy cylinder. Furthermore, these modifications highly depend on the Reynolds number. Regarding the wavy cylinder, related parameters obviously vary along the spanwise direction, indicating three-dimensional aerodynamic characteristics. Moreover, the maximum VIV amplitude of the wavy cylinder is 40% lower than that of the standard cylinder. The velocity corresponding to the maximum amplitude is increased by 11% for the wavy cylinder. Additionally, the maximum dry galloping amplitude is reduced by 11%.