Experimental investigation to dynamics of wavy cylinders in cross flow

The effects of different degrees of obliqueness of wavy cylinders on flow-induced vibration suppression on cylindrical structures were experimentally investigated. The experiments were carried out in a low speed wind tunnel with 0.6 m × 0.6 m cross-section and free-stream turbulent intensity less than 0.2%. The Reynolds numbers, based on the free-stream velocity and the nominal cylinder diameter, varied within 2.0 × 10⁴ to 5.0 × 10⁴. The measurements of fluctuating forces and Strouhal numbers induced by a cross flow over three kinds of wavy cylinders were implemented. It is concluded that the root-mean-square (RMS) fluctuating lift coefficients of the wavy cylinders are much lower than those of right cylinders, which means a good effect of wavy cylinder on the suppression of flow-induced vibration. The spectral analysis of both hot-wire and load cell signals indicates that the Strouhal numbers of the wavy cylinders are naturally identical with ones of the corresponding circular cylinder, thus the vibration suppression capacity of wavy cylindrical structures is not resulted from the variation of Strouhal number.