摘要

This paper presents an experimental investigation on 6-DOF vortex-induced motion response of a tethered buoyancy can under conditions of different tether lengths. The buoyancy can was mounted vertically, with the diameter of 150 mm and the length of 700 mm. The responses of trajectory, amplitude, frequency and other parameters were analyzed in detail under conditions of different tether lengths and height above the water. In addition, during the experiment, obvious yaw motion is observed and the yaw characteristics were investigated. The results show that when the reduced velocity is small (less than about 3.5), the motion amplitude is small and irregular and when the reduced velocity is large (3.5<U-r, <15), the in-line vibration frequency is two times the transverse vibration frequency and the trajectory of the cylinder is in "figure 8" shape. A strong connection between the yaw motion frequency and the vibration frequency was also found. Moreover, the mean drag coefficient of the buoyancy can was measured and the amplification effect of VIV on drag coefficient was observed.