Vortex-induced vibration and flow characteristics of a circular cylinder attached with inverted flexible and rigid splitter plates

In this study, inverted flexible and rigid splitter plates are applied to control the vortex-induced vibration of a circular cylinder. The VIV characteristics and vortex dynamics are experimentally investigated with a Reynold number ranging from 1970 to 10590. To examine the effect of the streamwise length, five different lengths are selected. It is indicated that the VIV of the circular cylinder is suppressed by the inverted rigid splitter plate and the suppression effect is improved with an increase in the streamwise length of the plate, however, the vibration response characteristics remain the same for all streamwise lengths. Compared to the rigid one, the inverted flexible splitter plate causes various vibration responses with the change of its streamwise length. The diverse vibration responses are related to the kinematic characteristics of the inverted flexible splitter plate and the vortex dynamics. Five vortex shedding modes, including “Kármán vortex”, “Bi-LEV + Bi-WV”, “2Bi-LEV + Bi-WV”, “Uni-LEV + Uni-WV”, and “K-H instability”, are found. The correlation between the VIV and the vortex shedding mode is revealed. The “Kármán vortex” and “K-H instability” modes are corresponding to a better effect of suppressing VIV. The control effect of “LEV + WV” modes is affected by the kinematics of the plate, as it is found that the vibration amplitude of the circular cylinder and the inverted flexible splitter plate is positively correlated.