Instability and Control of Massively Separated Flows

Abstract

Experiments have been carried out on models of free-to-rotate parallel and oblique plates fitted to a rigid section of circular cylinder to investigate the effect of plate length and oblique angle on the stability of this type of VIV suppressor. Measurements of the dynamic response by trajectories of motion are presented for models with lowmass and damping, free to respond in the cross-flow and streamwise directions. It is shown that, depending on a combination of geometric parameters devices might not be able to completely suppress VIV for the whole range of reduced velocities investigated. Plates with larger oblique angles turned to be less stable than parallel plates and induced high-amplitude vibrations for some specific reduced velocities.