On-off switching of vortex shedding and vortex-induced vibrationin crossflow past a circular cylinder by locking or releasinga rotational nonlinear energy sink

We show how fully developed vortex-induced vibration (VIV) of a linearly sprung circular cylinder can be completely suppressed, i.e., driven to zero asymptotically in time, by release of a rotational nonlinear energy sink, consisting of a mass rotating about the axis of the cylinder and a dissipative element damping the rotational motion of the mass. (The nonlinear energy sink is located either inside the cylinder or beyond the spanwise extent of the flow, with which it thus interacts only through inertial coupling to the rectilinear motion of the cylinder.) We also show that VIV can be turned on by locking up the rotating mass. Once VIV is suppressed or turned on, no further action or energy input is required. Thus, this approach provides a true switch. Applications for flow control and for turning mixing on or off are discussed.National Science Foundation (U.S.) (Grant No. CMMI-1363231