Escape of a circular cylinder from a potential well via nonlinear vortex-induced vibrations: An experimental investigation

In this study, the basic characteristics of escape from a potential well is investigated experimentally for a circular cylinder undergoing vortex-induced vibrations for Reynolds number ranging between 1000 and 5000. The experimental system consisted of a circular cylinder suspended by two elastic beams and allowed to oscillate in the vicinity of two attracting magnets. The shape of the system’s restoring force and the height of the potential energy barrier are controlled by changing the distance between the magnets and the oscillating cylinder. Escape occurs when the oscillating cylinder overcomes the potential barrier and collapses onto one of the attracting magnets. It is shown that, escape can occur in a range of flow velocities bounded by two speeds, U1