A coupled model for vortex induced vibration of a circular cylinder with and without passive-jet flow control

In the present study, a coupled wake oscillator dynamic equation was established to predict the vortex-induced vibration (VIV) response of a circular cylinder immersed in a fluid. A classical structural dynamic equation was applied to describe the one-degree-of-freedom vibration of a circular cylinder. The revised van der Pol equation was used to model the wake flow dynamics and the fluctuating aerodynamic force derived from periodic alternating vortex shedding. The coupled structural dynamic equation and revised van der Pol equation were utilized to describe the features of VIV, such as the frequency component of aerodynamic forces, vibration amplitude, and lock-in domains. The results show that the proposed model can more precisely predict the VIV response and frequency features. An experiment was performed to study the passive jet flow control for VIV of a circular cylinder. The surface pressure distribution was measured to obtain the sectional aerodynamic forces acting on the model containing passive jet rings with different distances. The influencing range of the aerodynamic force caused by the passive jet rings was obtained and incorporated into the coupled model. The revised coupled model was found to predict well the VIV response of a circular cylinder equipped with adjacent passive jet rings having different distances.