Nonlinear energy sink-based study on vortex-induced vibration and control of foil-cylinder coupled structure

Abstract

The interference of blade wake flow can pose a threat to the safety of flexible tower structures. In order to investigate the influence of airfoil position parameters on the VIV characteristics and the vibration reduction effect of nonlinear energy sinks (NES) on the cylinder, a flexible tower under the influence of blade wake flow is used as a reference, and a dynamic simulation model of an airfoil-twin degree-of-freedom cylindrical coupled structure is established based on computational fluid dynamics (CFD), structural dynamics, and nested grid techniques. The accuracy of the numerical model established in this paper is verified by comparing it with experimental data from foreign literature. The calculation results indicate that airfoils in different positions cause changes in the amplitude and frequency ratios of the cylinder and can either delay or enlarge the frequency lock-in interval of the cylinder. Under the influence of airfoil wake, the column experiences more severe vibrations. The NES can absorb the vibrational energy of the cylinder, and setting appropriate NES parameters can reduce the resonance response between the cylinder and the shedding vortices in the wake of the airfoil. This helps to change the shedding mode of the vortex and effectively suppress the VIV of the cylinder.