Analysis of Vortex-Induced Vibration For Enhanced Energy Harvesting From Nonlinear Cylinder System

With the rapid development of marine engineering, offshore renewable energy exploitation and marine structural safety have become key research priorities. This paper investigates the effect of nonlinear springs on the vortex-induced vibration (VIV) characteristics and energy harvesting efficiency of the rigidly-connected coupled double-cylinder system. Using computational fluid dynamics (CFD) and structural dynamics methods, along with overset mesh techniques, the vibration models for the 2-degree-of-freedom (DOF) system with nonlinear springs are developed. By varying the spacing ratio between the cylinders and the incoming flow angles, the system’s vibration response, power spectral density, fluid force coefficients, and vortex shedding and energy harvesting efficiency are analyzed. The study finds that nonlinear springs effectively increase the vibration amplitude and broaden the effective vibration range of the system, maintaining stable energy harvesting performance across a wide range of Reynolds numbers. The spacing between cylinders and the income flow angle significantly influence the VIV, and there is a notable correlation between these parameters and the system’s energy harvesting efficiency. This research provides theoretical support for the optimization of VIV energy harvesting systems.