Marine energy harvesting from fluid flow via vortex induced vibrations

Abstract

• The study employed numerical simulation to evaluate the performance of the Vortex-induced Vibration (VIV) to Strain Energy (SE) Converter (VSD converter). The study also highlights the influence of spring stiffness, damping, and relative mass on VIV behavior, providing valuable data for converter design and optimization. • The research details the physical model of the VIVACE converter, including the governing equations for fluid dynamics and rigid body motion. Additionally, the solution domain, boundary conditions, and computational grids were investigated for accurate simulation. • The study examined the vibrations of a single-degree-of-freedom rigid cylinder with elastic support across a range of Reynolds numbers (Re) between 30,000 and 130,000. • The numerical simulation results were validated against experimental data. This validation confirmed the accuracy of the simulation approach, particularly for specific parameter settings. • The findings suggest an optimal configuration for VIV-based energy conversion. This configuration involves a spring stiffness of around 1200 N/m, zero damping, and a relative mass close to 1.89 within the studied Reynolds number range. This configuration maximizes the oscillation amplitude and energy extraction potential. This research study highlights into the dynamics of vortex-induced vibrations (VIV) in a rigid cylinder, employing computational fluid dynamics (CFD) simulations validated against experimental data. The primary objective is to explore the potential of harnessing energy from fluid flow-induced vibrations, particularly at lower flow speeds, which are traditionally overlooked by conventional turbine technologies. The CFD simulations investigated the transverse vibrations of a rigid cylinder with elastic support across a wide range of Reynolds numbers. The numerical results were compared with experimental data obtained from the University of Michigan, demonstrating strong correlation, especially for a spring stiffness of 1200 N/m, zero damping, and a relative mass of 1.89. Under these conditions, the maximum relative amplitude of 1.75 was achieved at a Reynolds number of 90,000. The study revealed that increasing spring stiffness up to 1200 N/m enhances the oscillation amplitude. However, further increases in stiffness lead to a decrease in amplitude. Damping and relative mass also significantly influence the vibration behavior. Lower relative masses and damping ratios result in larger amplitude oscillations over a broader range of Reynolds numbers. These findings underscore the feasibility and potential of energy extraction from fluid flows that were previously considered unsuitable. The quantitative insights provided in this study offer valuable guidance for the design and optimization of VIV energy converters. Future research should focus on long-term simulations to further elucidate the impact of these parameters on the performance and durability of such systems.