Improving energy harvesting in flow-induced vibrations of multi-cylinder square arrays with vortex generators

Abstract

Energy harvesting from flow-induced vibrations (FIV) offers a promising pathway for renewable energy systems, enabling the conversion of mechanical energy into electrical power. Multi-cylinder FIV configurations, particularly in hydrokinetic applications, exhibit significantly higher energy harvesting efficiency compared to traditional single-cylinder vortex-induced vibrations (VIV). To evaluate their potential for optimizing energy conversion, three multi-cylinder configurations are systematically investigated using high-fidelity computational simulations within the present study. The baseline configuration consists of four identical elastically mounted cylinders arranged in a square formation. To enhance the energy harvesting efficiency, a novel strategy is proposed, utilizing large fixed upstream cylinders as passive vortex generators. The findings reveal that fixed cylinders generate coherent vortices, synchronizing the oscillation frequencies of downstream cylinders and significantly increasing their vibration amplitudes and energy extraction efficiency. Additionally, increasing the gap spacing between cylinders reduces inter-cylinder interactions, stabilizing their wake dynamics and further improving system performance. Compared to the baseline configuration, the optimal configuration achieves remarkable power harness efficiencies, offering practical insights for designing highly efficient renewable energy technologies leveraging FIV.