Performance enhancement for a magnetic-coupled bi-stable flutter-based energy harvester

This paper aims at presenting a novel magnetic-coupled bi-stable flutter-based energy harvester (MBFEH) for the purpose of enhancing power generation in low speed air flow. The MBFEH comprises of a piezoelectric beam with a magnet on its tip, a hinged rigid flat airfoil, and an external magnet. The magneto-electro-aeroelastic system is theoretically modeled, numerically investigated, and experimentally validated. The influences of the separation distance between the magnets on flutter characteristics and performance of power generation are studied. The numerical and experimental results show that the supercritical flutter will be transformed into the subcritical flutter which realizes a significant reduction of cut-in air speed for energy harvesting. Compared with the conventional flutter-based energy harvester, the cut-in air speed of the MBFEH is reduced by more than 50% when the separation distance is set as 15 mm. The most preferred distance among the tested configurations is 12 mm which broadens the usable air speed by 1.8 m s-1, and leads to a 102% improvement of the energy harvesting performance throughout the air speed region from 2 m s-1 to 6.6 m s-1. The study shows that the proposed MBFEH is an effective design approach for enhancing energy harvesting capability in low air speed range.