A 2DOF galloping oscillator with internal resonance for broadband concurrent wind and base vibration energy harvesting

Abstract

Studies regarding concurrent wind-flow and base-motion energy harvesting have drawn increasing attention in recent years. However, for conventional wind energy harvesters under such dual excitations, the base-excited inertial vibration and flow-induced aeroelastic vibration supplement with each other only within a narrow range of frequency near the resonance. Within this range, aeroelastic vibration frequency is locked into the base vibration frequency where the two sources are concurrently contributing to power generation; while the concurrent feature is lost outside this range. Internal resonance in multimodal systems has been utilized in recent years for efficiency improvement in pure base vibration energy harvesters. The merit comes from the fact that energy can be pumped from other modes to the power generation bandwidth, broadening the bandwidth toward both lower and higher frequency regions. In this paper, a broadband galloping-based aeroelastic energy harvester with internal resonance is proposed for the purpose of efficiency enhancement in concurrent wind and base vibration energy harvesting. Two-to-one internal resonance is aroused by arranging two sets of magnets symmetrically at the beam connection. Numerical solutions are calculated for the fully coupled aero-electro-mechanical model. A significantly widened lock-in bandwidth with multiple power peaks is achieved for effective concurrent wind and vibration energy harvesting.