Harvesting wind energy with a bi-stable configuration integrating vortex-induced vibration and galloping

This paper proposed a wind energy harvester that integrates the merits of vortex-induced vibration (VIV), galloping and multi-stability. Two different shapes of bluff bodies are introduced to induce VIV and galloping for incoming flow, respectively. Three magnets are placed on the beam and fixture so as to generate bi-stability by magnetic attraction. As the wind blows through, the induced aero-dynamical instability leads the piezoelectric beam to oscillate and execute snap-through motion, which could generate a large electric output. The validation experiment was conducted. The experimental results show that as the flow speed increases from v= 1.0 m s-1 to 7.0 m s-1, the harvester could begin snap-through motion from a low speed v = 1.5 m s-1, and maintain the coherence resonance motion within a broad range of wind speed. Thus, it could maintain the large output in the environment of variable-speed wind.