Performance of an omnidirectional piezoelectric wind energy harvester

This paper presents a vortex-induced vibration (VIV)-based piezoelectric energy harvester that performs well for all wind directions, a so-called omnidirectional wind energy harvester. The kinetic energy of this harvester stems from wind-induced vibrations of a circular cylinder mounted on an orthogonal bibeam system, rather than a traditional single beam. Wind tunnel testing results show that compared to the traditional single-beam energy harvester, the proposed harvester substantially enhances the effectiveness, in most cases that the beam is skew to the incoming flow. The reasons for the enhancement are explained in detail by examining the wind-induced displacement response components of the cylinder identified by the image processing technique. For all wind directions, both the maximal output energy and the range of effectively working wind speed of the proposed bibeam wind energy harvester are significantly improved with respect to the single-beam system, indicating excellent performance of the proposed omnidirectional harvester in a natural wind environment.