Flow Driven Vibration Energy Harvester

This paper describes an energy harvester working with the repeated deflection of a piezoelectric cantilever. The harvester works in flowing media like wind or water. The bending of the cantilever is driven by vortices traveling across it. The presented device is an easy solution for vibration energy harvesting without the need of external mechanical vibration. The working principle was determined with macroscopic models in wind and water channels. The harvester does not need in general a mechanical adaption to the external vibration frequency, because it oscillates always with its resonance frequency at different flow velocities. Furthermore a self synchronization of cantilevers arranged beside each other could be observed in water. A second system was able to supply a load of approximatly 2 mW in a wind channel at a flow velocity of 8 m/s.