Abstract
In the authors’ previous report, a new wind energy harvesting method using flexible piezoelectric films bonded on the surface of a flexible cylinder, termed as Piezoelectric Cylindrical Shell-type Wind Energy Harvesting Flag (PCSWEHF) was proposed. In order to overcome the low power generation of the piezoelectric wind energy harvesting method at small wind speeds, vortex-induced vibrations (VIVs) of the flexible cylinder excited by the Karman vortex generated downstream of PCSWEHFs was used and it was shown in the preliminary experiment that more than ten times larger power was generated by PCSWEHFs compared with the conventional planar-type piezoelectric energy harvesting flags. However, the mechanisms and the conditions needed to cause the synchronization phenomena were still not clear. In this study, natural frequencies of the PCSWEHF and vortex shedding frequencies were derived from theoretical analyses and fundamental fluid dynamics theories, and by comparing these results, the method to construct superior PCSWEHFs which could generate large power at low wind speed was investigated.
