An investigation of fluttering piezoelectric energy harvesters in off-axis and turbulent flows

The response of a fluttering piezoelectric energy harvester was studied in smooth flow and in aspects of replicated Atmospheric Boundary Layer turbulence (12.7% intensity, 310-mm longitudinal integral length scale). The harvester was yawed and pitched, and the effects on the power output were examined. Key findings were the following: (1) off-axis flow conditions rapidly degraded the mean output power of the harvester; (2) turbulence, for this specific harvester, acted similarly to a dynamic damping mechanism; (3) for on-axis flow, turbulence degraded the power outputs relative to smooth flow and for off-axis flow, the turbulence enhanced the power outputs relative to smooth flow. Future challenges include determination of harvester efficiencies, and analysis of fatigue-induced performance degradation.