Energy harvesting using piezoelectric sheet fixed on a flexible plate attached to a cylinder in free stream flow

We experimentally investigate the piezoelectric energy harvesting of ambient wind energy due to the flow-induced vibration of a flexible plate. A piezoelectric sheet is glued on a thin flexible plate and the composite plate is attached to a lee side of a circular cylinder subjected to a free stream flow. We study seven cases of this simple configuration, comprising only a piezoelectric sheet and a piezoelectric sheet pasted on flexible plates with varying lengths and thicknesses. The wind velocity and the external load resistance are varied in the range of 4.8–17.1 m/s and 5–100 kΩ, respectively, to test a large range of practical conditions. We describe the plate dynamics by analyzing the displacement, frequency response, phase plane, and oscillation envelopes. In addition, voltage and power output are recorded and analyzed. Furthermore, we illustrate the energy budget assessment and estimate the efficiency of the system. An optimum load resistance for the maximum power output and an optimum velocity for the maximum transduction efficiency are found in the lock-in regime. The maximum power output (order of mW) is observed at different ranges of flow velocities for different cases. Furthermore, a piezoelectric energy harvesting circuit is designed to demonstrate the harvested energy can power multiple light-emitting diodes. The piezoelectric sheet pasted on the flexible plate, therefore, increases power output by two to three orders of magnitude compared to only using a piezoelectric sheet.