Nonlinear dynamics of a piezoelectric wind energy harvester by exploiting vortex-induced vibration

In this paper, a piezoelectric energy harvester by exploiting vortex-induced vibration (VIV) under the influence of random wind excitation is designed and the associated nonlinear dynamics is investigated comprehensively. The dynamic equations of motion considering the inherent randomness, including the modified Hartlen-Currie model characterizing the random wind forces, are formulated for the piezoelectric energy harvester. Stochastic averaging method is then employed to derive the stationary distribution of mechanical states, providing insights into the long-term behavior of the system. Both the resonant case and the non-resonant case between Strouhal frequency of incoming wind with the natural frequency of the piezoelectric beam are investigated in detail. Performance metrics, including mean square electric voltage (MSEV) and mean output power (MOP), are theoretically obtained through the analysis. Parameter sensitivity analysis is applied to enhance efficiency, and the results are validated through comparisons with numerical simulation and wind tunnel experiments. The findings from this study offer valuable insights into optimizing the design and enhancing the reliability of piezoelectric energy harvesters under the influence of fluctuating wind conditions.