Impact of system and stochastic parameters on the performance of a 3-DOF energy harvester in a two-dimensional flow field

This study develops a dynamic model for a three-degree-of-freedom aeroelastic flutter-based piezoelectric energy harvester in a two-dimensional unsteady flow field. Dimension reduction approach based on high-dimensional multi-stable system analysis is employed to investigate the system’s nonlinear dynamics. Deterministic analysis reveals that subcritical bifurcation can induce limit cycle oscillations at speeds below the cut-in speed. Further analysis using energy potential well theory demonstrates that improper selection of nonlinear stiffness parameters can create excessively deep potential wells, trapping the system and reducing energy harvesting efficiency. To account for stochastic effects, stochastic averaging is applied to derive the steady-state probability density function of the system in a two-dimensional stochastic flow field. The influence of stochastic flow disturbances on system behavior is examined, showing that longitudinal inflow disturbances significantly impact system stability. As transverse inflow disturbances increase, the harvester undergoes stochastic P-bifurcation, leading to large-amplitude oscillations and sustained energy output. These findings provide insights into the effects of system parameters and random disturbances on energy harvesting performance, offering a theoretical foundation for designing flutter-based energy harvesters.