Vibration energy harvesting under concurrent base and flow excitations with internal resonance

In this study, internal resonance is investigated to further explore the potential of energy harvesting under concurrent base and flow excitations. The effects of system parameters on the performance of energy harvester with three-to-one internal resonance are analyzed analytically. At first, a lumped-parameter model for the energy harvester, which consists of a two-degree-of-freedom airfoil with the piezoelectric coupling introduced to the plunging motion, is established by using a nonlinear quasi-steady aerodynamic model. Subsequently, the method of multiple scales is implemented to derive the approximate analytic solution of the energy harvesting system under three-to-one internal resonance. Then, the bifurcation characteristics of the energy harvester with respect to various system parameters are analyzed. Finally, the numerical solutions are presented to validate the accuracy of the approximate analytic solutions. The study shows that the harvested voltage and power of the energy harvester can be significantly improved in the presence of internal resonance. In addition, the analytic solutions of internal resonance and the bifurcation analysis can provide an essential reference for design of such a kind of energy harvester.