Beyond the critical nutter speed, an airfoil undergoes aeroelastic limit cycle oscillations that are determined by structural and aerodynamic nonlinearities. These oscillations are significant at high angles of attack in the dynamic stall range. This effort explores the potential of extracting energy from pitching and plunge motions during stall-induced oscillations. A mathematical model is developed to determine the coupled influence of harvesting energy from both pitching and plunging motions, and the extent to which structural nonlinearities impact the levels of harvested energy. The computational model is based on the equations of motion of a typical aeroelastic section with two degrees of freedom. The equations of an electrical generator connected to the pitching and a piezoelectric element connected to the plunging motion are coupled. Aerodynamic loads are given by the Beddoes-Leishman semi-empirical model. The results show that the harvested energy levels are strongly coupled. Furthermore, chaotic responses are noticed within certain ranges of airspeed.
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