Investigating the Effects of Aerodynamic Force Model on the Response of a Galloping PZT Energy Harvester

This paper studies the effects of higher order terms in aerodynamic force model on the mechanical and electrical responses of a galloping-based piezoelectric energy harvesters. The system composed of a piezoelectric bimorph cantilever beam with an attached bluff body and exposed to an incoming flow. The aerodynamic force is modelled based on the quasi-steady assumption. First, utilizing an experimentally validated parameters, the dimensionless aero-electromechanical governing equations of the system is provided for the cases of 3rd and 7th order aerodynamic model. Then, using a numerical integration method, the differences between the responses originating from the 3rd and 7th order aerodynamic force scenarios are studied. It is observed that the responses corresponding to the aforementioned models have a considerable difference, especially in the higher flow speeds. Then, an approximate-analytical solution based on the multiple the scales method (MSM) is obtained; the numerical observations are also verified by the MSM solutions. The results disclose that considering the higher order terms in the aerodynamic force expansion is necessary for the accurate characterization of the mechanical and electrical response of the system.