Energy harvesting from the gust response of membrane wing using piezoelectrics

Abstract

Micro-air vehicles face challenges in aerodynamic and endurance. This paper presents a novel gust response-based membrane wing energy harvester to solve these issues. An aero-electro-mechanical model based on CFD/CSD coupling method is established to investigate the dynamic response and the energy harvesting performance of this energy harvester under harmonic gust loads. The geometric nonlinearity of structure and aerodynamic nonlinearity are considered in this paper. The harmonic gust loads were obtained from a Navier–Stokes CFD solver based on unstructured meshes. The large deformation electro-mechanical finite element model was built based on the updated Lagrangian formulation and the principle of virtual work. The mean power density is defined to evaluate the energy harvesting performance. The effects of the external load resistance, the PVDF patch location, the gust amplitude and frequency, and Reynold number are studied, respectively. The results show that the optimal resistance of this energy harvester is 1.6kΩ, and the flexibility of the membrane wing improves the aerodynamic and energy harvesting performance greatly through increases the amplitude of odd super harmonics. The PVDF location has a relatively small impact on the energy harvesting performance except near end surfaces. The PVDF patch located at 0.1c–0.9c all can get better energy harvesting performance. When the equivalent angle of attack of gust amplitude exceeds 4 deg, the energy harvesting performance decreases slightly due to the formation and convection of leading-edge vortex. A sustained output power density of 5.31mW/cm3 is harvested at Re=25,000. The present work provides an effective theoretical basis for further studying energy harvesting of Micro air vehicles.