Fluid–structure interaction in piezoelectric energy harvesting of a membrane wing

Abstract

Flow-induced vibrations (FIVs) can be utilized to harvest energy for micro-aerial vehicles. The purpose of this paper is to investigate the fluid–structure interaction in piezoelectric energy harvesting. A piezoelectric energy harvester for a membrane wing at Reynolds number Re = 8000 is studied based on an aero-electro-mechanical model using the computational fluid dynamics/computational structure dynamic coupling method. The updated Lagrangian formulation is applied for the large deformation of the flexible structure. The effects of the location of piezoelectric harvesters and the angle of attack (α=4∘–24°) on FIV response and energy harvesting performance are investigated. Average power density is defined to evaluate the energy harvesting performance of the harvester. The location of the piezoelectric harvester has a negligible effect on the energy harvesting performance under the same FIV response. However, the change in local stiffness caused by the location of the piezoelectric harvester may induce a noticeable difference in FIV response which impacts the energy harvesting performance. The simulation results indicate the strong coupling relationship among flow field, membrane structure, and electric field. There are two states of fluid–structure interaction at the angles of attack investigated. At α=4°–12°, the vibration response of the membrane wing is mainly driven by the natural frequency of the structure. At α=16°–24°, the convection and shedding of leading- and trailing-edge vortices play a dominant role in FIV response. The work presents the mechanism of fluid–structure interaction in energy harvesting from FIVs and provides a significant basis for designing energy harvesters of membrane wings.