Influence of boundary conditions on a flutter-mill

• DOI: 10.1016/j.jsv.2020.115359
• Publication Date: 2020-04-05T19:46:41Z
• Authors: A. Yamano; A. Shintani; T. Ito; C. Nakagawa; H. Ijima
• Keywords: Flutter; Vortex-induced vibration; Vortex shedding; Flapping; Vortex sheet; Potential flow

Abstract This study reports on numerical simulations of the flow-induced vibration of a sheet by considering geometrical nonlinearity and wake shedding from the trailing edge. Recently, a few studies proposed energy harvesters using flow-induced vibration, which is termed as “flutter-mill”. Preceding studies employed numerical models that are approximated by two-dimensional flow or slender body approximation to evaluate an energy harvester. The models exhibit a limitation in the application range of the aspect ratio. We employ the three-dimensional model that is modelled by the finite element method with absolute nodal coordinate formulation and unsteady vortex lattice method. The equation of motion for a flexible sheet exhibits Kelvin–Voigt-type material damping to emulate the effect of coupling between a sheet and the energy harvesting circuit. The numerical model under the uniform flow is compared with that in a preceding study to verify the flapping behavior of the model. We use the validated simulation model and investigate the relationship between material damping, flapping behavior, boundary conditions, and energy harvested from the fluid. Furthermore, we confirm that the pinned boundary condition of a flexible sheet is superior to the clamped boundary condition for energy harvesting.