Numerical simulation on the process of the changing from the state of the Multi-articulated flat plat at rest to that at fluttering

Abstract

Multi-articulated flat plate which consists of some flat plates connected with smooth articulates is self-oscillated in a mean-flow. To clarify the oscillation mechanism analytically, the equation of motion on the multiple-pendulum was derived. The two-dimensional numerical simulations of fluid-structure interaction were conducted. In order to calculate the flow around the oscillating flat plate, moving overlap meshes were applied. In the results of the simulation, Multi-articulated flat plate started oscillation itself. At first the vorticity layer was formed behind the static plate and Kármán vortex street was appeared far from the trailing edge. Then the shear layer became wavy with longer wavelength than Kármán vortex. The flat plate was swayed and started fluttering. The three-dimensional simulation was also conducted, and Kármán vortex street was also appeared. However the wavy motion of the shear layer was not appeared and the flat plate did not fluttering.