Unstable Oscillation of Rectangular Cylinder at Various Mass Ratios

Abstract

For aerodynamic unstable oscillations, the dynamic properties of a structural system have a strong influence on its response behavior. The mass-damping parameter (the product of the mass ratio and the damping factor), known as the Scruton number, has usually been employed to evaluate the occurrence of aeroelastic instabilities. Buildings and structures have become very light of weight and susceptible to wind-induced oscillations. Consequently, we cannot suppose that the dominant frequency of response is almost equal to the natural frequency of the structural system. Taking into consideration that various kinds of unstable oscillations appear in the heaving oscillation of a rectangular cylinder, a variation in the mass ratio may cause peculiar behavior of the structure, even if the Scruton number is constant. Thus, we must clarify the dependency of various unstable oscillations on the Scruton number and the mass ratio. The purpose of this paper is to investigate the above issues using three-dimensional sim...