Experimental Investigation of Unsteady Aerodynamic Forces and Vortex-Induced Aeroelastic Effects of a Slender Structure in Uniform and Turbulent Flows

Abstract

Slender structures are sensitive to wind loads, and aeroelastic effects during vortex-induced resonance have considerable influences on their survivability, serviceability, and habitability. However, the vortex-induced aeroelastic effects and the effects of turbulence intensity on unsteady aerodynamic forces of an aeroelastic prism remain far from been fully understood. In this study, a series of wind tunnel tests, including the pressure measurements of a rigid model and simultaneous measurements of the pressure and response of an aeroelastic model, were conducted in three different wind flows. The characteristics of unsteady aerodynamic forces and the effects of turbulence intensity on the unsteady aerodynamic forces were systematically investigated. The mechanism of aeroelastic effects and the variations of aerodynamic damping ratios were also discussed. Wind-induced responses were predicted by the unsteady aerodynamic forces and compared with the measured values. The experimental results show that vortex-induced aeroelastic effects on the wind-induced responses and the unsteady aerodynamic forces are significant. An increase in the turbulence intensity may result in a weak correlation of the unsteady aerodynamic forces and thus suppress the vortex-induced aeroelastic effects. Moreover, the amplitudes of the positive and negative peaks of the aerodynamic damping ratios decrease with the increase of the turbulence intensity. In addition, the wind-induced responses predicted by the unsteady aerodynamic forces measured from the aeroelastic model are the closest to the measured responses.