境界層流中における高層建物の空力不安定振動

Abstract

To consider aeroelastic instabilities of prismatic high-rise buildings in strong winds, I.e., vortex induced oscillation or galloping, unsteady aerodynamic forces must be investigated as the external forces acting on buildings.From this point of view, wind tunnel experiments were performed to obtain the information of the unsteady cross wind moments as modal forces on buildings, which are subjected to the forced harmonic oscillation with a fundamental linear mode in a turbulent boundary layer.Unsteady moments are mainly produced by the suction forces generated by motion-induced vortices and by the vortex shedding behind buildings at rest, I.e., the vortex shedding of the Strouhal component, of which strength are varied with the oscillating amplitudes and the velocity of the incident flow.We investigated the characteristics of the unsteady moments varing with the amplitudes and the velocity and elucidated the mechanism of the motion-induced oscillation, by examining the arrangement, the frequency of occurrence and the interference effect of the two types of shedding vortices.