Wind Force Characteristics of Square Cylinders with Sections of Height Variations

Abstract

Many researches on reducing wind-induced excitations of tall buildings have been carried out. One way to reduce the excitations is an aerodynamic modification of sectional shapes with height through tapering or set-back. In this paper, to investigate the mechanism of aerodynamic force reduction, high-frequency force-balance test was conducted. Two types of tapered models with different tapering ratios, a set-backed model and a prototype model of a square cross-section, were employed under two typical boundary layers. From the results, changing cross section helps to reduce the mean drag force and the fluctuating lift force. And the power spectra of tapered and set-backed models are wider than that of square prism.