Flow–structure Interactions and Interference Effects on Asymmetric Twin-tower and Single-tower Buildings under Wind Loads

Based on a boundary-layer wind tunnel test on a Category C terrain, this study investigated the wind-induced pressure and load characteristics of an asymmetric twin-tower building and its corresponding isolated single-tower counterparts. The height ratio of the asymmetric twin towers was ۱.۲۶, and the Reynolds number of the test model was Re = ۸.۴×۱۰۴. Normalized by the characteristic tower width B = ۴۷ m, the dimensionless streamwise and transverse spacings between the two towers were ۰.۰۳۶ and ۰.۳۸۷, respectively. The study focused on the effects of aerodynamic interference on mean and fluctuating wind pressures, Gaussian/non-Gaussian characteristics, spectral features, and global wind loads and base moment responses. The results showed that aerodynamic interference modified both local pressure distributions and global responses in a markedly tower-dependent manner. In particular, the shorter upstream tower exhibited a pronounced asymmetric pressure pattern over the upper windward region (approximately ۱۸۰ m from the top). Moreover, the maximum mean negative pressure on its leeward face reached approximately -۱.۲, and the maximum fluctuating wind pressure reached approximately ۰.۴۲, both of which are significantly higher than those of the corresponding isolated short tower. Meanwhile, its low-frequency energy increased, and its sensitivity to wind direction also significantly increased. The range of its along-wind base moment coefficient in the phase plane trajectory reached ۰.۸۴, which is larger than that of the isolated short tower by ۰.۱۶. Furthermore, its along-wind and crosswind base moments showed strong negative correlations at the wind directions of ۹۰° and ۲۴۰°, with a correlation coefficient of -۰.۶۸. These results indicated that, in asymmetric twin-tower systems, the shorter upstream tower may be the more critical control object under aerodynamic interference. The findings provide a physical basis and engineering reference for the wind-resistant design of irregular multitower buildings.

کلیدواژه ها:

Asymmetric twin-tower ، High-rise building ، Wind-induced response ، Aerodynamic interference ، Non-Gaussian fluctuations ، Wind-resistant design