Effects of Attached Afterbody Shapes on Wind Forces on Rectangular Tall Buildings

ABSTRACT The knowledge of aerodynamic forces has important implications for the wind‐resistant design of tall buildings. At present, the aerodynamic characteristics of conventional rectangular‐shaped tall buildings have been extensively studied, while those of irregular‐shaped tall buildings have received relatively less attention. Therefore, in the current study, several tall building models are designed to investigate the aerodynamic characteristics of a rectangular tall building with and without attaching different shapes of afterbody. The influences of the afterbody shapes (i.e., semicircle, rectangle, and triangle attached to a rectangular tall building called the basic model in this paper), atmospheric boundary layer (ABL) flows, and models' aspect ratios on the aerodynamic forces are analyzed and discussed in detail based on wind tunnel test of pressure measurements on the models. It is shown that the attached afterbodies can significantly increase the local fluctuating lift coefficients and base fluctuating moment coefficients comparing to those of the basic model. Moreover, a larger aspect ratio causes the increase of local fluctuating lift coefficients and base fluctuating moment coefficients of the basic model attached with rectangular afterbody in suburban terrain. On the other hand, the above increases are strongly attenuated or even suppressed by the ABL flow over urban terrain. The results of this study are expected to provide useful information for the wind‐resistant design of irregular‐shaped tall buildings.