INVESTIGATION OF TWISTED WIND EFFECT ON A SQUARE-SECTIONAL SUPER-TALL BUILDING

Super-tall building is sensitive to wind loading because of its light weight and high slenderness. Under the influence of topography and Coriolis force, the wind direction may change along the height, which is known as the twisted wind effect. In the wind tunnel test and numerical simulation of this study, the twisted wind fields (TWFs) with different yaw angles were generated following the Ekman spiral model. Wind effects on a square-sectional super-tall building under twisted wind and those under the conventional wind fields (CWFs) were analyzed. The results showed that: under the twisted wind effect, the wind pressure distribution on the building facades became asymmetrical. In addition, the values of the base moment coefficients and the local wind force curve may need to be reconsidered in TWF-resistant designs. Numerical simulation showed that only the TWFs with a maximum yaw angle over 10° may induce notable effect on the pressure distribution on building facades. Furthermore, by means of proper orthogonal decomposition (POD) and of flow field analysis, the mechanism of TWFs was explained. This study aims to provide a useful reference for wind-resistant design of super-tall buildings under twisted wind effect.