Aerodynamic loads of tapered tall buildings: Insights from wind tunnel test and CFD

Tapered modifications have been widely utilized for tall buildings to reduce their wind effects in practical engineering. However, the flow mechanisms caused by tapering and relevant empirical models for wind loads estimations of tapered tall buildings are still unknown. In this study, both wind tunnel test and CFD were used to study the aerodynamic performance of tapered tall buildings. Taken the CAARC standard tall building model as the benchmark model, another four modified models with taper ratio of 0.05, 0.10, 0.15 and 0.20 were designed and tested by pressure measurements and large eddy simulation (LES). The variations of wind pressure coefficients, local wind force coefficients, base moment coefficients, wind load power spectrum and vertical coherence function of five models with different taper ratios were discussed and compared. Also, the streamline of mean and fluctuating velocity around tapered tall building models are provided for better understanding of the flow mechanisms. The results showed that aerodynamic performance of the tapered tall buildings has been improved effectively, especial for across-wind effects. This study aims to provide reference for aerodynamic optimization design of tapered tall buildings. © 2023 Institution of Structural Engineers