Modeling the along-wind loading on a high-rise building considering the turbulence scale effects in the wind tunnel tests

Abstract

The three-dimensional (3D) stretch and distortion of the approaching turbulent flow will cause significant unsteady wind loads on line-like structures, such as high-rise buildings (HRBs). This phenomenon becomes more prominent when the scale ratio Lu/D (Lu is turbulence scale, D is body size) decreases, which is defined as the turbulence scale effect (TSE). Consequently, the traditional aerodynamic admittance (AAF) fails to estimate the along-wind loading (AWL) on HRBs, especially in wind tunnel tests. This paper studies the TSE on the AAF of an HRB with a 2:1 rectangular cross-section based on the pressure measurement of a segmental model. A 3D spectral method is presented to decompose the traditional AAF of AWL into the two-dimensional AAF (2D-AAF) in fully coherent gusts and the 3D correction factor to consider the 3D effect. The results indicate that the reduction of Lu/D will amplify the high-frequency decay slope of 2D-AAF and attenuate the low-frequency value of traditional AAF, determined by the distorted turbulence and the 3D effect, respectively. Notably, the presented 2D-AAF model based on the experimental data from grid-generated turbulence can be adopted to predict the unsteady AWL on a 2:1 HRB in the simulated boundary layer (ABL) flow accurately, confirming the uniqueness of the proposed model.