Abstract This work examines the spatial correlation of the along-wind aerodynamic fluctuating force and its influence on wind-induced responses of high-rise buildings. Seven rectangular rigid models with different side ratios (1/4-4) are made, and simultaneous pressure experiments are conducted under turbulent boundary layer flows. Using the measured data, span-wise correlation coefficients are calculated, and then empirical coherence functions are obtained. In comparing with the traditional coherence models, the main factors affecting the coherence of the along-wind fluctuating aerodynamic force are presented and discussed in this study. A normalized coherence model was proposed, considering factors such as the windward side width, aspect ratio, separation distance from the ground, and low frequency correction. Further, the nondimensional joint acceptance function is presented, based on which the influence of the coherence model on along-wind wind load evaluation and wind-induced response analysis is compared. Finally, for convenience of engineering application, a simplified formula consistent with the revealed coherence properties is recommended.

Graphical abstract Graphical abstract: This work addresses the spatial correlation of along-wind aerodynamic fluctuating force and its influence on wind-induced responses of tall buildings. Seven rectangular rigid models with different side ratios (1/4–4) are made, and simultaneous pressure tests are conducted in turbulent boundary layer flows. According the measured data, span-wise correlation coefficients are calculated, and then empirical coherence functions are obtained. By comparing with the traditional coherence models, main factors affecting the coherence of the along-wind fluctuating aerodynamic force are presented and discussed. A normalized coherence model has been proposed, which takes into factors including the windward side width, aspect ratio, the separation distance form the ground and low frequency correction. The non-dimensional joint acceptance function is presents, based on which the influence of the coherence function model on along-wind wind load evaluation and wind-induced response analysis is compared and analyzed. Finally, for the convenience of engineering application, a simplified formula is recommended that is basically consistent with the coherence properties revealed in this study. The proposed Coherence function modelDistribution of non-dimensional joint acceptance function versus aspect ratio m. Display Omitted

Highlights • Coherence functions of rectangular prisms with different side ratios are compared and distinguished using the $\Delta z/\bar{U}$ as a preliminary parameter. • A normalized coherence model is proposed that considers several factors including turbulence length scale, aspect ratio, low frequency, and spatial size correction. The proposed model is found to better describe coherence and to have a clearer physical meaning than existing models. • The influence of the proposed model on the joint acceptance function is presented and compared with previous models, including that of Davenport. Findings show that the Davenport model can be simplified and optimized by setting its decaying coefficient $c_u^{\Delta z}=6$.