Across-wind fluctuating aerodynamic force acting on large aspect-ratio rectangular prisms

Abstract

This work addresses the aerodynamic characteristics and spatial structure of the across-wind fluctuating aerodynamic force and its influence on wind-induced responses of rectangular prisms. Seven rectangular rigid models with different side ratios (1/4–4) are constructed, and simultaneous pressure tests are conducted in turbulent boundary layer flows. According to the measured data, separation and reattachment characteristics, span-wise correlation coefficients, and coherences are calculated, and then an empirical coherence function model is obtained. By comparing this model with traditional coherence models, the main factors affecting the coherence of the across-wind fluctuating aerodynamic force are presented and discussed. The proposed normalized coherence model takes into account factors such as the vortex shedding, side ratio, building feature size, the spatial location, and frequency correction. The non-dimensional joint acceptance function is presented, based on which the influence of the coherence function model on across-wind fluctuating wind load evaluation and wind-induced response analysis is compared and analyzed.