Experimental investigation of downburst-induced wind loads on rectangular high-rise buildings: Influence of geometric features

Downbursts are intense, short-duration wind events commonly associated with thunderstorms and are known to generate highly localized, near-ground wind loads that can significantly affect the structural safety of high-rise buildings. Despite their destructive potential, the aerodynamic effects of downbursts have not been fully incorporated into conventional design practices. This study investigates the surface pressure distribution and aerodynamic force characteristics of high-rise buildings subjected to steady-state downburst wind fields, with a specific focus on the influence of geometric parameters—namely, height-to-width (H/B) and depth-to-width (D/B) ratios. Experiments were conducted using an impinging jet wind tunnel system capable of reproducing localized, near-ground peak wind features typical of thunderstorm downbursts. Eight rigid building models with systematic variations in H/B and D/B were tested across multiple radial locations. Surface pressure data were used to compute both local and overall aerodynamic force coefficients. The results show that the peak horizontal wind speed occurs at a radial distance of r/Djet = 1.0. The turbulence intensity exhibits an inverse relationship with the mean wind speed and follows a vertical trend of first decreasing and then increasing with height. Increasing H/B significantly reduces mean and fluctuating drag forces and results in smoother lateral load distributions, while D/B modulates suction intensity on roof and rear façades. The findings enhance the understanding of shape-dependent aerodynamic behavior in downburst conditions and provide practical insights for wind-resistant design of high-rise buildings in thunderstorm-prone regions.