Wind pressure analysis on a flat-roof building under the local acceleration wind profiles

This study examines wind pressure distributions on a flat-roof building subjected to a locally accelerated wind profile. Two sets of wind profiles are considered: (1) profiles defined by the height of the peak wind speed at 40%, 60%, and 80% of the building height (H), all under a constant acceleration factor of 1.1, and (2) profiles defined by a higher acceleration factor (1.3) at fixed peak heights of 0.4H and 0.8H. Relative to the traditional atmospheric boundary layer profile, the locally accelerated profile significantly amplifies windward surface pressures, particularly at elevations aligned with the acceleration zone. A higher acceleration region (H_acc) combined with a larger acceleration factor (β) results in increased wind pressures on the roof. For an acceleration factor of 1.3 with a fixed peak height of 0.8H, the area-averaged time-mean corner-region pressure coefficient rises by approximately 25.37% compared with the category A wind profile. The spectral proper orthogonal decomposition method is employed to analyze roof-surface vortical structures and successfully isolates energetically dominant coherent vortices exhibiting periodic behavior. Overall, these findings offer important guidance for the wind-resistant design of flat-roof buildings in complex flow environments, highlighting the coupled effects of accelerated flow and resulting pressure loads.