The effect of wind characteristics on tall buildings with porous double-skin facades

Wind loads on tall buildings with porous double-skin facade (PDSF) systems were studied for various wind characteristics. Experiments were performed on a small-scale building model in a boundary layer wind tunnel. A single-skin building model was used as a reference case alongside three PDSF systems of 25%, 50% and 65% porosity. Two atmospheric boundary layer (ABL) simulations were created corresponding to category I (rural) and category III (suburban) ABLs of the EN-1991-1-4:2005 standard. Wind loads on the building model were studied based on high -frequency force balance measurements of integral moments, while pressure distribution on the building model surfaces was analyzed based on pressure measurements. Experiments were per-formed for ten flow incidence angles 0 degrees < alpha < 45 degrees with a 5 degrees increment. The obtained results are considered highly relevant both for research purposes and engineering applications, especially considering the lack of similar studies currently available. In particular, the rural ABL simulation yields larger mean pressure coefficients. The effect of the ABL characteristics on the pressure coefficient standard deviation depends substantially on alpha, while the most notable difference is observed on the windward building model surface at alpha = 0 degrees, where the suburban ABL causes a substantially higher standard deviation. The mean across-wind moment coefficient of the sub-urban ABL simulation is lower at all alpha points, while its standard deviation is lower for alpha > 0 degrees. The along-wind moment coefficient in the suburban ABL simulation is-20% lower than in the rural ABL simulation, a trend which is observed for all alpha points. In contrast, the along-wind moment standard deviation is-25% larger in the suburban ABL simulation. The power spectral density of the along-wind moment is considerably lower in the suburban ABL simulation.