Wind load reduction effects on inner buildings by exterior porous façades

• Published in: Building and environment 2020-10, Vol.183, p.107148, Article 107148
• Main Authors: Lo, Yuan-Lung, Wu, Yu-Ting, Fu, Chung-Lin, Yu, Ying-Chang
• Format: Article
• Language: English
• Subjects: Amplification; Buildings; Channel pores; Exterior porous façade; Facades; Façade gap; Fluid dynamics; Fluid flow; Pores; Porosity; Porosity percentage; Porous opening shape; Reduction; Reynolds number; Skin; Wind effects; Wind loads; Wind pressure; Wind tunnel testing; Wind tunnels
• ISSN: 0360-1323; 1873-684X
• DOI: 10.1016/j.buildenv.2020.107148

Modern architects often adopt the use of façades on new buildings or to improve the appearance of an existing old building. Among various types of facades, ones with porous skins are increasingly popular. The porous features can not only improve the aesthetic of design but can also significantly lower wind loads on the inner building. This research investigates the filtering performance of various exterior porous façades on the surface pressures of an ordinary building based on systematical wind tunnel tests. Three target parameters, the porosity percentage of the façade, the gap distance between the façade and the building surface, and the opening shape of the pores, are investigated in this study. Preliminary results show that the Reynolds number makes little difference to the measured mean and root-mean-square values of fluctuating pressures. Subsequent results show that the façade skin porosity and gap distance together contribute to any amplification or reduction of surface pressures measured on the inner building. Different reduction or amplification levels are also found highly related to the upstream or downstream region over the side faces for the mean and the fluctuating pressures. For a limited area near the building corners, an amplification in negative local pressures was found due to the flow entering the façade cavity on the windward face and being channeled between the façade and sidewall of the building. A channel-effect phenomenon is also indicated with the presence of the exterior skin in certain regions, instead of just the reducing effect from the pores. •This study investigates the filtering effect of porous façade skins on wind loads over the building surface.•Reynold number effect on the filtered wind loads is shown to be less sensitive when it is greater than the 6 × 104.•Porosity percentage and gap distance dominate the amplification or reduction effects over different surface regions.•A channel-effect phenomenon is observed due to the exterior skin, implying a mixed filtering mechanism.