The role of Permeable Double Skin Façades on the onset of VIV on high-rise buildings

The application of stand-alone permeable screens for the mitigation of vortex shedding problems is a well-known option in wind engineering, usually adopted for bridges. Nevertheless, their employment in buildings is still in its early stages. Porous coverings are employed for aesthetic reasons and, recently, also for their capability to reduce the energetic impact of the building. Within this framework, the Permeable Double Screen Façades (PDSFs) are becoming popular in the architectural trends, but their effects on the building’s aerodynamics are still an open topic. Specifically, it is still unclear which could be the role of the permeable layer on the vortex shedding mechanism, which currently represents one of the main design issues for tall and super tall buildings. The present study proposes an experimental investigation of the role of the PDSF in the vortex-induced vibrations (VIVs) of a prismatic building model with an aspect ratio $B/D=3.33$. A semi-aeroelastic model of the building is tested for different Scruton numbers and a comparison between the PDSF and the solid façade case is proposed. Results highlight that the effectiveness of the PDSF in structural response mitigation appears to be dependent on the Scruton number and a threshold over which the PDSF successfully mitigates the onset of VIV is found.