From vortex shedding to Vortex-Induced Vibrations: The role of porous façades

This work examines the aerodynamic and aeroelastic effects of a porous envelope applied to a rectangular prism with aspect ratio B/D=3.33, representative of a high-rise building. Wind tunnel tests on rigid and aeroelastic models were combined with Large-Eddy Simulations (LES) using a Darcy-Forchheimer homogenized representation of porosity. On the rigid model, the porous shroud alters vortex shedding by introducing new separation points, widening the wake, and shifting the dominant Strouhal number to lower values. The numerical model reproduces these effects with good accuracy, confirming the suitability of the homogenized approach for capturing porosity-induced modifications. Aeroelastic tests reveal that the porous façade can suppress VIV initiation by disrupting force coherence during the first oscillation cycles, while external perturbations restore synchronization and lead to full VIV development. The results demonstrate that the mitigation effect of porosity is conditional and state-dependent, providing new insight into its potential as a VIV control strategy for civil structures.