Design process to evaluate potential of wind noise at facade elements

Wind noise generation from a solar shading façade is a design concern of engineers. A shading façade consists typically of a series of fins which repeat sequentially and that is mounted at a certain distance from the building surface, forming with it the sides of a duct where the wind can pass through. The flow instability created by the vortex detachment from the fins can excite the acoustic mode of the duct and instigate a phenomenon of aero-acoustic resonance which manifests with the generation of tonal noise. No design tools are currently available to assess the likelihood of tonal noise to occur in similar façade. Existing guidance notes have been used by Arup Acoustics for the last 20 years and have never been fully tested in the built environment to confirm their validity. A numerical methodology is presented here which aims to predict, through the CFD modelling of the aero-acoustic resonant system, if the coupling of ducted flow and vortex shedding around the fins element of a façade could lead to tonal noise generation.