Vortex induced vibrations of rectangular cylinders arranged on a grid

A grid arrangement of hundred rectangular cylinders fixed to the facade of a house generates strong and disturbing mono-harmonic noise. The cross-flow vibration of the rectangular cylinders is identified as the origin of the noise. The present article proposes a complete investigation of the Vortex Induced Vibration (VIV) combined with a grid effect. It is based on in situ measurements, numerical (finite elements and Computational Fluid Dynamics (CFD)) and extensive wind tunnel modelling. A comparison between unsteady pressure tap measurements and CFD results allow to understand the vortex shedding process and synchronization type depending on the wind incidence and spacing of the cylinders. On the basis of this multi-approaches parametric investigation, a deep understanding of the VIV-grid phenomenon enables to propose two mitigation techniques. These techniques are tested and their effectiveness is reported in terms of vibration amplitude and acoustic intensity.