Testing the Capabilities of Wind Tunnel Fans as large-scale velocity fluctuation generators

Wind tunnel testing requires an accurate representation of natural flows. In particular, large vorticose structures represent a challenge for the wind engineer. Classical passive turbulence generation techniques, such as grids and spire elements, show limitations in scale dimensions and turbulence quality. Conversely, active methods like moving grids, struggle to target very low frequencies of the spectrum and may incur high installation costs. A cost-effective and promising solution for injecting energy into the low-frequency spectrum is the active control of fans. In this paper, the authors propose a straightforward methodology for the characterization of the facility’s generators, highlighting possibilities and limitations of this solution.