Grid Generated Turbulence for Aeroacoustic Facility

A preliminary version of this paper was presented at the AIAA Aviation 2020 forum (Paper 2020-2525).This provides an insight into grid generated turbulence for aeroacoustic studies. Several passive grids square bars were tested in open-jet facility University Bristol. The geometric properties and their position within tunnel contraction nozzle varied to quantify influence on average statistical flow as well self-noise. Moreover, case studies involving interaction noise generation with a NACA0012 airfoil cylinder conducted. Turbulence intensity, integral length scale, anisotropy by each characterized hot-wire measurements, associated far-field measured microphone array. results show that downstream evolution intensity scale comparable closed test-section wind-tunnel first hydraulic diameter exit. However, beyond diameter, plateaus scales rapid growth. positioned closest exit produced isotropy high levels but spectra suffered from contamination located farthest performed best terms could generate almost same level