The design, characterization, and performance assessment of an aeroacoustic measurement system for a hard-walled wind tunnel

Abstract

A new aeroacoustic measurement system for the large wind tunnel (LWT) at the University of New South Wales (UNSW) has been designed and characterized. The LWT is a closed-return type wind tunnel with a 2.87m × 1.28 m × 0.92 m hard-walled test-section, which contains 0.61m × 0.61 m access windows one of which was used to attach a 1.06m × 0.61 m × 0.61 m anechoic chamber lined with 100 mm thick Basotect foam. A 16-microphone spiral phased array embedded in the chamber was used to characterize the acoustical properties of the chamber and localize several acoustic and aeroacoustic sources placed in the reverberant test-section. Acoustic sources considered include single and dual speaker setup, while a UAV propeller and a forward-backward step mounted on the test-section sidewall were used as an aeroacoustic source. The beamforming output in each case was deconvolved using several existing algorithms to assess their performance under reflective boundary conditions. Additionally, a numerical tailored Greens function approach to beamforming is being considered to exclude the effects of reverberations within the test-section from the array output. It is expected that the present work will help develop strategies and guidelines for aero/hydroacoustic testing under reverberant conditions.