Noise Source Localization in Closed Test Sections with Microphone Arrays

In order to meet the objectives of ACARE Vision 2020 which aims amongst others at a reduction in perceived noise to one half of current average levels aero-acoustic testing methods must improve considerably. With the advent of the phased array microphone technologies and advanced data processing several research groups have developed the capability to perform acoustic tests within closed-test-section wind tunnels. This paper gives an overview of the current state of the art in microphone array techniques at various European research establishments. Based on these results future developments driven by the industrial requirements will be outlined. The main objective in this context is the extrapolation of results obtained from wind tunnel measurement to real flight conditions