Low Noise ATRA - Phased Array Measurements of Jet Noise in Flight

Abstract

DLR performed flight tests with retro-fit modifications for noise reduction on its Airbus A320 research aircraft ATRA. Phased array measurements were performed in 2016 with the baseline aircraft and in 2019 with the noise modified aircraft. The array data were processed with acoustic source localisation methods based on the deconvoluton of beamforming maps for moving sources. The resulting sound source maps show the distribution of the sound sources on the aircraft for three emission angles, in the forward arc, overhead, and in the rear arc. Frequency spectra for individual source regions like the engine inlet, the nozzle, and the jet are averaged over all fly-overs in the same configuration for the baseline and the modified aircraft. The comparison of the baseline with the modified aircraft data for the engine nozzle and jet regions confirms that the modified nozzle reduces jet noise.