Near-field noise measurements of a high-performance military jet aircraft

Published near-field analyses of full-scale jet noise are limited, and the application of observed laboratory-scale phenomena to full-scale jets is not well understood. To obtain a greater understanding of the connection between radiated noise and source characteristics in full-scale, heated, supersonic jets produced by military aircraft, extensive acoustical measurements were made in the geometric near field of the jet produced by the installed engine on an F-22A Raptor. In this paper, the experimental setup is described in detail. Level-based results are shown, including overall levels, spectral content and how the spectra vary over space. In addition, basic time waveform analyses are performed. From these results, important near-field jet-noise phenomena are identified, and several technical and logistical issues in implementing near-field measurements of full-scale jets are addressed. © 2012 Institute of Noise Control Engineering.