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 geome...

Because of the high noise levels radiated by military jet aircraft, it has been hypothesized that nonlinearity influences the propagation of the noise. A numerical model, which accounts for second-order cumulative nonlinearity, atmospheric absorption and dispersion, and geometrical spreading, has been developed to propagate jet noise waveforms. Numerical propagation of recorded waveforms from r...

Beamforming techniques for aeroacoustics applications have undergone significant advances over the past decade to account for difficulties that arise when traditional methods are applied to distributed sources such as those found in jet noise. Nevertheless, successful source reconstructions depend on array geometry and the assumed source model. The application of phased-array algorithms to grou...

It is desirable to isolate independent noise sources in jets for targeted noise reduction methodologies. The application of traditional partial field decomposition (PFD) techniques to jet noise fields is useful for estimating the number of incoherent (equivalent) noise sources within a jet and for implementing near-field acoustical holography, but it does not generally provide physically meanin...

The features of the data acquisition and control systems of the NASA Langley Research Cen-ter's Jet Noise Laboratory are presented. The Jet Noise Laboratory is a facility that simulates realistic mixed ow turbofan jet engine nozzle exhaust systems in simulated ight. The system is capable of acquiring data for a complete take-oo assessment of noise and nozzle performance. This paper describes th...