Measurement and Prediction of Noise Propagation from a High-Power Jet Aircraft

Bicoherence analysis of model-scale jet noise

“…However, the strongest evidence of the relevance of nonlinearity in high-amplitude jet noise propagation has come from work that involved field measurements of the noise radiated by the F-22 Raptor. 9,10 In these studies, a nonlinear propagation model predicted significant waveform steepening and a spectral energy transfer to high frequencies that agreed closely with measured data. With one aircraft engine at afterburner power, nonlinear propagation out to 305 m results in levels at 20 kHz that are approximately 100 dB greater than predicted by linear propagation.…”

“…In other words, the relative measurement bandwidth cannot currently be scaled to be the same as for a full-scale test. As an example, if we were to scale the F-22 geometric conditions and analysis bandwidth 9,10 to those of the model-scale experiment described in this Letter, we would need an anechoic chamber that allowed over 17 m of far-field propagation and microphones with a response exceeding 2 MHz.…”

Near-field shock formation in noise propagation from a high-power jet aircraft

“…Early studies 1,2 of nonlinear propagation effects in noise radiated from full-scale supersonic jet engines have been extended recently [3][4][5][6][7][8][9] and include a far-field analysis of F-35A static run-up data. 10 Comparison of the measurements in Ref.…”

Prediction of nonlinear propagation of noise from a solid rocket motor

“…This is likely a limitation because the noise propagation from military and other highpower aircraft has been shown to be appreciably nonlinear, despite significantly lower thrust. [4][5][6] For example, the average vacuum thrust produced by a four-segment reusable solid rocket motor from the Space Shuttle is 13 MN,7 approximately 70 times the maximum thrust from the F-35 Joint Strike Fighter, which has been the subject of two recent nonlinear propagation studies. 8,9 Shepherd et al 10 further showed that the high-amplitude noise radiated from a spherical source at rocket-like levels undergoes significant changes at the high and low ends of the spectrum as it propagates.…”

“…Nonlinear F/A-18E noise propagation was calculated by Gee et al, 18 Brouwer, 19 and Saxena et al 20 using different GBE-based algorithms. A more comprehensive treatment of the noise radiated by the F-22A Raptor was carried out by Gee et al 4,5 and algorithm refinements were incorporated in a study of the noise propagation from the F-35AA Joint Strike Fighter. 8 In these latter studies of F-22A and F-35AA noise, excellent agreement between nonlinear models and measurements were achieved at a maximum comparison distance of 305 m (1000 ft).…”