A Semi-empirical Model for Jet Noise Prediction in the Geometric Near Field

Bassetti, Alessandro; Fisher, Michael J.; Morfey, C. L.

doi:10.2514/6.2004-2831

Cited by 3 publications

(2 citation statements)

References 6 publications

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“…While the choice for θ in Eqn. (7) influences the selection of the other parameters associated with the correlated line array, for simplicity the far-field directivity angle of 125 is used based on previously measured afterburner data 28,33 . The correlated source produces highly directional noise and contributes significantly to the downstream radiation.…”

Section: Initial Application Of Modelmentioning

confidence: 99%

Simple-source model of military jet aircraft noise

Morgan¹,

Neilsen²,

Gee³

et al. 2012

noise cont engng j

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This paper describes a method for determining a semi-empirical, equivalent simple-source model that accounts for the sound radiation in the vicinity of a high-performance military aircraft. The characteristics of the equivalent source are guided by previously reported observations of jet noise, namely that the strengths of the partially correlated sources are distributed asymmetrically. The parameters of the equivalent source model are chosen to reproduce the data recorded on large planar apertures in the near-field of an F-22 Raptor. First, the location of the dominant source region for a given frequency is found by matching the orientation of the interference nulls in a sound pressure level map. Second, the relative contributions of the correlated and uncorrelated portions of the equivalent source are chosen to replicate the directionality and extent of the sound field. The source characteristics are selected based on the data at one measurement plane but are able to approximate the radiation at other nearand mid-field locations. The method is used to find equivalent sources at several frequencies and different engine conditions.

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Section: Initial Application Of Modelmentioning

confidence: 99%

Simple-source model of military jet aircraft noise

Morgan¹,

Neilsen²,

Gee³

et al. 2012

noise cont engng j

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show abstract

“…Although researchers have investigated and determined features of jet turbulence in laboratory experiments, 1,2 properties of heated, supersonic jets from military aircraft cannot be directly measured. Computational models, both analytical 3,4 and empirical, 5,6 give important insights into the physics behind jet noise radiation. The equivalent source model (ESM) developed in this paper is somewhat similar to acoustical holography, 7 in that it starts with measured data and then uses a mathematical model to predict the sound field at other locations.…”

Section: Introductionmentioning

confidence: 99%

A Bayesian based equivalent sound source model for a military jet aircraft

Hart

Neilsen

Gee

et al. 2013

The Journal of the Acoustical Society of America

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The two-source model for jet noise holds that turbulent mixing noise in jets is generated by uncorrelated, fine-scale (FSS) and partially correlated, large-scale (LSS) turbulent structures [Tam et al., J. Fluid Mech. 615, 253-292, (2008)]. The noise from an F-22A Raptor is modeled with an equivalent source consisting of two line arrays of monopole sources. These arrays, one correlated and one uncorrelated, with Rayleigh distributed amplitudes, account for both FSS and LSS sound propagation [J. Morgan, J. Acoust. Soc. Am. 129, 2442 (2011)]. The equivalent source parameters are selected based on Bayesian methods implemented with simulated annealing and fast Gibbs sampler algorithms. This method yields the best fit parameters, and the sensitivity of the solution is indicated by the generated posterior probability distributions. Analysis of the resulting equivalent sources shows that the directional, correlated line array has greater effect on the near field sound, and the sensitivity of the array's parameters increases as the frequency increases. This equivalent source model can generate results up to 2500 Hz and accurately predict both near field and far field measurements. The analysis suggests that the shape of the source distribution changes as the frequency increases.

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Semi Empirical Jet Noise Modelling for Cabin Noise Predictions -- Acoustic Loads in the Geometric Near Field

Bassetti

Guérin

2011

17th AIAA/CEAS Aeroacoustics Conference (32nd AIAA Aeroacoustics Conference)

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A Semi-empirical Model for Jet Noise Prediction in the Geometric Near Field

Cited by 3 publications

References 6 publications

Simple-source model of military jet aircraft noise

Simple-source model of military jet aircraft noise

A Bayesian based equivalent sound source model for a military jet aircraft

Semi Empirical Jet Noise Modelling for Cabin Noise Predictions -- Acoustic Loads in the Geometric Near Field

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