Title: Verification of Noise Forecast Capabilities for Application to Full-scale Supersonic-capable Jet Engine Development
Abstract: Jet noise theory has been developed and validated based on controlled laboratory scale measurements with considerable success. However, few full-scale jet engine noise studies have been conducted. The analytic methods of Tam and Viswanathan were applied to fullscale high-performance aircraft flight noise measurements. These measurements were recorded to produce reference spectra for the U.S. Department of Defense community noise prediction model. The aircraft noise measurement’s atmospheric conditions at the flight altitude were estimated using meteorological ground heating methods. Ambient conditions and engine speed were used to calculate jet noise parameters using substantiated engine thermodynamic cycle models. Fluid-dynamic measures of exhaust jet velocity, Vj, diameter, Dj, and temperature ratio, Tt/Ta, were used to determine variation of OverAll Sound Pressure Levels (OASPLs). Flight-measured noise data compare well to the relations developed by Viswanathan and Tam, but did not collapse as anticipated. Previous studies of jet noise propagation have shown that non-spherical spreading loss occurs in the measurements under study. Both non-spherical losses and scaling of OASPL to account for propagation range and jet diameter improve collapse. This favorable result substantially verifies the methodology of this study, leaving some concerns about scaling rules.
Publication Year: 2014
Publication Date: 2014-06-13
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 1
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