This report presents a review and analysis of recent aircraft flyover data where the aircraft is at a low angle of elevation relative to the observer. Excess attenuation factors (attenuation in addition to normal spherical divergence and atmospheric absorption losses), evaluated for a range of aircraft types, were found to vary between aircraft and could be generally characterized as a function of aircraft angle of elevation only. Fuselage sheidling or installation effects could not be positively identified although their presence is suggested by the differing excess attenuation characteristics of each aircraft type. Lack of detail in the data available for review precluded the identification of any propagation losses due to turbulent scattering of sound in the atmosphere. The results of the study suggest that currently applied predictive models for sideline noise tend to overestimate noise levels - particularly for 3 and 4 engine aircraft. An alternative approach to sideline noise prediction is suggested and recommendations are made to encourage technical development in this uncertain area of aircraft noise prediction. (Author)
Aircraft Sideline Noise: A Technical Review and Analysis of Contemporary Data
1977
47 pages
Report
Keine Angabe
Englisch
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