The physical properties and subjective characteristics of sound and several special methods of measuring sound levels are discussed in order to provide a basic understanding of sound in general and noise in particular. The Federal Aviation Administration's regulation, FAR36, which stipulates the allowable perceived noise levels produced by commercial jet aircraft, is examined in detail. The principle of jet propulsion, the basic components of turbojet and turbofan engines, the theory of aerodynamic sound and the origin of the perceived noise decibel (which is the basic unit for measuring aircraft noise) are presented to provide an understanding of the fundamentals of jet aircraft noise. The origin of the jet noise problem is traced to the introduction of commercial jet aircraft in 1958. The sources of jet engine noise, their generating mechanisms and the applications of acoustic design technology incorporated to reduce the various components of jet engine noise are identified for each generation of jet engines powering subsonic commercial jet aircraft: turbojet, low bypass ratio turbofan and high bypass ratio turbofan engines. The technique used to identify a source of jet engine noise, specifically compressor noise, is demonstrated by presenting the spectral analysis (obtained by utilizing Fast Fourier Transform Software) of noise produced by a single stage axial flow fan rig. A review of airport noise, due to jet aircraft approaches and takeoffs, throughout the history of commercial jet aircraft, demonstrates the progress the aircraft industry has made in reducing the noise produced by jet engines powering commercial jet aircraft.
| Identifer | oai:union.ndltd.org:ucf.edu/oai:stars.library.ucf.edu:rtd-1396 |
| Date | 01 July 1979 |
| Creators | Beck, Bradley D. |
| Publisher | University of Central Florida |
| Source Sets | University of Central Florida |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Retrospective Theses and Dissertations |
| Rights | Public Domain |
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