Авиация и космонавтика
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Contents1 The Noise Problem2 Effects of Noise
Hearing Loss
Noise Interference
Sleep Disturbance
Noise Influence on Health3 Noise Sources
Jet Noise
Turbomachinery Noise4 Noise Measurement and Rules
Noise Effectiveness Forecast (NEF)
Effective Perceived Noise Level (EPNL)
5 Noise Certification
Noise limits6 Calculations
Tupolev 154M Description
Noise calculations
Take-off Noise Calculation
Landing Approach Noise Claculation7 Noise Suppression
Jet Noise Suppression
Duct Linings
Duct Lining Calculation1 The Noise Problem
Though long of concern to neighbors of major airports, aircraft noise first became a major problem with the introduction of turbojet-powered commercial aircraft (Tupolev 104, Boeing 707, Dehavilland Comet) in the late 1950s. It was recognized at the time that the noise levels produced by turbojet powered aircraft would be unacceptable to persons living under the take-off pattern of major airports. Accordingly, much effort was devoted to developing jet noise suppressors, with some modest success. Take-off noise restrictions were imposed by some airport managements, and nearly all first-generation turbojet-powered transports were equipped with jet noise suppressors at a significant cost in weight, thrust, and fuel consumption.
The introduction of the turbofan engine, with its lower jet velocity, temporarily alleviated the jet noise problem but increased the high-frequency turbomachinery noise, which became a severe problem on landing approach as well as on take-off. This noise was reduced somewhat by choosing proper rotor and stator blade numbers and spacing and by using engines of the single-mixed-jet type.
2 Effects

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