Aircraft Noise: Noise Sources

Abstract

Overview The subject of aircraft noise is too vast to be covered in a single chapter; thus, we focus on those issues that are required for a low-order simulation of aircraft noise emission and propagation. The chapter is organised as follows: We first discuss the importance of the subject (§ 16.1) and introduce basic definitions that are used to characterise aircraft noise (§ 16.2). We then establish the framework for the development of an aircraft-noise program that is synchronised with the flight mechanics (§ 16.3). The sources of noise are split into propulsive (§ 16.4) and non-propulsive components (§ 16.6). We include a discussion of the APU noise as a separate item (§ 16.5). The propeller-noise model (§ 16.7) is discussed in isolation from airframe and engines. Chapter 17 deals with propagation effects. Chapter 18 deals with noise trajectories. KEY CONCEPTS : Sound, Noise Metrics, Engine Noise, Airframe Noise, Propeller Noise, APU Noise, Aircraft-Noise Model. Introduction In the beginning there was silence, or so the story goes. Then came human activities and jet engines. This is when the noise started to hurt. Low-flying aircraft cause nasty physiological effects and are bad for your well-being. To be fair, noise pollution is just one of many environmental issues that face the aviation industry; it is part of the larger context of local air quality, combustion emissions, environmental compatibility, policies and regulations and public health.