Aircraft noise modeling

Aircraft noise exerts an adverse influence on the environment and on people's health, and is also a performance issue. The aircraft noise problem is a complex topic that covers a number of areas, including passenger cabin and cockpit noise, ramp noise, structure-borne noise, propulsive system noise, jet noise, airframe noise, etc., each of which requires separate modeling and mitigation treatments. These noise sources can be studied by a variety of approaches, including analytical, experimental, simulation, and modeling. Nowadays, high-fidelity simulations, high-fidelity scale model tests, and flight tests play increasingly important roles in aircraft design and noise assessment. However, empirical, semiempirical, and physics-based modeling methods can still play an important role in assessment and optimization processes. These methods can be accurate, efficient, and cost-effective. Their reliability is often based on the theory of aerodynamic sound generation, scaling laws, and correlation with wind tunnel and flight tests. This chapter introduces several models that describe the noise generated by key aircraft components such as high-lift devices, landing gears, and rotors. Methods reviewed include semiempirical methods, component-based methods, physics-based methods, and analytical methods