大型客机起飞着陆过程噪声辐射特性对比分析

 基于准稳态假设和分布点声源模型，并采用最新发展的噪声源半经验参数预测公式，发展和完善了用于飞机飞行过程中噪声辐射预测的计算模型和方法。该计算方法能够预测飞机起飞、着陆过程中的适航噪声，并能够对飞机不同噪声源的噪声辐射特性（声级、频谱特性和指向性等）进行计算分析。以某大型客机为对象，对飞机进场着陆过程和起飞过程中飞机噪声源进行了计算分析，计算结果表明，飞机进场着陆和起飞过程中，不同噪声源对远场噪声级的影响有明显的差异，起飞过程中发动机风扇噪声源是最主要的噪声辐射源，而在进场着陆过程中飞机机体噪声（包括起落架和襟翼等）是重要的飞机噪声源。文中也给出了不同噪声源频谱特性和指向特性等。

Noise Radiation of Large-scale Commercial Aircraft in Take-off and Landing

Based on the assumption of quasi-steady model,and with the using of the new developed semi-empirical prediction formula for aircraft noise source,an improved model and a method to predict the flyover noise of the large-scale commercial aircraft with turbofan engine are developed in this paper.The centralized point source model is changed to the distributed point source model in the prediction procedure.The new semi-empirical prediction formula of the fan noise and jet noise are used to suit for the advanced ultra-high bypass(UHB) engines.This improved prediction method and code can be used in the system optimization and assessment study of modern large-scale commercial aircraft,and be used to predict the spectrum and directivity for each source on aircraft.The noise radiation from a large wide-body commercial aircraft with two aisles and four turbofans in take-off and landing is computed and analyzed.It is shown that the influence of engine noise source is different from that of airframe noise source in both take-off and landing.The engine noise radiation is the main noise source in take-off,but the airframe noise radiation is the main noise source in landing.The spectra and directivities of aircraft noise for each source are also predicted and analyzed.