Partially resolved numerical simulation of flow-induced aircraft noise

流致飞机噪声的部分解析数值模拟

• 批准号: 203459-2006
• 负责人: Lien, FueSang
• 金额: $ 2.11万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2006
• 资助国家: 加拿大
• 起止时间: 2006-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=334001
• 关键词: Partially; resolved; numerical; simulation; flow

This proposal is motivated by the fact that the largest ever European aircraft noise research project, known as SILENCE(R), was launched in April 2001. A consortium of 51 companies have collaborated for 4 years to validate new technologies for reducing aircraft noise by up to 6 decibels (dB) as of 2008. The total budget exceeds 110 million Euros.    Aircraft noise, categorized by airframe and jet noise, has become an increasingly important factor in aircraft design due to its environmental impact on the areas surrounding airports. At takeoff, when the engine is operating at full thrust, the main source of noise is the jet. Although jet noise can be reduced by choosing a turbofan engine with a high bypass ratio, in practice, the maximum bypass ratio is still limited by physical factors such as the length of the fan blade. An alternative approach is to introduce chevrons and tabs in a nozzle to enhance mixing between core, fan and ambient air streams at the expense of engine efficiency.    It is believed that a better understanding of the source mechanism, in which turbulence plays a very important role, will facilitate the generation of new noise-reducing concepts. It is against the above background that a research program is put forward in which both airframe and jet noise will be investigated by adopting a hybrid approach, in which the instantaneous near-field flow solutions will first be obtained with Partially Resolved Numerical Simulation.  The far-field sound can then be calculated using a separate integral method (e.g., the Ffowcs Williams and Hawkings method or the Kirchhoff method) using the source terms obtained from the previous near-field flow solutions.

这项建议的动机是，欧洲有史以来最大的飞机噪音研究项目，称为SILENCE（R），于2001年4月启动。一个由51家公司组成的联盟已经合作了4年，以验证截至2008年将飞机噪音降低6分贝（dB）的新技术。总预算超过1.1亿欧元。 飞机噪声，分为机身噪声和喷气噪声，由于其对机场周围区域的环境影响，已成为飞机设计中越来越重要的因素。在起飞时，当发动机以全推力运行时，噪音的主要来源是喷气。虽然通过选择高涵道比的涡扇发动机可以降低喷气噪声，但在实际应用中，最大涵道比仍然受到风扇叶片长度等物理因素的限制。另一种方法是在喷嘴中引入人字形和突片，以牺牲发动机效率来增强核心、风扇和环境空气流之间的混合。 人们相信，更好地理解湍流在其中起着非常重要作用的源机制，将有助于产生新的降噪概念。正是在上述背景下，本文提出了一个研究方案，采用混合方法研究机身和喷气噪声，首先通过部分解析数值模拟获得瞬时近场流场解，然后使用分离积分方法计算远场声音（例如，Ffowcs威廉姆斯和霍金斯方法或基尔霍夫方法），使用从以前的近场流解获得的源项。