JINA: Jet Installation Noise Abatement

众所周知，飞机噪音是造成许多生理和心理影响的原因。根据最近的研究，飞机噪音不仅影响舒适性、生活质量、生产力和学习，而且还增加了因中风、冠心病和心血管疾病而住院和死亡的风险。世界卫生组织在2011年估计，在西欧国家，由于暴露在高水平的噪音中，每年损失的健康寿命年多达160万年。政府和机场运营商也承认，噪音限制了航空公司机队的增长和运营，对英国经济产生了直接影响。根据欧洲控制组织的预测，欧洲的空中交通预计将继续其长期增长趋势，从2010年到2030年，航班数量将增加2.2倍，相关的环境滋扰，特别是噪音可能会增加。因此，现在已经制定了越来越严格的环境法规，以减少飞机噪音的影响。因此，对于空中客车和巴西航空工业公司等主要航空工业来说，更好地了解空气动力噪声的产生机理，开发更稳健和有效的方法从源头上降低噪声具有重要意义。高旁通比涡扇的引入在显著改善喷气发动机气动性能的同时，也带来了一种气动声学挑战，即由于射流流体动力场与高升力装置部件的相互作用而产生的“射流安装效应”。射流的线性或非线性流体动力场与高升程装置部件的相互作用导致低频噪声显著增加，并可能出现一些非谐音。虽然最近的一些研究为简单圆形射流情况下低频噪声放大的物理机制提供了一些见解，但我们目前对射流流体动力场、流动不稳定性和捕获的声学模式之间的相互作用的了解仍然非常有限，特别是对于产生噪声的非常规射流。在济南，我们的方法是通过优化喷嘴形状来操纵射流流体动力场来降低低频噪声放大。JINA活动将汇集实验和计算空气声学以及设计优化方面的专业知识，以及一个强大的国际咨询和工业委员会，旨在发展对喷气式飞机安装噪声的基本理解，导致设计和制造下一代安静的喷气式发动机。

Aircraft noise is known to be responsible for many physiological and psychological effects. According to the recent studies, aircraft noise not only creates a nuisance by affecting amenity, quality of life, productivity, and learning, but it also increases the risk of hospital admissions and mortality due to strokes, coronary heart disease, and cardiovascular disease. The World Health Organization estimated in 2011 that up to 1.6 million healthy life years are lost annually in the western European countries because of exposure to high levels of noise. The noise is also acknowledged by governments and airport operators as a limit to both airline fleet growth and their operations, with direct consequences to the UK economy. Based on the EUROCONTROL forecasts, the air traffic in Europe is expected to continue its long-term growth trend and the number of flights will increase by up to 2.2 times from 2010 to 2030, with the potential increase in related environmental nuisances, particularly noise. As a result, ever more stringent environmental regulations are now in place to reduce the impact of aircraft noise. It is, therefore, of great importance for major aviation industries, such as Airbus and Embraer, to better understand the aerodynamic noise generation mechanisms and develop more robust and effective methods to reduce the noise at source. While the introduction of high bypass ratio turbofans led to significant improvement of the aerodynamic performance of jet engines, it also brought about an aeroacoustical challenge, known as the "jet installation effect", due to the interaction of the jet hydrodynamic field with the high lift device components. The interaction of the jet linear or non-linear hydrodynamic field with the high-lift device components results in a significant increase of noise at low frequencies and also the potential emergence of some aharmonic tones. While a number of very recent studies have provided some insights into the physics of the low-frequency noise amplification in the case of simple circular jets, our current understanding of the interplay between the jet hydrodynamic field, the flow instabilities and the trapped acoustic modes, particularly for non-conventional jets, which generates noise, remains very limited. Our approach in JINA is to reduce the low-frequency noise amplification by the manipulation of the jet hydrodynamic field via nozzle shape optimization. The JINA campaign will bring together expertise in experimental and computational aeroacoustics and design optimization, alongside a strong international advisory and industrial board, aiming at the development of fundamental understanding of jet installation noise, leading to design and manufacture of next-generation quiet jet engines.