Understanding the fluctuating flow around two-wheel landing gear systems and innovative solutions for noise mitigation

自商业航空诞生以来，噪声污染一直是飞机的负面副产品。几个 调查显示，长时间暴露在飞机噪音环境中与各种健康状况有直接关系。 有问题。由于公众对这一问题的强烈反应，噪音政策变得越来越周期性 多年来的严格要求，由于这种转变，今天，过去最嘈杂的飞机(以前设计的飞机 1978)不能再在商业航线上运营。飞机的逐步淘汰是由于 越来越严格的噪音政策意味着飞机的留值可能会以 如果它在被逐步淘汰之前没有太多的使用余地，那么它就会在生命中的某个时间点。在……里面 此外，根据飞机的噪音排放，飞机经常被收取每次着陆的费用，在典型的一年中 运营多个航班对航空公司运营商来说可能是一笔巨大的成本。出于这些原因，航空公司正在 更倾向于购买更安静的飞机。这使所有大型飞机制造商都进入了一个 设计最安静的飞机的竞赛。到目前为止，飞机制造商在降噪方面的成功已经 主要是通过发动机技术的改进，今天取得的状态是这样的，在 在接近着陆时，起落架产生的噪音几乎与发动机产生的噪音相同。 起落架噪声主要是起落架周围产生的非恒定流结构和 它们与飞机部件的复杂相互作用。至此，起落架的基本机构 噪声的产生仍然没有得到很好的理解，因此很难制定有效的战略来 减轻对他们的压力。拟议的研究计划将确定噪音的可能原因和来源 通过发展对波动的、连贯的流动的全面理解来生成起落架 起落架的各种几何细节造成的结构。通过知识的进步， 在这一领域，预计将开发新的技术或方法来实现减少起落架 与目前的设计相比，噪音更大。该项目是与庞巴迪合作提出的。

Since the dawn of commercial aviation, noise pollution has been a negative by-product of aircraft. Several surveys have shown direct associations between extended exposure to aircraft noise and various health problems. As a result of strong public response to this issue, noise policies became periodically more and more stringent over the years, and owing to this shift, today, the noisiest aircraft from past (those designed before 1978) can no longer operate on commercial routes. The phasing out of aircraft as a consequence of the increasingly stringent noise policies implies that the retained value of an aircraft may dramatically reduce at a certain point in its life if it does not have much margin for use before being phased out of operation. In addition, based on their noise emission, aircraft are often charged fees per landing, which over a typical year of operation with numerous flights can be a significant cost to airline operators. For these reasons, airlines are more inclined towards purchasing quieter aircraft. This puts all the large aircraft manufacturers into a competition to design the quietest aircraft. So far, the success of aircraft manufacturers in noise reduction has been mostly through the improvements in engine technology and the state achieved today is such that, during approach to landing, the noise generated by landing gears is almost equal to that generated by the engines. Landing gear noise mainly results from the unsteady flow structures that are generated around landing gear and their complex interactions with the aircraft components. At this point, the basic mechanisms of landing gear noise generation are still not well understood and it is therefore difficult to develop efficient strategies to mitigate against them. The proposed research program will identify the possible causes and sources of noise generation for landing gears by developing a comprehensive understanding of the fluctuating, coherent flow structures attributable to various geometric details of landing gear. Through the advancement of knowledge in this area, it is expected that new techniques or methods will be developed to realize reductions in landing-gear noise compared to the present designs. This project is proposed in collaboration with Bombardier.