Understanding the causes of noise emanating from the inter-wheel region of two-wheel landing gears and their mitigation

飞机起落架是巨大的钝体附属物，产生高度复杂和不稳定的流动，表现为噪音。飞机噪音不仅会对机场附近的居民造成严重干扰，还会对人们的健康产生负面影响。为了限制噪音排放，航空当局制定了严格的法规，向航空公司征收与噪音有关的费用，为飞机运营商提供财政激励，以努力减少噪音排放。因此，了解噪音的来源，并在可能的情况下减轻噪音，符合各方的利益。

Aircraft landing gears are large, bluff bodied appendages that create highly complex and unsteady flow, manifesting itself as noise. Aircraft noise not only causes significant disturbance to those that live near airports, it has also been associated with negative impacts on people's health. In an effort to restrict noise emissions, aviation authorities placed stringent regulations that impose noise related fees on airlines, providing a financial incentive for aircraft operators to try and reduce their noise emission. It is therefore in the interest of many diverse parties to understand the sources of noise generation and mitigate them wherever possible. The inter-wheel region of two-wheel landing gears has been identified as a potentially key source of noise generation. In particular, a severe flow behaviour dominated by strong cross-stream fluid ejections has been observed to occur in this region. The proposed research aims to identify the underlying physical mechanisms behind these ejections and how parametric changes to the landing gear geometry may affect both the cross-stream ejections and the resultant noise. Through the advancement of knowledge in this area, Messier-Bugatti-Dowty (the industrial partner) will be able to adapt their landing gear designs in a manner that will have the greatest potential to realize noise reductions. These benefits will improve the health and well being of the general populace that are currently impacted by aircraft noise, and increase the competitiveness of Messier-Bugatti-Dowty.