Flap Noise

预计到2020年，世界航空运输需求将增加一倍，因此降低每架飞机的噪音水平的任务变得极为紧迫。在过去的20年里，由于采用了先进的风扇设计和使用了具有超高涵道比的喷气发动机，仅在降低飞机噪音方面就取得了重大的技术进步。由于这些进步，机体噪声和由发动机安装效应引起的非传统噪声源正在成为飞机噪声总体降低的主要限制因素。反过来，襟翼噪声是进场条件下机体噪声的一个非常重要的组成部分，正如最近的一项试验研究所表明的，襟翼与喷流的相互作用也会在起飞条件下产生非常显著的噪声。这使得许多传统飞机的生存能力，特别是那些发动机在机翼下的配置，处于危险之中。与此同时，正如国际航空声学界所承认的那样，对襟翼噪声的机理仍然知之甚少。在新的项目中，我们将开发一种新的物理洞察力的方法来理解和预测宽带和音调襟翼噪声。在这项工作中，我们将联合收割机和扩展的两个模型的框架内开发的两个成功的EPSRC资助的航空声学项目成为一个新的统一的噪声预测方案。该方案将捕获增升装置（如襟翼和襟副翼）的音调和宽带噪声分量以及它们与湍流射流的相互作用。新模型将在计算流体动力学（CFD）工具预测的声源与使用混合数学建模工具的远场传播之间进行精确匹配。利用新模型，我们将系统地研究襟翼噪声的机理，并调查控制装置，如多孔襟翼边缘表面和安装在襟翼后缘的涡流发生器，对噪声的影响。该项目是先进的数值模拟，高性能计算和最先进的声学分析方法的良好平衡的结合。所有研究人员都是各自领域的专家--航空声学、空气动力学、湍流建模和数值方法。因此，该项目的优势在于其多学科和协作的性质，确保了协同作用和思想和方法的交叉融合。计划中的工作具有很大的环境重要性，旨在直接改善机场附近人民的生活质量。它还具有商业重要性，可能会保护英国在高科技领域的就业机会，其结果将对空中客车和劳斯莱斯等英国领先的航空航天业感兴趣。这是因为将为声学设计创造更大的物理理解和有价值的预测技术。这些最终将导致更环保，因此具有商业竞争力的飞机，可以更快地以更低的成本推向市场。这项研究将通过在高影响力期刊上发表文章和在重要国际会议上发表演讲的方式传播。该项目的国际合作背景增强了潜在的传播途径。还将通过其他专家会议，如皇家学会会议，传播项目成果。此外，还将安排一系列研讨会，在欧洲主要航空声学中心进一步传播项目成果。该项目的国际合作背景将加强潜在的传播途径。预计该项目产生的新的训练有素的计算流体动力学家/空气动力学家/空气声学家将在其今后的工作中传播项目后的成果。

With the projected demand for air transport set to double the world aircraft fleet by 2020, the task of reducing noise levels of each individual aircraft is becoming extremely urgent. Significant technological advances in the reduction of turbomachinery noise alone has been achieved over the last 20 years due to the implementation of advanced fan designs and the use of jet engines with ultra high bypass ratios. Because of these advances, airframe noise and non-traditional noise sources due to the engine installation effects are becoming a major limiting factor in the overall reduction of the aircraft noise. In turn, flap noise is a very important component of airframe noise for approach conditions and, as a recent experimental study demonstrated, the flap interaction with the jet can also produce very significant noise for take-off conditions. This puts the viability of many conventional aircraft, especially those with the engine-under-the-wing configuration, in jeopardy. At the same time, as recognised by the international aeroacoustic community, the mechanisms of flap noise still remain very poorly understood. In the new project, we will develop a new physically insightful method for understanding and predicting both broadband and tonal flap noise. In this work we will combine and extend the two models developed in the framework of two previous successful EPSRC-funded aeroacoustic projects into a new unified noise prediction scheme. This scheme will capture both the tonal and broadband noise components of the high-lift devices, such as wing flaps and flaperons and their interaction with the turbulent jet. The new model will have an exact match between the sound sources predicted by Computational Fluid Dynamics (CFD) tools and far-field propagation using a mixture of mathematical modelling tools. Using the new model we will systematically study the mechanisms of flap noise and investigate the effect of control devices, such as porous flap edge surfaces and vortex generators installed on the flap trailing edge, on noise.This Project is a well-balanced combination of advanced numerical modelling, high performance computing and state-of-the art acoustic analysis methods. All investigators are experts in their fields - aeroacoustics, aerodynamics, turbulence modelling and numerical methods. Thus a strong side of the Project is its multi-disciplinary and collaborative nature that ensures synergy and cross-fertilisation of ideas and methods.The planned work has great environmental importance, aimed directly at improving the quality of people's lives in the vicinity of airports. It also has commercial importance, potentially safeguarding UK jobs in a high technology area, and its results will be of interest for the leading UK airspace industry such as Airbus and Rolls-Royce plc. This is because greater physical understanding and valuable predictive technology for acoustics design will be created. These should ultimately result in more environmentally friendly, and hence commercially competitive, aircraft that can be brought to the market more quickly and at lower cost. The research will be disseminated via publications in high-impact journals and presentations at key international conferences. The international collaborative context of this project enhances the potential dissemination paths. The projects results will be also disseminated through other specialist meetings, such as at Royal Society Meetings. In addition, a series of seminar talks will be arranged for to further disseminate the projects results in leading European aeroacoustics centres. The international collaborative context of this project will enhance the potential dissemination paths. It is also expected that the new highly trained computational fluid dynamicist/aerodynamicist/aeroacoustician produced in the project will be disseminating the post-project results in her/his further work.