Flap Noise

预计到2020年，全球飞机机队对航空运输的需求将增加一倍，降低每架飞机的噪音水平的任务变得极其紧迫。在过去的20年里，由于先进风扇设计的实施和超高涵道比喷气发动机的使用，仅在降低涡轮机械噪音方面就取得了重大的技术进步。由于这些进步，机身噪音和由发动机安装效应引起的非传统噪声源正在成为降低飞机噪音的主要限制因素。在进近条件下，襟翼噪声是机体噪声的一个重要组成部分，最近的一项实验研究表明，襟翼与喷气机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处于危险之中，尤其是那些发动机在机翼下的飞机。与此同时，正如国际航空声学界所认识到的那样，襟翼噪声的机制仍然知之甚少。在新项目中，我们将开发一种新的物理上有洞察力的方法来理解和预测宽带和音调瓣噪声。在这项工作中，我们将结合并扩展在前两个成功的epsrc资助的航空声学项目框架内开发的两个模型，使其成为一个新的统一的噪声预测方案。该方案将捕获高升力装置的音调和宽带噪声成分，如机翼襟翼和襟副翼及其与湍流射流的相互作用。新模型将在计算流体动力学（CFD）工具预测的声源和使用混合数学建模工具的远场传播之间进行精确匹配。利用该模型，我们将系统地研究襟翼噪声的产生机理，并研究控制装置（如多孔襟翼边缘表面和安装在襟翼尾缘的涡发生器）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完美结合。所有研究人员都是各自领域的专家——空气声学、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性，确保了思想和方法的协同和交叉融合。计划中的工作具有重大的环境重要性，其直接目的是提高机场附近人们的生活质量。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，其结果将引起英国领先的航空工业的兴趣，如空中客车公司和劳斯莱斯公司。这是因为将为声学设计创造更好的物理理解和有价值的预测技术。这将最终导致更环保，从而具有商业竞争力的飞机，可以更快地以更低的成本投入市场。这项研究将通过高影响力期刊的出版物和在重要国际会议上的发言来传播。这个项目的国际合作背景加强了潜在的传播途径。项目结果也将通过其他专家会议，如皇家学会会议进行传播。此外，将安排一系列研讨会，在欧洲主要的空气声学中心进一步传播项目成果。这个项目的国际合作背景将加强潜在的传播途径。项目中培养的新的训练有素的计算流体动力学家/空气动力学家/空气声学家预计将在她/他的进一步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.