Measurement of detailed flow statistics for trailing-edge noise prediction and mitigation

翼型噪声是任何有壁噪声源的典型航空声学问题，其源自任何运输系统或任何通风和发电系统。例如，它直接有助于预测和控制低速和高速风扇噪声以及由高升力装置或尾翼产生的机身噪声。因此，翼型噪声响应与增加的空中交通、自动驾驶车辆的扩散和嘈杂的工作条件相关的重要的当前和未来的环境和健康问题。在连续三届工业主席的框架内，舍布鲁克大学（UdeS）的航空声学研究小组在翼型噪声方面积累了丰富的专业知识，为最先进的数值模拟做出了贡献，这些数值模拟揭示了几种新的噪声机制，并指导了几种快速分析模型的开发。后者可以在任何旋转机械的预设计阶段使用，现在集成在一个正在商业化的完整的独特软件平台中。然而，任何这种虚拟开发都需要详细的实验验证，这可以在加拿大独特的测试设施UdeS的航空声学风洞中实现。这种验证过程不仅涉及麦克风阵列的声学测量，以提供对噪声源方向性和实际源定位的了解，而且还涉及从远程麦克风探头的压力测量到多线探头的局部热线风速测量以及粒子图像测速（PIV）的全局场风速测量的几种流量测量。后者已被证明可以提供有关翼型后缘周围三维紊流速度场的有价值的信息，因此也提供了有关噪声源的信息。本提案旨在通过为研究小组提供更强大的激光器和升级的后处理PIV软件来保持和扩展这种能力，这应该能够使UdeS的实验航空声学小组赶上该小组已经实现的模拟数量。它还应该允许该小组将相同的技术应用于更大的视野和更复杂的实验设置，例如在并行的超高效率和静音风扇联盟以及电动汽车内电气冷却和空调模块的合作研究项目中研究的复杂和完整的供暖，通风和空调模块。这将提供前所未有的数据库和有价值的信息，为此类系统提供更安静的解决方案。

Airfoil noise is the canonical aeroacoustic problem for any wall-bounded noise sources, stemming from any transportation system, or any ventilation and power generation systems. For instance, it directly contributes to the prediction and control of low and high speed fan noise and of airframe noise generated by high lift devices or empennages. As such, airfoil noise responds to important present and future environmental and health issues related to increasing air traffic, proliferation of autonomous vehicles and noisy work conditions. Within the framework of three consecutive Industrial Chairs, the Aeroacoustic research group at Université de Sherbrooke (UdeS) has developed a solid expertise on airfoil noise contributing to state of the art numerical simulations that have unveiled several new noise mechanisms and guided the development of several fast analytical models. The latter can then be used at a pre-design stage of any rotating machine and are now integrated in a complete unique software platform that is being commercialized. Yet, any of this virtual development requires a detailed experimental validation that can be achieved in the aeroacoustic wind tunnel at UdeS, a unique test facility in Canada. Such a validation procedure not only involve acoustic measurements with arrays of microphones to provide insight on the noise source directivity and the actual source localization, but also several flow measurements ranging from pressure measurements with remote microphone probes to local hot-wire anemometry with multiple wire probes, and global field anemometry by Particle Image Velocimetry (PIV). The latter has been shown to provide valuable information on the three dimensional turbulent velocity field around the airfoil trailing edge, and therefore the associated noise sources. The present proposal is then meant to maintain and extend such a capability by providing the research group with a more robust laser and an upgraded postprocessing PIV software, which should able the experimental aeroacoustic group at UdeS to catch up with the number of simulations already achieved by the group. It should also allow the group to apply the same technique to larger fields of view and to more complicated experimental setups such as complex and complete heat, ventilation and air conditioning modules as studied in the parallel Consortium for Ultra HighEfficiency and Quiet Fans and in the Collaborative Research Project on electrical cooling and air conditioning modules within electrical vehicles. This will provide an unprecedented database and valuable information to yield quieter solutions for such systems.