Aerodynamic drag reduction, from science to control strategies in aerospace and sport

气动阻力是一种通过压力和剪切表现出来的损失形式。对于飞机来说，发动机产生推力以克服阻力。在像自行车这样的运动中，阻力限制了运动员能保持的速度。减少阻力可以直接节约能源或提高性能。这一点很重要，因为不可再生能源的消耗对环境的影响是不可否认的。例如，在奥运会和残奥会上，空气动力学的进步可以极大地影响我们国家在领奖台上的存在感。流量控制是一个关键的工具，可以减少阻力，从而节省能源，或最大限度地提高性能。***该研究项目的主题和长期愿景是开发和实施与加拿大航空和体育产业相关的新型基于物理的流量控制技术。在核心，该程序考虑流体动力学和控制边界层和流动分离。在这些流动方面的专业知识也是互补的，因为分离之前的边界层会影响尾迹和压力阻力。***该计划的基础是在流体动力学机制的间隙内创造知识，导致拖动作为最终寻求的控制创新的先驱。在体育运动中，不稳定运动对阻力的作用在很大程度上是未知的。该方法旨在从非定常运动的流动分离和涡流形成的研究出发，开辟减阻技术的新方向。从短期来看，重点在于未知的非定常偏航运动，这是运动员肢体运动的平行方面，是实现运动员更快的长期目标的基础。***针对湍流边界层中发生的高切变事件或旨在延迟过渡到湍流的主动流动控制系统，为减少飞机的环境足迹开辟了新的可能性。本研究的实验框架也固有地解决了与使用传感器和执行器相关的实际挑战，这些挑战与本研究支持的应用有关。短期目标是解决边界层对动态驱动的响应，在一个可处理的模型流动控制问题中，作为减少飞机阻力的长期研究愿景的一个组成部分。这个研究项目的实际成果是节约能源和提高性能。这项研究支持加拿大航空航天和以体育为基础的产业，以及加拿大运动员的卓越。这项研究也被设想为让公众了解空气动力学进步的重要性，并作为弥合科学、媒体和社区之间差距的催化剂。该计划的核心是HQP（2名博士，3名硕士，10名本科生），这将推进该计划，并为加拿大工业提供广泛的培训。

Aerodynamic drag is a form of loss that manifests through pressure and shear. For aircraft, engines produce thrust to overcome drag. In sport such as cycling, drag limits the speed an athlete can maintain. Reducing drag has a direct path to energy conservation or increasing performance. This is important because the impact of the consumption of non-renewable energy sources on our environment is undeniable. In Olympic and Paralympic Games, as examples, aerodynamic advancements can greatly affect our national presence at the podium. Flow control is a key tool that can reduce drag, and consequently, conserve energy, or maximize performance.*** The theme of this research program and long-term vision is the development and implementation of novel physics-based flow control technology for applications relevant to Canadian aeronautical and sport-based industries. At the core, this program considers the fluid dynamics and control of boundary layers and flow separation. Expertise in these flows is also complementary because the boundary layer preceding separation influences the wake and pressure drag. *** This program is underpinned by creating knowledge within the gaps of the fluid dynamic mechanisms leading to drag as a precursor to the control innovations ultimately sought. In sport, the role of unsteady motion on drag is largely unknown. The methodology is to build from the study of flow separation and vortex formation for unsteady motion to launch new directions in drag reduction technology. In the short-term, the focus resides on the uncharted unsteady yaw motions, which parallel aspects of athlete limb motions, and forms the basis to reach the long-term goal of faster athletes.*** Active flow control systems targeting high shear events occurring in the turbulent boundary layer, or aimed at delay of transition to turbulence, opens new possibilities in the reduction of the environmental footprint of aircraft. The experimental framework of this research also inherently addresses practical challenges associated with use of sensors and actuators that relate to the applications this research supports. The short-term objectives address the boundary layer response to dynamic actuation within a tractable model flow control problem as an integral component of the long-term research vision of reduced aircraft drag.*** The practical ramifications of this research program are in energy conservation and increased performance. This research supports the Canadian aerospace and sport-based industries, and excellence of Canadian athletes. This research is also envisioned to bring public exposure to the significance of aerodynamic advancements and act as a catalyst to bridge the gap between science, media, and the community. At the core of this program are the HQP (2 PhD, 3 MASc, and 10 Undergraduate) that will advance this program and bring extensive training to support Canadian industry.