Lifting surfaces in low Reynolds number flows: bridging the gap between laboratory research and practice

低雷诺数流中的升力面：弥合实验室研究与实践之间的差距

• 批准号: RGPIN-2022-03352
• 负责人: Yarusevych, Serhiy
• 金额: $ 4.01万
• 依托单位: University of Waterloo
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=760455
• 关键词: Lifting; surfaces; low; Reynolds; number

The aerodynamic performance of many new and emerging technologies, ranging from modern turbofan engines to wind turbines to unmanned aerial/submersible vehicles, differs substantially from the predictions of classical aerodynamics. The relevant systems operate in the domain of low Reynolds number aerodynamics, where laminar flow separation leads to a degradation in system performance. Airfoil geometry optimization and flow control can be used to delay separation and/or to minimize the size of the separated flow region, thereby enhancing lift and decreasing drag. However, implementing these methods requires in-depth knowledge of the flow physics involving inherently complex laminar-to-turbulent transition and unsteady flow dynamics. Most prior work in this domain focused on two-dimensional airfoil configurations in steady incoming flows. In contrast, all relevant practical applications involve finite wings/blades exposed to unsteady incoming flows (e.g., wind gusts, wakes from upstream objects, etc.). The proposed program aims to bridge this research gap and advance the current state-of-the-art in low Reynolds number aerodynamics to practically relevant, finite-span lifting surface configurations operating in both steady and unsteady flow conditions, thereby enabling enhancement of system performance through design optimization and flow control. The main objectives of the proposed program focus on the effects of the three-dimensional geometry and temporal variations in the incoming flow parameters on the flow development over finite wings and the associated impact on their performance. This will be achieved by conducting novel experimental studies on both two-dimensional and finite-span models in a wind tunnel utilizing simultaneous state-of-the-art velocity and force measurements. Time-resolved and phase-averaged velocity measurements with advanced laser-based tools will be coupled with direct force measurements to provide unique insights into the flow development and the associated changes in loading. This will be complemented by novel pressure and sectional load estimations from the velocity data for improved insight into spanwise load distributions and dynamics. In addition to their novelty and significance for fundamental fluid mechanics, the results of the proposed research will have a strong impact on a wide range of modern and emerging applications. They will enable the design of more efficient lifting surfaces for wind turbines, small-scale propellers, aircraft engines, high-altitude platforms, unmanned aerial and underwater vehicles, as well as designing and implementing effective flow control strategies for further performance improvements. The program will also facilitate training of graduate students who will support the associated knowledge transfer and further research and development activities.

从现代涡轮风扇发动机到风力涡轮机再到无人机/潜水器，许多新兴技术的空气动力学性能与经典空气动力学的预测有很大不同。相关系统在低雷诺数空气动力学领域运行，其中层流分离导致系统性能下降。翼型几何形状优化和流动控制可用于延迟分离和/或最小化分离流动区域的尺寸，从而增强升力并减少阻力。然而，实现这些方法需要深入了解流动物理学，涉及固有复杂的层流到湍流的转变和非定常流动动力学。该领域的大多数先前工作都集中在稳定传入流中的二维翼型配置。相比之下，所有相关的实际应用都涉及暴露于不稳定传入流（例如阵风、来自上游物体的尾流等）的有限机翼/叶片。拟议的计划旨在弥合这一研究差距，并将当前低雷诺数空气动力学的最新技术发展到实际相关的、在稳定和非稳定流动条件下运行的有限跨度升力表面配置，从而通过设计优化和流量控制来增强系统性能。 该计划的主要目标集中于三维几何形状和传入流参数的时间变化对有限机翼上流动发展的影响以及对其性能的相关影响。这将通过利用同步最先进的速度和力测量对风洞中的二维和有限跨度模型进行新颖的实验研究来实现。使用先进的基于激光的工具进行时间分辨和相位平均速度测量将与直接力测量相结合，为流动发展和负载的相关变化提供独特的见解。这将得到来自速度数据的新颖压力和截面载荷估计的补充，以更好地了解展向载荷分布和动态。除了对基础流体力学的新颖性和意义外，所提出的研究结果还将对广泛的现代和新兴应用产生重大影响。它们将为风力涡轮机、小型螺旋桨、飞机发动机、高空平台、无人机和水下航行器设计更高效的升力面，并设计和实施有效的流量控制策略以进一步提高性能。该计划还将促进研究生的培训，他们将支持相关的知识转移和进一步的研究和开发活动。