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.

许多新的和新兴技术的空气动力学性能，从现代涡轮发动机到风力涡轮机到无人驾驶/潜水车辆，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的域中运行，其中层流分离导致系统性能的降解。机翼几何优化和流控制可用于延迟分离和/或最小化分离流动区域的大小，从而增强升力和减少阻力。但是，实施这些方法需要深入了解涉及固有复杂层流到扰动的过渡和不稳定流动动力学的流体物理学。该域中的大多数先前工作都集中在稳定传入流中的二维机翼配置上。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的有限翼/叶片（例如，风阵，上游对象的唤醒等）。拟议的计划旨在弥合这一研究差距，并将低雷诺数量空气动力学中的当前最新设备推进到在稳定和不稳定的流动条件下运行的实际相关的有限跨度提升表面配置，从而通过设计优化和流动控制来增强系统性能。 拟议程序的主要目标集中于传入流参数对有限机翼流量发展的三维几何形状和时间变化的影响，以及对其性能的相关影响。这将通过对二维和有限跨度模型进行风洞中的二维和有限跨度模型进行新的实验研究，利用同时最先进的速度和力测量。具有高级激光工具的时间分辨和相平均速度测量将与直接的力测量相结合，以提供对流量发展和相关负载变化的独特见解。这将通过速度数据中的新型压力和分段负载估计来补充，以改善对跨度负载分布和动态的见解。除了它们对基本流体力学的新颖性和重要性外，拟议的研究结果还将对广泛的现代和新兴应用产生强大的影响。它们将为风力涡轮机，小规模的螺旋桨，飞机发动机，高海拔平台，无人驾驶空中和水下车辆以及设计和实施有效的流量控制策略以进行进一步改善的有效流程控制策略，以设计更有效的举重表面。该计划还将促进研究研究生的培训，这些研究生将支持相关的知识转移和进一步的研发活动。