Study of vortex stability in swept wing configurations using theory, experiment and simulation

利用理论、实验和仿真研究后掠翼构型的涡稳定性

• 批准号: 2442021
• 金额: --
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2442021
• 关键词: Study; vortex; stability; swept; wing

Swept wing planforms enable highly-agile and high-lift flight in aircraft and UAVs. The most important flow feature on such planforms is the unsteady leading-edge vortex (LEV) which is created owing to flow separation from the edges of the wing. This creates a low-pressure area on the suction side of the wing, enabling high lift and maeuverability. LEVs however are subject to instabilities which could lead to vortex breakdown. A better understanding of the instabilities and the development of flow-control methods to alleviate or eliminate them could contribute to an extension of the flight envelope in delta-wing based UAVs and aircraft. This project aims to develop new analytical and low-order numerical methods for representing vortex-based flight on swept-wing configurations. The novel aspects of the proposed research are to study the flow in a fully unsteady sense, and to develop a dynamical model for the system based on critical points (such as half saddles, full saddles and nodes) in the flow. To support the development of theoretical and numerical models, the critical points in 3D LEVs will be systematically studied using experiments. Experimental work will be conducted using the University of Glasgow's subsonic wind tunnel facilities. Advanced flow diagnostic techniques (stero-Particle Image Velocimetry, smoke flow visualisation, 3D Laser Doppler Anemometry, and unsteady Pressure Sensitive Paints) and a 6 component sting balance will be used. The locations and characteristics of vortex enhancement, breakdown and trajectories in particular will be looked for. The experimental setup includes a custom-built pitch-plunge-surge facility developed that is comprised of three linear actuators, controlled through LabVIEW, to create the different motions to investigate leading edge separation Transient CFD simulations (using an in-house OpenFOAM implmentation) will also be used to mutually validate experiments and to support model development. Further understanding of the interaction mechanisms between LEVs will allow wings to be designed to operate more efficiently and safely. Understanding of the conditions in which different types of stable LEV configurations exist will aid in avoidance and control of vortex breakdown events, and enable safe operation within the envelope of conditions where favorable LEVs exist. Using the knowledge gained, flow control for sustaining stable vortices will be investigated in the final phase of the project. Passive (vortex generators, surface roughness elements) and active (suction/blowing, plasma actuators) strategies will be considered.

后掠翼平面形状使飞机和无人机能够实现高敏捷和高升力飞行。在这种平面形状上最重要的流动特征是非定常前缘涡（LEV），它是由于机翼边缘的气流分离而产生的。这在机翼的吸力面上形成了一个低压区，从而实现了高升力和可操纵性。然而，LEV容易受到不稳定性的影响，这可能导致涡流破裂。更好地理解不稳定性和发展流动控制方法来减轻或消除它们可能有助于扩展三角翼无人机和飞机的飞行包线。这个项目的目的是发展新的分析和低阶数值方法来表示后掠翼布局上基于涡的飞行。所提出的研究的新颖方面是在一个完全不稳定的意义上研究流动，并开发一个动态模型的系统的基础上的临界点（如半鞍，全鞍和节点）的流量。为了支持理论和数值模型的发展，将使用实验系统地研究3D LEV中的临界点。实验工作将利用格拉斯哥大学的亚音速风洞设施进行。将使用先进的流动诊断技术（立体粒子图像测速法、烟流可视化、3D激光多普勒风速测定法和不稳定压敏涂料）和6组分支杆天平。特别是将寻找涡增强、破裂和轨迹的位置和特征。实验装置包括一个定制的俯仰-俯冲-喘振设备，该设备由三个线性致动器组成，通过LabVIEW控制，以创建不同的运动来研究前缘分离瞬态CFD模拟（使用内部OpenFOAM implmentation）也将用于相互验证实验并支持模型开发。进一步了解LEV之间的相互作用机制将允许机翼设计成更有效和安全地运行。了解不同类型的稳定LEV配置存在的条件将有助于避免和控制涡破裂事件，并在有利LEV存在的条件范围内实现安全操作。利用所获得的知识，将在项目的最后阶段研究维持稳定涡流的流量控制。被动（涡流发生器，表面粗糙度元素）和主动（吸/吹，等离子致动器）的战略将被考虑。