Lift Management for Unsteady Translating Wings Using a Rotating, Swept Wing Tip

无人机在社会中的作用越来越大，既有民用应用，也有国防应用。一个关键的研究领域是开发小型、灵活的无人机，可以在复杂的环境中单独或成群机动。这样的场景包括搜救行动，跟踪有毒气体羽流，或收集大规模数据，如城市交通模式。然而，由于湍流和阵风，这些车辆在机动过程中很容易失去控制。该项目将寻求更好地了解和防止这种失去控制的情况，通过实时修改翼尖形状，以便在这些情况下控制升力。在带有定标机翼模型的水箱中进行成像和升力测量将为改进未来的飞行控制系统提供一个预测的数学模型。该项目也有一个外展计划，重点是指导女高中生、本科生和研究生，并通过动手研究吸引她们。拟议的研究的目标是调查可变翼尖的可行性，以控制大攻角、非定常平移过程中动态失速机翼的流动一致性和升力。在这种情况下，在机翼上方形成一个旋转的低压前缘涡旋，产生很大的升力，但随后会脱落。拟议的可移动翼尖将利用尖端旋涡控制来增加大迎角机动时的升力，或减少阵风时的升力。建议的可变翼尖是独一无二的，它结合了旋转和后掠翼，这应该会产生更附着和连贯的涡流和实质性的升力控制。实验将在水箱中用比例模型进行，使用染料可视化、力测量和立体粒子图像测速技术进行3D速度重建。实验结果将被用来开发改进飞行控制方法的预测模型。

Drone aircraft have an ever-increasing role in society, with both civilian and defense applications. A key research area is the development of small-scale, agile drones that can maneuver alone or in groups in complex environments. Such scenarios include search-and-rescue operations, tracking a toxic gas plume, or collecting large-scale data such as city traffic patterns. However, these vehicles are susceptible to loss of control during maneuvers because of turbulence and wind gusts. This project will seek to better understand and prevent this loss of control by modifying the wing-tip shape in real-time in order to control the lift force in these scenarios. Imaging and lift measurements in a water tank with a scaled wing model will lead to a predictive mathematical model for improved future flight-control systems. This project also has an outreach plan that focuses on mentoring female high-school, undergraduate, and graduate students and engaging them through hands-on research.The objective of the proposed research is to investigate the viability of a variable wing tip to control the flow coherence and lift for a dynamically-stalled wing during high-angle-of-attack, unsteady translation. In this scenario, a swirling, low-pressure leading-edge vortex forms over the wing and yields large lift, but then sheds. The proposed moveable wingtip will exploit tip-vortex control to increase lift for high-angle-of-attack maneuvers or reduce lift for gust alleviation. The proposed variable wing tip is unique, combining rotation with aft sweep, which should produce a more attached and coherent vortex flow and substantial lift control. Experiments will be performed with scaled models in a water tank, using dye visualization, force measurements, and stereo particle image velocimetry for 3D velocity reconstructions. The experimental results will be used to develop a predictive model for improved flight-control methods.