Ground-effect aerodynamics and wingtip vortex and their control

长期目标是将地效空气动力学技术应用到飞行器中，包括旋翼飞行器、微型飞行器（MAVs）和电动垂直起降飞行器（eVTOLs），这些飞行器可以贴近地面飞行，以优化其空气动力学性能。优化的空气动力学性能将带来更好的燃油效率，更安静、更安全的飞行，减少环境特征和影响。因此，地面效应研究具有重要的基础和现实意义。增强的地效产生的升力增加和阻力减少也将提高环保翼型地效飞行器的气动效率；它是加拿大广阔湖泊和冰原的潜在货运和客运运输工具。在接下来的5年里，这个研究项目将研究静态和振荡机翼的空气动力学特性和流动物理特性，以及在地面存在下的控制。振动翼型和机翼的地面效应是两个有趣而知名的研究课题。尽管对这两个主题进行了大量的研究工作，但将这两个主题放在一起研究仍然需要付出很大的努力。为了弥补这一差距，将在麦吉尔的风洞中使用各种传统和激光/光学流动诊断技术，包括通过独特的多元素热膜传感器（MHFS）阵列（麦吉尔大学设计和制造）进行独特的边界层过渡和分离检测，来获得广泛的地效应空气动力学测量，包括翼尖涡，静态和振荡机翼的流场。这些测量也将作为地面效应升力和阻力控制的指导方针。为了使地面效应研究更加实际，研究了均匀和非均匀地面。该研究计划包括以下几个步骤：(1)测量和表征静态和振荡机翼和翼型的地面效应产生的升力增加和翼尖涡升力诱导的阻力减少。(2)利用MFHS阵列非侵入式实时识别地效应边界层过渡分离和动态失速流动事件。这些测量结果将作为地面效应下非定常机翼升力和阻力控制的实验指导。(3)非均匀地面效应（包括表面粗糙度）对空气动力学和翼尖涡的影响及其控制研究。工程师和研究人员必须在这类研究中尽自己的一份力量，以生产出在地面效应下运行的空气动力学效率更高的车辆，并最终减少它们对环境的影响。这项研究的好处将提供HQP（3名博士，4名硕士，5名本科生实习生），直接针对推进国家的航空航天工业和我们的环境的可持续发展。

The long-term objective is the incorporation of ground-effect aerodynamics into aircraft, including rotorcraft, MAVs (micro aerial vehicles) and eVTOLs (electric vertical takeoff and landing vehicles), flying close to the ground to optimize their aerodynamic performance. The optimized aerodynamic performance will lead to a better fuel efficiency and a quieter and safer flight with a reduced environmental signature and impact. The ground effect research is thus of both fundamental and practical significance. The enhanced ground effect-produced lift increase and drag decrease will also advance the aerodynamic efficiency of environmentally friendly winged ground-effect vehicles; a potential cargo and passenger transportation for Canada's vast lakes and iced lands. Over the next 5 years, this research program will investigate the aerodynamic properties and flow physics of both static and oscillating wings and its control in the presence of the ground. Oscillating airfoils and wings in ground effect are two interesting and well-known research subjects. Despite the numerous research work on both subjects, much effort is still needed to investigate these two subjects together. To bridge this gap, extensive measurements of the ground-effect aerodynamics, including wingtip vortex, and flowfield of both static and oscillating wings will be acquired in McGill's wind tunnels by using a combination of various conventional and laser/optics flow diagnostic techniques, including the unique boundary-layer transition and separation detection through the unique multi-element hot-film sensor (MHFS) arrays (designed and fabricated at McGill University). These measurements will also serve as guidelines for lift and drag control in ground effect. To practicalize the ground-effect research, both uniform and non-uniform ground surfaces are investigated. The research program involves several steps: (1) Measurement and characterization of ground effect-produced lift increase and wingtip vortex lift-induced drag reduction of static and oscillating wings and airfoils. (2) Identification of boundary-layer transition and separation and dynamic-stall flow events in ground effect both non-intrusively and in real-time via the use of MFHS arrays. These measurements will then serve as experimental guidelines for lift and drag control of unsteady wings in ground effect. (3) Investigation of non-uniform ground effect, including surface roughness, on aerodynamics and wingtip vortex and their control. It is essential for engineers and researchers to do their part in this type of research for the sake of producing more aerodynamically efficient vehicles operating in ground effect and ultimately reducing their impact on the environment. The benefits of this research will provide HQP (3 PhDs, 4 Masters, and 5 undergraduate interns) that are directly aimed at advancing the nation's aerospace industry and the sustainment of our environment.