Ground-effect aerodynamics and wingtip vortex and their control

长期目标是将地效空气动力学纳入飞机，包括旋翼飞机，MAV（微型航空器）和eVTOL（电动垂直起降车辆），靠近地面飞行，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和更安静、更安全的飞行，同时减少环境特征和影响。因此，地面效应的研究具有重要的理论意义和实际意义。增强的地面效应产生的升力增加和阻力减少也将提高环境友好型有翼地面效应飞行器的空气动力学效率;加拿大广阔的湖泊和冰冻土地的潜在货物和乘客运输。 在接下来的5年里，该研究计划将研究静态和振荡机翼的空气动力学特性和流动物理学及其在地面上的控制。在地面效应中，振荡翼型和机翼是两个有趣的和众所周知的研究课题。尽管对这两个主题的许多研究工作，仍然需要大量的努力来调查这两个主题在一起。为了弥补这一差距，将在麦吉尔的风洞中综合使用各种常规和激光/光学流动诊断技术，对地面效应空气动力学（包括翼尖涡）以及静态和振荡机翼的流场进行广泛的测量，包括通过独特的多元件热膜传感器（MHFS）阵列进行独特的边界层转捩和分离检测（在麦吉尔大学设计和制造）。这些测量结果也将作为地面效应中升力和阻力控制的准则。为了使地面效应研究实用化，研究了均匀和非均匀地面。该研究计划包括几个步骤： (1)地面效应产生的升力增加和翼尖涡流引起的静态和振荡机翼和翼型的阻力减小的测量和特性。 (2)通过使用MFHS阵列非侵入性地和实时地识别地面效应中的边界层转捩和分离以及动态失速流动事件。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准则。 (3)包括表面粗糙度在内的非均匀地面效应对空气动力学和翼尖涡流及其控制的研究。 工程师和研究人员必须在这类研究中尽自己的一份力量，以便生产出在地面效应下运行的更具空气动力学效率的车辆，并最终减少其对环境的影响。这项研究的好处将提供HQP（3个博士，4个硕士和5个本科实习生），直接旨在推进国家的航空航天工业和我们的环境的可持续性。

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.