De-Stabilization of Aircraft Wake Vortices

建议编号：CTS-9632579首席研究员：马库斯这项工作的目标是使商用飞机尾翼涡失稳。这是一个三十多年前就发现的长期存在的问题。这些涡流的强度如此之大，以至于即使是另一架商用喷气式飞机，如果在太近的距离遇到涡流结构，也可能会被打翻。60‘S和70’S飞机发生的一连串坠机事件要求美国联邦航空局为降落飞机设定严格的间距标准，这对我们机场的容量造成了严重影响。多年来，人们一直在努力寻找打破这些非常连贯的涡旋结构的方法，主要是通过对机翼及其操纵面进行改装。所有这些工作都没有产生任何实际用途。在这项研究中，通过在机翼尖端精确控制地注入少量流体来对尾迹涡进行微弱的修正。一种利用简并摄动理论的新的半解析方法将被用来探索导致快速增长的短波长不稳定性的注入流体的角度、位置、空间结构和时间速率的广泛组合。快速增长的短波长不稳定性的一个影响是使核心尺寸迅速增大，从而降低了旋流速度的强度。增加核心尺寸的第二个也可能是更重要的影响是增强了乌鸦不稳定机制在尾涡系统最终衰变中所起的作用。

ABSTRACT Proposal Number: CTS-9632579 Principal Investigator: Marcus The goal of this work is the destabilization of trailing tip vortices from commercial aircraft. This is a persistent problem that was identified more than thirty years ago. The strength of these vortices is so large that even another commercial jet can be upset if encountering a vortex structure at too close a range. A rash of crashes in the 60's and 70's required the FAA to set stringent spacing standards for landing aircraft that has had a severe impact on the capacity of our airports. Over the years there has been an intense effort directed at finding methods for breaking up these very coherent vortex structures, mainly through modifications to to the wing and its control surfaces. None of this work has lead to anything of practical use. In this study, wake vortices are weakly modified by injecting small amount of fluid at the wing tips in a precisely controlled manner. A novel semi-analytical method utilizing degenerate perturbation theory will be used to explore a broad range of combinations of angle, location, spatial structure and temporal rate of the injected fluid that leads to fast-growing short wave length instabilities. One effect of the fast-growing short wave length instabilities is to increase the core size quickly, which reduces the intensity of the swirl velocity. A secondary, and perhaps more important effect of increase core size is enhanced role that the Crow instability mechanism can play in the final decay of the trailing vortex system.