De-Stabilization of Aircraft Wake Vortices

飞机尾流涡的失稳

• 批准号: 9632579
• 负责人: Philip Marcus
• 金额: $ 25万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-08-15 至 2000-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9632579&HistoricalAwards=false
• 关键词: De; Stabilization; Aircraft; Wake; Vortices

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.

摘要 提案编号： CTS-9632579 主要研究者：马库斯 这项工作的目标是从商业飞机的尾梢涡的不稳定性。 这是30多年前就发现的一个长期存在的问题。 这些涡流的强度是如此之大，以至于即使是另一架商用喷气式飞机，如果在太近的范围内遇到涡流结构，也会被打乱。 60年代和70年代的一系列坠机事件要求联邦航空局为降落飞机制定严格的间隔标准，这对我们机场的容量产生了严重影响。 多年来，人们一直在努力寻找打破这些非常连贯的旋涡结构的方法，主要是通过修改机翼及其操纵面。 这些工作都没有产生任何实际用途。 在这项研究中，尾涡弱修改，通过在翼尖注入少量的流体在一个精确控制的方式。 一种新的半分析方法，利用简并微扰理论将被用来探索一个广泛的角度，位置，空间结构和注入流体的时间速率，导致快速增长的短波长不稳定性的组合。 快速增长的短波长不稳定性的一个影响是快速增加核心尺寸，这降低了旋流速度的强度。 增加核心尺寸的第二个，也许是更重要的影响是，Crow不稳定机制在尾涡系统的最终衰减中可以发挥更大的作用。