Control of spanwise flow induced separation on swept low aspect ratio wings to improve controllability

掠掠低纵横比平台，特别是那些前后缘对齐的平台，由于其固有的低可观测特性而越来越受到关注。然而，由于气流在适度迎角下发生破裂和分离，这些平台只能在“俯仰断裂”发生之前利用一小部分可用升力；俯仰力矩的迅速增加，通常导致偏离受控飞行。以前的工作已经确定了这种流动破裂的原因是在较大的迎角下引起的展向流动，导致流向机翼后部的流动分离。在对集成和系统故障模式的影响相对较小的情况下，在飞机的局部意义上应用主动流量控制（AFC）的机会已经确定。其中最有希望的是应用AFC来补充传统后缘控制在大迎角和/或大挠度下的有效性，以提高控制权威，并潜在地抵消分离时引起的大俯仰力矩。此外，最近在亚利桑那大学进行的研究已经确定了一个影响，即前缘的适量吹气可以影响展向流动及其对分离的影响；特别是当这种吹风振荡的形式是离散的“扫射射流致动器（sja）”。MAGMA研究飞机，最近在曼彻斯特大学开发，基于1303无人驾驶飞机平台，提供了一个合适的几何形状，以帮助理解扫掠，低展弦比几何形状的流动破裂的本质，也为未来的AFC和SJA测试提供了一个测试平台。在可能的情况下，MAGMA的飞行试验将为该项目收集数据，并允许在飞行环境中测试开发的新技术。

Swept low aspect ratio planforms, particularly those with aligned leading and trailing edges are of increasing interest due to their inherently low observable characteristics. Due to the process of flow breakdown and separation at moderate angles of attack however, these planforms only allow for a small amount of the available lift to be utilised before 'pitch break' occurs; a rapid increase in the pitching moment which generally leads to departure from controlled flight. Previous work has identified the cause of this flow breakdown to be the spanwise flow induced at higher angles of attack which leads to flow separation toward the rear of the wing.Opportunities to apply Active Flow Control (AFC) in a localised sense to an aircraft have been identified where the impact on integration and system failure modes are relatively benign. The most promising of these is applying AFC to supplement the effectiveness of conventional trailing edge controls at high angles of attack and/or large deflections to improve control authority and potentially counteract the large pitching moments induced at separation.Additionally, recent research conducted at the University of Arizona has identified an impact modest amounts of blowing from the leading edge can influence the spanwise flow and its effect on separation; particularly where this blowing is oscillatory in the form of discrete 'Sweeping Jet Actuators (SJAs)'.The MAGMA research aircraft, recently developed at the University of Manchester and based on the 1303 UCAV planform provides a suitable geometry to aid understanding in the nature of flow breakdown over swept, low aspect ratio geometries and also provides a test bed for AFC and SJA testing in the future. Where possible, flight trials of MAGMA will gather data for this project and allow the new technologies developed to be tested in a flight environment.