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

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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.