City Research Online

Abstract

Recent design and test concepts for small and medium fixed wing unmanned air vehicles (UAV) have considered new technologies of variable spanwise lift control for high-speed manoeuvring. In addition, solar powered, ultra-large wing span concepts for high altitude long endurance flights, need to be tested against gusts of variable strength along the span for their safe deployment. To address those questions in wind tunnel studies, a new concept of bio-inspired active flaplets has been developed, which can act as localised lift or gust control on aerofoils. Spanwise distributed actuators at the trailing edge are used for controlled opening and closing of the individual flaps. Causing an initial local suction and then successive blowing into the wake region, in the form of a tangential jet. This modifies the flow around the trailing edge and therefore the local circulation distribution. Furthermore, it interrupts the wake region during the time period when the tangential jet blowing happens. The segmented control regions can act independently of each other and allow for more complex control scenarios addressing localised separation cells or local gust alleviation. In addition, the concept can also be used to test the performance of aerofoils under complex inflow conditions, such as spanwise varying gusts. This can be achieved when the model is placed upstream of a wing and used as gust control unit at zero angle of attack (AoA). Disturbance patterns such as spanwise traveling waves, induced by individual flap deployment, or random artificial gust generation at different span locations can be achieved with arbitrary space-time control. The present paper covers the design, manufacture and testing of the concept with some initial results for the induced flow field when placed in a water tunnel for further research.

Publication Type:	Conference or Workshop Item (Paper)
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TL Motor vehicles. Aeronautics. Astronautics
Departments:	School of Science & Technology > Engineering

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