Manipulation of wing tip vortices on low aspect ratio wings using winglet control surfaces

摘要

The aerodynamic forces generated by a wing tip mounted articulated winglet control surface on a low aspect ratio wing in steady flight are investigated. The wings experimentally tested constitute two categories, traditional trailing edge mounted aileron flaps, and wing tip mounted articulated winglets which hinge chordwise. Low-aspect-ratio (LAR) wings at low-Reynolds numbers were chosen because these parameters are common to micro aerial vehicle (MAV) flight. Control authority developed by the control surface configurations were directly compared by measuring lateral forces and specifically the roll moment in wind tunnel testing. Flat plate wing models were studied to isolate the low aspect ratio aerodynamics from more complicated wing geometry effects. The manipulation of wing tip vortices' (TV) by articulated winglets is found to be an effective method of generating roll, especially in sideslip situations. We see conventional flaps generate a predictable roll moment varying slightly with angle of attack while articulated winglets rely on altering the span-wise distribution of lift. It is seen that in the delayed stall region, unique to LAR and delta wing flight, winglets generate the same authority as traditional flaps and develop greater authority in sideslip situations.