Aerodynamic Efficacy of Changing the Chordwise Installation Position of Multi-winglet on Commercial Aircraft

This study investigated multi-winglet availability in transonic civil aircraft and the aerodynamics of changing the winglet attachment position for the main wing. Multi-winglet decreases drag for wingtip vortex dispersion and increases lift due to gaps between the winglets, but previous studies have only been investigated under subsonic conditions. Also, the past perspective was on the effect validation of the winglet pluralization; no study was performed regarding the position of the multi-winglet on the main wing. We diverted this multiplying concept to a transonic civil aircraft and analyzed the aerodynamics of its model with three nonplanar winglets placed on the upwind and downwind sides of the main wing. Furthermore, we compared the results to the computational mode without any winglet. As a result, both multi-winglet models improved the lift-to-drag ratio of the whole body compared to the no-winglets model because the connection of the winglets and the main-wing shock waves enhanced lift by expanding the negative pressure area on the main wing to the multi-wing tips. Moreover, the lift-to-drag ratio of the downwind type was higher than the upwind type because each shock wave on the multi-winglet extended by the shock on the main wing in the upwind type, which increased the wave drag.