Vortex Flow Control Using Fillets and Fences on the Flying V

Abstract

The aviation industry is exploring unconventional aircraft designs like the Flying V in its drive to reduce carbon emissions and improve fuel efficiency. The Flying V, featuring a crescent wing with leading edge kink, currently suffers from an unstable nose-up pitch tendency. This study investigates vortex control methods within this kink region to increase lift on the outboard wing and delay the pitch-break. A full-span, modular wind tunnel model is used to investigate the effects of parabolic and diamond juncture fillets, as well as full-chord fences, on the pitching moment characteristics. Stereoscopic Particle Image Velocimetry (SPIV) and oil flow visualization are used to analyse vortex behaviour and flow topology. Results reveal that the parabolic fillet outperforms the diamond fillet in generating lift at higher angles of attack due to its ability to promote vortex formation and delay breakdown. The installation of full-chord fences increases lift on the outboard wing and positively influences the pitching moment, though none of the tested configurations increased the pitch-break angle.