Investigation of the effect of winglet geometry on aerodynamic performance of the onera M6 wing

It is known that the use of winglets in aircraft provides fuel efficiency by reducing drag. The main function of the winglets, various examples of which are found especially in civil aviation, is to mitigate the vortices generated at the wingtips. This leads to a reduction in induced drag. In this study, single winglet and double winglet models were created, taking the ONERA M6 wing as a baseline geometry. The effect of the change in the cant angle of the winglets on the aerodynamic performance for different speed and angle of attack conditions was investigated through Computational Fluid Dynamics (CFD) analysis. The results obtained showed that the cant angle has a significant effect on aerodynamic performance. Along with varying the cant angle for the single winglet wing, an aerodynamic efficiency increase of up to 14% was achieved compared to the wing without winglet. The current design of the wing with two winglet has a lower CL/CD ratio compared to the wing with single winglet at transonic speeds, but it provides an efficiency increase of up to 2.9% in relatively lower speed (Ma = 0.3) and high angle of attack conditions. In addition, the fact that there is no single cant angle that provides the best results for all flight conditions shows that designs that can change the cant angle according to flight conditions may have superior performance compared to conventional winglet designs with fixed cant angles.