Aerodynamic Optimisation of Non-planar Lifting Surfaces

Abstract

A novel population structured genetic algorithm (sGA) with embedded potential flow vortex ring panel method (VRM) has been developed to minimise induced and parasitic drag subject to constraints on lift, root bending moment, and longitudinal static stability. The optimisation architecture can activate up to four independent wing segments allowing up to 28 design variables. Minimum drag of wing tip extensions and winglet configurations are compared using the non-linear stochastic optimisation method. The optimiser identified joined box wings as offering the greatest induced efficiency followed by C-wings. With span and root bending moment constraints winglets offered best total drag reduction. C-wings are further investigated for potential to enhance longitudinal static stability performance by staggering the horizontal extension of the winglet to balance moments around the wing's centre of gravity. Preliminary results suggest that while longitudinal static stability can be reached it would be very poor. Inclusion of more design constraints and additional analysis of the structural dynamics of C-wings, especially effecting the torsional mode, is necessary.

Study of a C-wing configuration for passive drag and load alleviation

“…while the C-wing may achieve a total drag reduction, is it unlikely that it will provide the optimal reduction of induced drag. Each wing arrangement was designed using a in-house developed population structured genetic algorithm (sGA) which utilised an experimentally validated unsteady vortex-ring panel code 46 . This provided an effective design tool to ensure experimental constraints and design criteria could be met while maintaining characteristics of each wing arrangement.…”

Wake-Model Effects on Induced Drag Prediction of Staggered Boxwings

“…Highly non-planar configurations, such as boxwings or c-wings, have the potential to significantly reduce induced drag and, thus, have repeatedly been in the focus of research [7][8][9][10][11][12]. The inviscid aerodynamic advantage of these configurations can primarily be related to the bound circulation being distributed over a larger effective wingspan.…”