Optimising wing lift distribution to minimise wake vortex hazard

Abstract

AbstractThe aim of this work is to investigate how the wake vortex hazard generated by an aircraft can be reduced by modifying the wing lift distribution. The wake associated with a given lift distribution is simulated with a two-dimensional, in viscid ‘vortex method’. A numerical optimisation technique is used to guide the modifications so that a hazard measure, based on the rolling moment induced on a following aircraft encountering the wake, is minimised. The results show that a significant (~20–25%) reduction in hazard compared with conventional high-lift configurations can be achieved, via lift distributions that have a local minimum between the regions contributing to the flap and tip vortices. The counter-signed vorticity associated with this minimum appears to prevent the tip and flap vortices from merging, resulting in a safer wake. Furthermore, the hazard reduction is robust to variations in other features of the lift distribution and should thus be achievable in practice.