Actuator Concepts for Active Gust Alleviation on Transport Aircraft at Transonic Speeds

Abstract

This paper investigates different concepts for active gust alleviation (GLA) on a generic transport aircraft configuration at transonic speed by means of viscous and inviscid CFD simulations. Four types of dynamic actuator concepts are presented including a fuselage flap, a wing tip flap, a trailing edge flap and a leading edge flap. The wing tip flap is investigated on a forward swept wing configuration being specifically designed for this purpose. The overall aerodynamic effect of the fuselage flap on the lift distribution is relatively small and has significant Phase angles relative to the flap motion. The wing tip flap instead, seems to be a promising approach to alleviate gusts, affecting the lift distribution on the complete wing. The dynamic trailing edge flap and leading edge flap are investigated on a representative 2.5D setup to derive the most effective actuator setup. The 2.5D simulations confirm the potential of the trailing edge flap allowing a compensation of about 95% of gust induced lift increase at moderate incidence angles, while the effect of the droop nose –in the way implemented so far– is much lower. Despite the rather small potential of the leading edge flap regarding lift force preservation, the time history of the pitching moment reveals its favourable effect on eliminating about 50% of the nose up moment induced by the upward deflected flap without significantly affecting the lift Response.