Numerical Aerodynamic Studies of Asymmetric Gust Entry

摘要

Lifting-surface calculations for a particular wing at Mach number 0.8 are used to examine the aerodynamic consequences when one side of an aircraft enters a vertical gust before the other. The growth of lift, pitching moment, aileron hinge moment and the behaviour of the transient rolling moment are analysed. Their dependence on the inclination of the gust front and the length of a (1-cosine) gust is discussed. Some idealized calculations of control-surface motion to suppress the wing root bending moment or to achieve undisturbed flight show only minor effects of gust inclination on control demand. But the transient rolling moment from asymmetric entry into a (1-cosine) gust within the spectrum of current airworthiness requirements is large enough to constitute a considerable handling problem. Ride control studies to eliminate heave, pitch and roll by means of two ailerons and an auxiliary tailplane or canard reveal distinct advantages of the canard as an active control. (Author)