Aircraft Environment and Flight Qualities Flight and Disturbances
Visualization of the wake of
an aircraft model
in the Lille B10 flight laboratory
The atmosphere in which an aircraft moves is not immobile. It is the seat of various motions, some of which are large scale, like the wind, and others on a much smaller scale, like turbulence or the disturbances created by the aircraft itself. That is, when an aircraft moves it creates a wake consisting of two large counter-rotating vortices which emanate from the wingtips and slowly decrease in intensity. A following aircraft can encounter such wake vortices.
All these disturbances will affect the flight and the stability of the aircraft. Among other phenomena, they can create vertical displacements and rolling motions that are especially dangerous if they occur when the aircraft is near the ground, such as in takeoff or landing phases.
In order to improve the aircraft flight qualities and safety, then, the characteristics of these disturbances and their impact on the aircraft need to be known. Much theoretical and especially experimental work is done on this in the new Flight Analysis Laboratory in Lille [B20].
