What does the term "induced drag" refer to?

Induced drag is specifically associated with the generation of lift by an aircraft's wings. As an aircraft generates lift, it creates a pressure difference between the upper and lower surfaces of the wings. This pressure difference causes the air to move in a way that results in vortices forming at the wingtips, which effectively causes a force that acts opposite to the aircraft's motion—this is the induced drag.

The amount of induced drag varies with the angle of attack; at higher angles of attack, there's more lift generated, and consequently, more induced drag is present. This relationship is crucial in understanding how aircraft perform, especially during takeoff and low-speed flight. Induced drag becomes more significant at lower speeds and high angles of attack, which is a key aspect of aerodynamics.

Other types of drag, such as drag caused by the shape of the aircraft or airflow separation, do not directly relate to the generation of lift, which is the defining characteristic of induced drag. The occurrence of drag solely at high speeds is also not accurate, as induced drag is more pronounced at lower speeds when lift demands increase.