Plain English Meaning

Smooth, clean air flowing toward a wing or control surface that hasn't yet been stirred up or redirected by anything in front of it.

Full Definition

Air that is moving smoothly past a surface without having been disrupted by an upstream object, deflection, or turbulence. In aerodynamics, it refers to the free, steady airflow approaching a wing or control surface before that surface alters it.

Context Anchor

Seen in discussions of wings and control surfaces, including flaperons, where the quality of air moving over a surface affects how well it works.

Derivation

“Undisturbed” comes from “un-,” meaning “not,” and “disturbed,” meaning interrupted or thrown out of order. In aviation, it points to air that has not been interrupted or changed before it reaches the surface being discussed.