Definition
A theoretical vortex considered to be fixed within the wing of an aircraft producing lift. The bound vortex represents the circulation of air around the wing that, combined with the forward motion of the aircraft, produces the pressure difference between the upper and lower surfaces responsible for lift.
Plain English
A pattern of swirling airflow thought of as locked inside the wing itself. It explains, in theory, how the wing pushes air to create lift as the aircraft moves forward.
Context Anchor
Seen in aerodynamics discussions of lift, wingtip vortices, downwash, and lift-related drag.
Derivation
Bound here means held in place or fixed, from the Old English bindan (to tie). The vortex is bound because it is treated as attached to the wing, in contrast to the trailing vortices that stream behind the wingtips.
Why Pilots Care
It explains the basic mechanism by which a wing generates lift.
Analogy
Think of it as the part of a larger spinning-air pattern that stays with the wing as the aircraft moves forward, while the ends of that pattern trail behind in the air.
Grounding Statement
When a wing is lifting, the air around it does not just move straight back; it also has a rotating pattern tied to the wing.
Intuition Check
Bound does not mean the airplane is headed somewhere. Here, bound means treated as attached to the wing.
Example Sentence 1
The instructor explained that the bound vortex around the wing, together with the aircraft's forward speed, accounts for the lift the wing produces.
Example Sentence 2
Students examined how the bound vortex strength changes from root to tip on a tapered wing.