What trails behind the airfoil due to wingtip vortices?

• A. Vortices
• B. Turbulence
• C. Boundary layer
• D. Laminar flow

Answer: (A)

When a wing generates lift, air moves from the high-pressure underside to the low-pressure top, especially around the wingtips. This flow around the tips curls and forms rotating, spiral air masses that persist behind the wing. These rotating structures, known as vortices, trail in the wake of the airfoil. They’re the visible consequence of lift and produce wake turbulence that can affect other aircraft flying nearby. The boundary layer refers to the thin layer of air in contact with the surface, and laminar flow describes smooth, non-turbulent flow; neither describes the trailing rotating structures created by the wingtip effect. So the trailing feature produced by wingtip vortices is vortices.