Near the wingtips, what creates vortices that trail behind the airfoil?

• A. Turbulence
• B. Vortices
• C. Wake turbulence
• D. Boundary layer separation

Answer: (B)

When a wing generates lift, air moves from the high-pressure underside to the low-pressure top side, and this flow wraps around the wingtips. The pressure difference creates a circulation that rolls the air into a pair of rotating streams, which then trail behind the wing as a connected pair of rotating structures. These trailing rotating flows are wingtip vortices, so the best description of what creates them is vortices.

Turbulence is a general, chaotic motion in the flow and doesn’t specifically describe the cause. Wake turbulence refers to the overall disturbed air behind an aircraft (which includes the vortices but isn’t the direct mechanism). Boundary layer separation is about the flow detaching from the surface, not the creation of the wingtip vortices themselves.