What is the function of a vortex generator?

• A. It increases the overall top speed by reducing drag in all flight regimes.
• B. It helps seal gaps and prevent leaks in fuel lines.
• C. It is designed to delay or prevent separation of the boundary layer.
• D. It reduces noise by masking turbulent structures.

Answer: (C)

Vortex generators are small vane-like devices that create a series of tiny, high-energy vortices along a surface. Those vortices energize the boundary layer, helping it resist adverse pressure gradients and delaying or preventing flow separation. By keeping the flow attached, they maintain lift and improve control effectiveness at high angles of attack or with high-lift devices deployed, reducing stall tendency. They aren’t designed to increase top speed across all regimes, seal fuel-line gaps, or primarily reduce noise, so their main purpose is boundary-layer control to keep the airflow attached.