What is the primary function of a vortex generator?

The primary function of a vortex generator is to delay or prevent the separation of the boundary layer. This device creates small, controlled vortices that energize the airflow over the surface of the wing or other aerodynamic surfaces. By doing so, it helps keep the airflow attached to the surface for a longer distance, which reduces the occurrence of flow separation that can lead to stall conditions.

Maintaining attached airflow is crucial for ensuring optimal lift and overall aerodynamic efficiency, especially at higher angles of attack or in adverse flight conditions. This enhances the aircraft's performance and safety during operations.

The other options relate to aspects of aircraft operation but do not accurately describe the essential purpose of vortex generators. For instance, increasing aircraft weight is not a function of vortex generators and would generally be undesirable. While vortex generators can contribute to improved fuel efficiency and stability indirectly by enhancing lift characteristics, these are not their primary roles. Instead, the core function is focused on managing airflow and improving aerodynamic behavior.