What is the function of vortex generators mounted on the vertical fin?

The function of vortex generators mounted on the vertical fin is primarily to prevent flow separation over the rudder. Vortex generators create vortices that energize the surrounding airflow, thereby maintaining a smooth flow of air over the control surfaces, even at high angles of attack or during adverse flight conditions. This energized airflow helps keep the rudder effective, improving control and stability of the aircraft.

By maintaining attached flow, vortex generators enhance the overall aerodynamic performance of the vertical stabilizer and rudder, ensuring that the control surfaces remain responsive and effective throughout the operating envelope. This is especially critical during maneuvers where flow separation could lead to loss of control or decreased performance.

While enhancing aerodynamic stability is a benefit, the primary role of vortex generators is to manage airflow and prevent separation specifically at the rudder, which is crucial for responsive and stable flight.