System for reducing aerodynamic noise at a supplementary wing of an aircraft

A system for reducing aerodynamic noise of a supplementary wing of an aircraft, comprising:

• a portion of the supplementary wing hinged to the main wing, extendable to open a gap region between the main wing and the supplementary wing;
• a separating surface movable into the gap region when the supplementary wing is extended, the separating surface extending at least partially along a separation flow line between a vortex flow region and a gap flow region of air flowing in the gap region between the supplementary wing and the main wing, the separation surface being an n-stable surface;
• and
• an actuator device for moving the separating surface between at least one stable state position and at least one additional position;
• wherein the actuator device comprises a rotary actuator coupled to the separating surface on at least one side on which the separating surface is supported along a line extending in the spanwise direction, thereby moving the separating surface between the at least one stable state position and the at least one additional position,
• wherein the separating surface is a bistable surface having two stable state positions between which the separating surface is moveable by actuation of the actuator, and
• wherein the stable states of the bitable separating surface are automatically established by at least one of spring-elastic structural properties of the separating surface, locking devices, and a spring device.