Patent ID: 8443931

Claim:
A jet engine adapted for reducing far-field noise levels, the jet engine comprising: a plurality of flap assemblies disposed around a perimeter of an exhaust port of the jet engine, each flap assembly movable between a first position and a second position, each flap assembly comprising a convergent flap having first and second ends and a divergent flap having first and second ends, the first end of the convergent flap being rotatably coupled to an airframe, the first end of the divergent flap being rotatably coupled to the second end of the convergent flap, an area circumscribed by the second ends of the plurality of convergent flaps forming a throat, and an area circumscribed by the second ends of the plurality of divergent flaps forming an exit; a plurality of convergent actuators respectively coupled to the plurality of convergent flaps; a plurality of divergent actuators coupled to the plurality of divergent flaps; and a controller operably coupled to each actuator, wherein the controller is configured to cause at least one actuator to move the coupled flap assembly between the first and second positions at a determined frequency, and wherein the controller is configured to cause the plurality of flap assemblies to move so as to vary the area of at least one of the throat and the exit, and wherein the controller is configured to vary the area of the throat by a first amount and the area of the exit by a second amount.