초록 ▼

An active noise suppression apparatus and method for reducing jet engine noise and buffeting. A plurality of resonant cavities are formed in a structural member disposed on or adjacent to a jet engine exhaust nozzle. Each resonant cavity opens toward an output slot. A compressed air chamber is used

An active noise suppression apparatus and method for reducing jet engine noise and buffeting. A plurality of resonant cavities are formed in a structural member disposed on or adjacent to a jet engine exhaust nozzle. Each resonant cavity opens toward an output slot. A compressed air chamber is used to supply a pressurized, supersonic jetstream airflow through the inlet port into the interior area of the resonant cavity. This causes a high frequency, pulsed, excitation airstream to be generated outwardly from the cavity, out of the output slot and into the developing shear layer of the exhaust airflow. This high frequency, pulsed, excitation airstream induces modifications in the shear layer, which leads to a major reduction in the noise and buffeting generated by the developing shear layer. In an alternative embodiment, the resonant cavities are formed within one wall of a slot, where the slot is disposed along the leading edge of a cavity of the aircraft. The excitation airstreams cause a modification in the shear layer of the airflow over the cavity to significantly reduce the noise level and buffeting by the developing shear layer.

대표청구항 ▼

1. An apparatus for reducing noise from a jet engine exhaust, comprising:an airflow directing system disposed adjacent a trailing edge of an exhaust nozzle of a jet engine; said airflow directing system forming a plurality of distinct chamber-like resonance elements disposed at least partially circu

1. An apparatus for reducing noise from a jet engine exhaust, comprising:an airflow directing system disposed adjacent a trailing edge of an exhaust nozzle of a jet engine; said airflow directing system forming a plurality of distinct chamber-like resonance elements disposed at least partially circumferentially about said exhaust nozzle, each of said resonance elements having an inlet port in communication with an interior area thereof; an outlet associated with each said resonance element for permitting airflow from said interior area of each of said resonant elements outwardly therefrom; wherein a pressurized airflow entering said inlet port of each said resonance element causes an oscillating excitation airstream to flow from said interior area of each said chamber out through said outlet and into a developing shear layer of airflow exiting from said exhaust nozzle; and whereby said oscillating excitation airstream induces modifications into said shear layer to thus reduce noise and buffeting generated by said shear layer.