High frequency jet nozzle actuators for jet noise reduction

摘要

A noise reduction system for use with an exhaust nozzle associated with a jet engine of an aircraft. The noise reduction system employs a plurality of flow-altering components disposed circumferentially about a lip portion of an exhaust nozzle. In one preferred form the flow-altering components each comprise piezoelectric transduction layers. The flow-altering components are caused to move in an oscillating manner by an AC signal applied thereto such that they move into and out of the exhaust gas emitted from the exhaust nozzle to achieve a desired degree of intermixing of the exhaust flow with the flow adjacent the exhaust nozzle. This produces a reduction in the noise generated by the jet engine. The noise reduction can be utilized during takeoff conditions of an aircraft. The flow-altering components are maintained out of the exhaust gas flowpath during cruise conditions of the aircraft so as not to cause a reduction of thrust, that would in turn result in an increase in the fuel burn during cruise conditions.