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.