Abstract: Jet engine nozzles with projections (e.g., chevrons) and injected flow, and associated systems and methods are disclosed. A method in accordance with one embodiment includes generating a first flow of gas with a jet engine, delivering the first flow through a nozzle having a trailing edge perimeter that includes multiple projections extending in an aft direction, and injecting a pressurized second flow of fluid into the first flow proximate to the projections. In other embodiments, other mixing enhancement devices (e.g., vortex generators) are carried by the projections. It is expected that the combination of the projections and the mixing enhancement devices will reduce engine exhaust noise levels below the levels achievable with either projections or injected flow individually.

Abstract: Jet engine nozzles with projections (e.g., chevrons) and injected flow, and associated systems and methods are disclosed. A method in accordance with one embodiment includes generating a first flow of gas with a jet engine, delivering the first flow through a nozzle having a trailing edge perimeter that includes multiple projections extending in an aft direction, and injecting a pressurized second flow of fluid into the first flow proximate to the projections. In other embodiments, other mixing enhancement devices (e.g., vortex generators) are carried by the projections. It is expected that the combination of the projections and the mixing enhancement devices will reduce engine exhaust noise levels below the levels achievable with either projections or injected flow individually.

Abstract: 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.

Abstract: An exhaust flow nozzle for a jet engine having a plurality of flow altering components extending from a lip portion of a secondary exhaust nozzle that are movable between first and second positions. In the first position the flow altering components are disposed substantially parallel to an exhaust gas flow path and thereby do not produce drag or a reduction of thrust from the engine. In the second position the flow altering components bend or are deformed to project into the exhaust gas flow path exiting from the secondary exhaust nozzle. The flow altering components are comprised of a shape-memory alloy material which deforms in response to heat. One or more additional layers of material are bonded or otherwise coupled to the shape-memory alloy layer of each flow altering component to assist in returning the shape-memory alloy layer to its unheated shape.

Abstract: 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.

Abstract: An exhaust flow nozzle for a jet engine having a plurality of flow altering components extending from a lip portion of a secondary exhaust nozzle that are movable between first and second positions. In the first position the flow altering components are disposed substantially parallel to an exhaust gas flow path and thereby do not produce drag or a reduction of thrust from the engine. In the second position the flow altering components bend or are deformed to project into the exhaust gas flow path exiting from the secondary exhaust nozzle. The flow altering components are comprised of a shape-memory alloy material which deforms in response to heat. One or more additional layers of material are bonded or otherwise coupled to the shape-memory alloy layer of each flow altering component to assist in returning the shape-memory alloy layer to its unheated shape.

Abstract: A process is provided for repairing design defects or damage in a decorative surface. Repair patches are made at the same time that the decorative surface is prepared. Any defects in a decorative surface are corrected by a repair patch which has the same pattern as the decorative surface. The repair patch is specifically made so that it can be applied to the decorative surface to conceal defects in the decorative surface.