Abstract: An improved exhaust system including a lobed mixer and an improved exhaust centerbody is provided. The improved exhaust centerbody includes means for cooperating with the lobed mixer to increase mixing effectiveness of the exhaust system without substantially increasing pressure losses attributable thereto. In a preferred embodiment of the invention, the cooperating means include a plurality of circumferentially spaced elongated deformations, such as grooves and ridges, which deformations extend radially with respect to a reference surface of the exhaust centerbody and which deformations are aligned in an axial direction substantially parallel to a longitudinal axis of the centerbody.

Abstract: Nacelle installation having devices for constraining hot core exhaust gas from flowing over the trailing portion of a highly swept pylon supporting a high bypass turbofan engine. The devices can comprise a pylon ejector, a core nozzle shroud or a plurality of vortex generators and are disposed generally in the region adjacent the intersection of the core nozzle exit of the engine and the pylon shelf portion of the pylon.

Abstract: A propulsion nozzle having a substantially cylindrical translatable shroud partially defining an outer flow duct and an articulated plug mounted within the shroud to partially define an inner coannular flow duct. A variable position valve comprises the downstream portion of the common wall between the ducts for modulating the relative flow rates between ducts and for creating a favorable static pressure balance therebetween. The shroud and plug cooperate to form a variable area throat for the combined duct flows.