Abstract: A turbofan engine includes a fan variable area nozzle having a multiple of vents through a fan nacelle and a sleeve system movable relative to the vents by an actuator system. The fan variable area nozzle changes the effective area of the fan nozzle exit area to permit efficient operation at predefined pressure ratios. The vents include a grid structure which directs and smoothes the airflow therethrough as well as to reduce noise generation.

Abstract: A turbofan engine includes a fan variable area nozzle having a multiple of vents through a fan nacelle and a sleeve system movable relative to the vents by an actuator system. The fan variable area nozzle changes the effective area of the fan nozzle exit area to permit efficient operation at predefined pressure ratios. The vents include a grid structure which directs and smoothes the airflow therethrough as well as to reduce noise generation.

Abstract: The invention is a method and apparatus for combining two fluid streams, for example concentric inner (42) and outer (44) fluid streams in a turbine engine, thereby reducing noise emissions of the engine. A mixing system (12) according to the invention has a convoluted mixer body (18) and a fluid communication path (88) situated forwardly of a main mixing zone (54) for inducing a small quantity of fluid to flow from one of the streams and into the other of the streams in response to a differential pressure between the streams. In one specific embodiment, the fluid communication path (88) is a series of circumferentially distributed crossover apertures (92) forwardly of the leading edge (48) of the mixer body (18). In operation, the mixing system circumferentially interleaves the inner and outer streams of a turbine engine and introduces a quantity of fluid from one of the streams into the other of the streams, the fluid introduction occurring prior to or concurrently with the interleaving.