A method of reducing noise from a high-speed, including supersonic, jet, the method includes providing the high-speed or supersonic jet in a longitudinal flow direction; and inducing a rotation of a swirl layer of the high-speed or supersonic jet around a longitudinal direction of the jet and on the jet boundary so as to promote mixing of the high-speed or supersonic jet with surrounding air.

A method of reducing noise from a high-speed, including supersonic, jet, the method includes providing the high-speed or supersonic jet in a longitudinal flow direction; and inducing a rotation of a swirl layer of the high-speed or supersonic jet around a longitudinal direction of the jet and on the jet boundary so as to promote mixing of the high-speed or supersonic jet with surrounding air.

An engine exhaust nozzle for a jet engine offers a controllable variable mixing of engine exhaust and the surrounding airflow. The engine exhaust nozzle includes a nozzle, slots at the downstream end of the nozzle, curved vanes extending radially inward from the inner surface of the nozzle and adjacent to the slots, and a cover connected to the outside of the nozzle and movable with respect to the nozzle so as to open and close the slots. When the slots are opened, near-field mixing is enhanced between the jet exhaust and the surrounding air, thus reducing mixing further downstream and the noise associated therewith, thus reducing the overall noise transmitted to the ground. When the slots are closed, the nozzle propulsive efficiency improves at the expense of increased noise.

A propulsion system includes at least one compressor, multiple conduits, a multiple-way valve, and at least one thrust augmentation device. A series of flaps can be retracted, tilted and operated in conjunction with the at least one thrust augmentation device. A converging channel in fluid communication with the valve is configured to allow expansion to ambient of a compressed air stream in a preferred single direction. The at least one thrust augmentation device each contains a mixing section, a throat section and a diffusor. Each said augmentation device receives compressed air from the at least one compressor via at least one of the conduits and valve and uses pressurized air as motive gas to generate thrust by fluidically entraining ambient air, mixing it with the motive gas and ejecting the motive gas at high velocities via the diffusor.

A propulsion system includes at least one compressor, multiple conduits, a multiple-way valve, and at least one thrust augmentation device. A series of flaps can be retracted, tilted and operated in conjunction with the at least one thrust augmentation device. A converging channel in fluid communication with the valve is configured to allow expansion to ambient of a compressed air stream in a preferred single direction. The at least one thrust augmentation device each contains a mixing section, a throat section and a diffusor. Each said augmentation device receives compressed air from the at least one compressor via at least one of the conduits and valve and uses pressurized air as motive gas to generate thrust by fluidically entraining ambient air, mixing it with the motive gas and ejecting the motive gas at high velocities via the diffusor.

An exhaust passage including a protrusion which is less likely to receive heat from a gas and hence has high heat-resistance reliability is provided. An exhaust passage includes an exhaust pipe, and a protrusion continuously formed over a range of a part of an inner surface of the exhaust pipe in a circumferential direction thereof, the protrusion being inclined toward a direction in which the exhaust pipe extends, and being configured in such a manner that a cross-sectional area of the exhaust pipe becomes smaller toward a downstream side thereof, in which the exhaust passage further includes a convex part on an inner surface of the protrusion.

A propulsion system is provided including an unducted rotating fan defining a fan axis; and a turbomachine disposed downstream from the unducted rotating fan, wherein the turbomachine defines a working gas flowpath flowing therethrough; wherein the propulsion system defines a third stream flowpath and an inlet passage having an inlet that is offset from the fan axis, wherein the inlet passage is configured to provide an inlet airflow to the working gas flowpath, and wherein the third stream flowpath bypasses at least a portion of the turbomachine.

A propulsion system is provided including an unducted rotating fan defining a fan axis; and a turbomachine disposed downstream from the unducted rotating fan, wherein the turbomachine defines a working gas flowpath flowing therethrough; wherein the propulsion system defines a third stream flowpath and an inlet passage having an inlet that is offset from the fan axis, wherein the inlet passage is configured to provide an inlet airflow to the working gas flowpath, and wherein the third stream flowpath bypasses at least a portion of the turbomachine.

Lobed mixer nozzles for supersonic and subsonic aircraft, and associated systems and methods are disclosed herein. A representative lobe mixer nozzle includes a fan flow duct aligned along a longitudinal axis, and a core flow duct, also aligned along the longitudinal axis. At least one duct wall, for example, a splitter, forms, at least in part, a radially inner boundary of the fan flow duct, and a radially outer boundary of the core flow duct. The duct wall terminates at a reference exit plane, and has multiple first lobes extending radially inwardly, and multiple second lobes extending radially outwardly. At least one lobe is canted forward relative to the reference exit plane, and at least one lobe is canted aft relative to the reference exit plane.

Lobed mixer nozzles for supersonic and subsonic aircraft, and associated systems and methods are disclosed herein. A representative lobe mixer nozzle includes a fan flow duct aligned along a longitudinal axis, and a core flow duct, also aligned along the longitudinal axis. At least one duct wall, for example, a splitter, forms, at least in part, a radially inner boundary of the fan flow duct, and a radially outer boundary of the core flow duct. The duct wall terminates at a reference exit plane, and has multiple first lobes extending radially inwardly, and multiple second lobes extending radially outwardly. At least one lobe is canted forward relative to the reference exit plane, and at least one lobe is canted aft relative to the reference exit plane.