Apparatus and methods for active flow control of a nozzle exhaust plume

An active flow control apparatus for enhancing mixing of a nozzle exhaust plume downstream of an exit plane of a primary nozzle, comprising:

• at least first and second pulsed jet nozzles circumferentially spaced apart near a radially outermost boundary of the exhaust plume, the pulsed jet nozzles being constructed and arranged to direct pulsed jets of fluid inwardly into the exhaust plume;
• a pulsed jet fluid supply for supplying fluid to the pulsed jet nozzles;
• and
• a pulse generator connected between the pulsed jet fluid supply and the pulsed jet nozzles, the pulse generator being operable to supply periodic first pulses of fluid to the first pulsed jet nozzle and periodic second pulses of fluid to the second pulsed jet nozzle such that the first and second pulses are out of phase with each other.

An active flow control apparatus for enhancing mixing of a nozzle exhaust plume downstream of an exit plane of a primary nozzle, comprising:

• at least first and second pulsed jet nozzles circumferentially spaced apart near a radially outermost boundary of the exhaust plume, the pulsed jet nozzles being constructed and arranged to direct pulsed jets of fluid inwardly into the exhaust plume;
• a pulsed jet fluid supply for supplying fluid to the pulsed jet nozzles;
• a pulse generator connected between the pulsed jet fluid supply and the pulsed jet nozzles, the pulse generator being operable to supply periodic first pulses of fluid to the first pulsed jet nozzle and periodic second pulses of fluid to the second pulsed jet nozzle such that the first and second pulses are out of phase with each other;
• and
• a shut-off valve coupled between the fluid supply and the pulse generator.

An aircraft jet engine having an actively controlled nozzle, comprising:

• a compressive section operable to compress air ingested by the engine, a combustion section operable to mix at least part of the compressed air with fuel and burn the mixture to produce hot combustion gases, and a turbine section operable to expand the hot combustion gases and to drive the compressive section;
• an exhaust nozzle arranged to receive expanded hot combustion gases from the turbine section and operable to exhaust the expanded hot combustion gases out a rear end of the engine to create an exhaust plume;
• at least first and second pulsed jet nozzles circumferentially spaced apart near a radially outermost boundary of the exhaust plume, the pulsed jet nozzles being constructed and arranged to direct pulsed jets of fluid inwardly into the exhaust plume;
• a bleed conduit coupled with the compressive section for bleeding a portion of the compressed air therefrom;
• and
• a pulse generator arranged to receive bleed air from the bleed conduit, the pulse generator being operable to supply periodic first pulses of air to the first pulsed jet nozzle and periodic second pulses of air to the second pulsed jet nozzle such that the first and second pulses are out of phase with each other.

An aircraft jet engine having an actively controlled nozzle, comprising:

• a compressive section operable to compress air ingested by the engine, a combustion section operable to mix at least part of the compressed air with fuel and burn the mixture to produce hot combustion gases, and a turbine section operable to expand the hot combustion gases and to drive the compressive section;
• an exhaust nozzle arranged to receive expanded hot combustion gases from the turbine section and operable to exhaust the expanded hot combustion gases out a rear end of the engine to create an exhaust plume;
• at least first and second pulsed jet nozzles circumferentially spaced apart near a radially outermost boundary of the exhaust plume, the pulsed jet nozzles being constructed and arranged to direct pulsed jets of fluid inwardly into the exhaust plume;
• a bleed conduit coupled with the compressive section for bleeding a portion of the compressed air therefrom;
• a pulse generator arranged to receive bleed air from the bleed conduit, the pulse generator being operable to supply periodic first pulses of air to the first pulsed jet nozzle and periodic second pulses of air to the second pulsed jet nozzle such that the first and second pulses are out of phase with each other;
• and
• a shut-off valve disposed between the bleed conduit and the pulse generator for interrupting supply of bleed air to the pulse generator.