Abstract: A aircraft weapons bay acoustic resonance suppression system for reducing undesirable acoustic resonances within an open weapons bay of an aircraft in flight is described. The system includes a rod mounted upon and spaced a distance from an extensible aircraft spoiler. The rod has a hollow core and includes a multiplicity of apertures axially aligned into two groups, placed at the point of fluid separation. A multiplicity of synthetic jets are received within the rod, each jet in fluid communication with a corresponding aperture. The jets combine to form first and second perturbation elements. The perturbation elements are sinusoidally driven out of phase at high frequencies by an actuator. This effectively creates a high frequency forcing of the airstream which is amplified by the airflow, creating a violent shedding. Advantageously, this violent shedding dramatically reduces acoustic resonance within the weapons bay of the aircraft.

Abstract: A high frequency pulsed fuel injector is disclosed. The fuel injector incorporates a resonance tube in outlet fluid communication with a fuel nozzle. During operation the resonance tube provides a pulsating output which is directed into the fuel nozzle. The pulsating output of the resonance tube perturbs the flow of fuel in the fuel nozzle, effectively breaking it up into discrete slugs or chunks for subsequent combustion in a combustion chamber. The combustion process is greatly enhanced by this breakup of the fuel jet, improving combustion efficiency as well as reducing undesirable emissions.

Abstract: A jet noise suppressor is disclosed. The jet noise suppressor includes first and second high frequency pulse injection units located exteriorly of the turbine engine exhaust nozzle. The pulse injection units are located oppositely, diametrically across the exhaust nozzle. The pulse injection units include a resonance tube in outlet fluid communication with an injector nozzle. High pressure gas is supplied to the resonance tubes. A second source of high pressure gas includes a switch for supplying an alternating flow of high pressure gas to the injector nozzles. The combination of the high frequency pulses emitted from the injection units with the alternating low frequency, high amplitude mode of injection across the exhaust nozzle, provides a dramatic reduction of noise as well as exhaust temperature.

Abstract: An aircraft weapons bay high frequency acoustic suppression apparatus is disclosed. The apparatus includes an extendable spoiler retractably received within an aircraft weapons bay. An injector unit is received within the spoiler for injecting high frequency pulses of pressurized gas into the airstream. The injector unit includes a resonance tube in outlet fluid communication with an nozzle. The pulsating output of the resonance tube perturbs the flow of pressurized gas in the nozzle, effectively breaking it up into discrete slugs or pulses which then exit the nozzle and enter the airstream. The high frequency perturbation of the airflow across the weapons bay, created by the aircraft weapons bay high frequency acoustic suppression apparatus of the present invention effectively suppresses undesirable acoustic resonance within the open weapons bay.

Abstract: An aircraft weapons bay acoustic suppression apparatus is disclosed. The apparatus reduces or eliminates acoustic resonance within an open cavity of an aircraft such as a weapons bay of an aircraft in flight. The apparatus includes an oscillatable spoiler plate which is extended into the airstream. At least one shaker is placed in operative engagement with the spoiler plate in order to oscillate the spoiler plate at high frequencies and high amplitudes to seed the shear layer with frequencies which directly complete with the natural frequency of the shear layer vortices. In this way, the damage arising from natural shear layer vortices can reduced or canceled within the weapons bay.

Abstract: A method and apparatus for actively enhancing aircraft weapon separation by actively modifying the flowfield characteristics of an open, shallow weapons bay during flight is disclosed. The apparatus includes a source of high pressure gas in fluid communication with an injector located on the aircraft. A control valve controls the introduction of a flow of high pressure gas from the source into the injector. The injector is placed ahead of the nose of the weapon and directs the flow of the high pressure gas externally into the airstream of the aircraft in flight. The injection of the high pressure gas into the airstream initiates a flowfield in the open weapons bay similar to that which occurs in a deep bay, encouraging a flat, even weapons separation.