Abstract: A noise-attenuating covering configured for example for a pipe for guiding gases along a gas path. The covering includes a wall defining the gas path and at least one resonance cavity, the wall being pierced with holes for fluid communication between the gas path and the resonance cavity to attenuate noise. The holes have substantially identical diameters and, since the pipe is arranged to guide the gases in the downstream direction, a number of the openings per wall surface unit decreases continuously along the gas path in the downstream direction, such as to confer on the wall substantially constant acoustic resistance along the gas path, for which the noise attenuation is optimized along the gas path.

Abstract: A noise-attenuating covering configured for example for a pipe for guiding gases along a gas path. The covering includes a wall defining the gas path and at least one resonance cavity, the wall being pierced with holes for fluid communication between the gas path and the resonance cavity to attenuate noise. The holes have substantially identical diameters and, since the pipe is arranged to guide the gases in the downstream direction, a number of the openings per wall surface unit decreases continuously along the gas path in the downstream direction, such as to confer on the wall substantially constant acoustic resistance along the gas path, for which the noise attenuation is optimized along the gas path.

Abstract: A device for ejecting gas from a gas turbine engine, which includes: an outer wall and an inner wall defining a gas flow path therebetween, the inner wall forming a central body defining an inner cavity, the outer wall being perforated and communicating with at least one outer resonance cavity for attenuating noise in a first range of sound frequencies; and a mechanism for placing the outer and inner cavities in fluid communication, extending through the gas flow path, the inner cavity thus forming a resonance cavity for attenuating the noise in a second range of sound frequencies. The device can, for example, be used to attenuate two ranges of sound frequencies.

Abstract: A gas turbine engine, in which gases flow upstream to downstream, including a combustion chamber, a high-pressure turbine placed downstream from the combustion chamber, arranged so as to receive combustion gases from the combustion chamber, a free turbine, and an exhaust-gas guide cone attached to the free turbine downstream from the free turbine, the turbine engine emitting sound waves during operation. The guide cone includes a sound suppressor, for example with a Helmholtz resonator structure, with a resonant cavity and a resonator neck in communication with an opening, arranged so as to suppress the sound waves emitted by the turbine engine.