An acoustic attenuation structure for a gas turbine engine includes a periodic structure having a first unit cell, the first unit cell having a first central body and a first axial tube disposed on the first central body and a second axial tube disposed on the first central body, opposite the first axial tube, each of the first axial tube and the second axial tube being in fluid communication with one another through the first central body.

The invention relates to acoustic management, on an aircraft turbomachine (3,12) or on a nacelle (1,10), via a panel (30,32). On a support (38) is reserved a recess (34), recessed with respect to a surrounding general surface (36) for contact with moving air. The recess (34) is adapted to receive the panel, as another so-called surface for contact with moving air. The support (38) and/or the panel comprise removable connecting elements for, in the recess (34), mounting it removably with respect to the support, the panel being an acoustic panel or a non-acoustic panel.

An acoustic absorption structure comprising a plurality of resonators. Each resonator comprises a first chamber which has a first mouthpiece delimited by an edge pressed against an inner surface of a porous zone of a skin so that the first chamber and the skin delimit a first cavity, a second chamber, in which is positioned the first chamber, which delimits, with the first chamber, a second cavity, at least one acoustic orifice passing through the first chamber, at least one drainage orifice passing through the first chamber and at least one drainage hole passing the second chamber, each drainage orifice and each drainage hole being configured to limit an accumulation of fluid in the resonator. Also, an aircraft propulsive assembly or an aircraft comprising the acoustic absorption structure are provided.

An internal structure of a primary exhaust duct of a turbomachine, the internal structure comprising a primary wall comprising a surface of revolution about a longitudinal axis, allowing the air to pass through orifices and forming an internal surface of the primary exhaust duct, an interior skin comprising a surface of revolution about the longitudinal axis, arranged inside the primary wall, an upstream flange and a downstream flange which attach the interior skin to the interior of the primary wall, at least one separator which is attached to the interior skin and which extends from the interior skin towards the primary wall, the, or each, separator extends in a plane generally parallel to the longitudinal axis, between the two flanges, and the, or each, separator is not attached to the primary wall.

An acoustic panel is provided that includes a perforated first skin, a second skin and a core. The core includes a first wall, a second wall and a stiffener. The core forms a plurality of cavities that extend vertically between the perforated first skin and the second skin and that extend laterally between the first wall and the second wall. The plurality of cavities include a first cavity. The stiffener projects partially into the first cavity and is connect to the first wall and the second wall.

A method for manufacturing a mechanical reducer for an aircraft turbomachine including a central pinion, an outer crown, N planet pinions, where N≥3, each planet pinion including a first stage meshing with the central pinion, and a second stage meshing with the outer crown, the method including the assembly marking, wherein N teeth of the central pinion are marked, and N pairs of teeth of the first stage of each planet pinion are marked, the N planet pinions each being marked identically, and the assembly of the mechanical reducer, so that the teeth of the pairs of marked teeth of the first stage of each planet pinion are disposed on either side of a marked tooth of the central pinion.

Certain aspects of the present disclosure provide a nacelle for an engine, including a plurality of acoustic fairing assemblies disposed within an aft fan duct of the nacelle, wherein each acoustic fairing assembly of the plurality of acoustic fairing assemblies comprises: a fairing body comprising a plurality of acoustic cells; and a fairing face sheet comprising a plurality of perforations and configured to be attached to the fairing body.

A sound attenuating cell includes a first sound attenuating cavity defined between a first sidewall and a second sidewall. The first sidewall is opposite the second sidewall. The first sidewall includes a first undulating surface and the second sidewall includes a second undulating surface. A deflector is coupled to the first undulating surface. The deflector extends from the first undulating surface toward the second undulating surface. The first undulating surface is axially offset from the second undulating surface to define a tortuous path between the first sidewall and the second sidewall. The first sound attenuating cavity has a first end and a second end. The first end is opposite the second end, and an inlet and an outlet of the first sound attenuating cavity is defined at the first end. The sound attenuating cell includes a second sound attenuating cavity nested within the first sound attenuating cavity.

An acoustic panel system is provided that includes a perforated first skin, a second skin and a core. The core is connected to the perforated first skin and the second skin. The core includes a plurality of chambers and a first constriction. Each of the chambers extends vertically through the core between the perforated first skin and the second skin. The chambers include a first chamber. The first constriction is configured to divide the first chamber into a plurality of fluidly coupled sub-chambers. The first constriction is configured from or otherwise includes a shape memory material.

An acoustic treatment panel includes at least one acoustically resistive layer, a reflective layer and at least one cellular structure interposed between the acoustically resistive layer and the reflective layer. The cellular structure includes cylindrical and identical main tubes which are closed at one end by the acoustically resistive layer and at the other end by the reflective layer, spacer zones between the main tubes, the spacer zones being sealed relative to one another, cutouts made at an end of certain main tubes, in contact with the reflective layer, and/or secondary tubes positioned in the main tubes and/or in the spacer zones, the cutouts and/or the secondary tubes being configured to generate acoustic cells of different dimensions from identical main tubes.