A fairing for a power generation machine, the fairing comprising: a first layer comprising a metallic material; a second layer comprising a composite; and a third layer positioned between the first layer and the second layer, the third layer being configured to attenuate acoustic waves over a predetermined frequency range.

A structure is provided that includes a perforated first skin, a second skin and a core. The core includes a first sidewall, a second sidewall, a first baffle and a second baffle. The core forms a plurality of cavities vertically between the perforated first skin and the second skin. The first baffle is connected to the perforated first skin at a first baffle first end. The first baffle is connected to the second skin at a first baffle second end by a first moveable joint. The second baffle is connected to the perforated first skin at a second baffle first end. The second baffle is connected to the second skin at a second baffle second end. A first of the cavities extends laterally between the first sidewall and the second sidewall. The first cavity extends longitudinally between the first baffle and the second baffle.

An acoustic core may include an array of resonant cells configured as a plurality of resonant cell groups. The resonant cell groups may include a plurality of resonant cells configured as a partitioned resonant cell that include a converging resonant cell and a diverging resonant cell. The converging resonant cell and the diverging resonant cell may be defined by a plurality of cell walls integrally formed with one another and a partition integrally formed with the plurality of cell walls. The partition may at least partially delimit the converging resonant cell from the diverging resonant cell. The converging resonant cell may define an upper resonant space delimited by the partition and a top face of the array of resonant cells. The diverging resonant cell may define a lower resonant space delimited by the partition and a bottom face of the array of resonant cells.

An assembly for an aircraft turbojet engine is described. The assembly includes a central gas-exhaust element and a connecting flange interposed between, upstream, a metallic outlet of a turbojet engine and, downstream, the central element. The connecting flange consists of an annular part and flexible lugs having axially: a first end where the lug is connected to the annular part, and a second free end, projecting radially outwards from the first end and towards which the lug is fixed with the central element.

An internal structure of a primary exhaust duct of a turbomachine, which has a primary wall allowing air to pass through orifices and forming an internal surface of the primary exhaust duct, an interior skin arranged inside the primary wall, and at least one separator of which a first edge region is attached to the interior skin and which has two geometries. A change from the first geometry to the second takes place when the temperature of the separator exceeds a first temperature, and the change from the second to the first takes place when the temperature of the separator drops below a second temperature. The coefficient of expansion of the separator is greater than that of the interior skin. The variation in the geometry of the separators depending on the temperature of the engine eases assembly at ambient temperature due to the compression of the separators.

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 device for securing at least one thermal protection mat to an internal fixed structure of a nacelle includes at least one removable fastening element for securing the at least one thermal protection mat to the internal fixed structure designed to be arranged between the mat and the internal fixed structure. The device includes at least one gripping element connected to the removable fastening element to project relative to the mat on the opposite side to the internal fixed structure, the removable fastening element being intended to be detached from the internal fixed structure by a pulling force exerted on the gripping element.

A structure for the nacelle of an aircraft propulsion unit includes a first skin and stiffeners arranged to hold acoustic treatment modules against the first skin. Each acoustic treatment module includes a honeycomb core and a second skin, such that the honeycomb core is sandwiched between the first skin and the second skin. Such a structure allows the structural reinforcement function provided by the stiffeners to be separated from the acoustic treatment function performed by the acoustic treatment modules which are simply bearing on the first skin.

An acoustic absorption structure includes: at least one acoustic element which has at least one cavity delimited by at least one enclosure comprising at least one first drainage orifice passing through the enclosure, and a rotational indexing system making it possible to position the acoustic element so that at least one first drainage orifice is positioned in proximity to or at a lowest point of the cavity. An aircraft propulsion assembly including such an acoustic absorption structure is also described.

Embodiments of the invention are shown in the figures, where a nacelle cowling structure for a turbomachine having a bypass duct defining a path for an airflow is provided, the nacelle cowling structure including: an outer layer defining an external surface of the nacelle cowling structure, an inner layer defining a surface of the bypass duct, a front mounting area for fixation to the turbomachine and a rear mounting area for fixation to the turbomachine downstream the front mounting area with respect to the bypass duct flow path, wherein a space between the outer and inner layers and between the front and rear mounting areas is filled with acoustic material.