A cascade for a thrust reversal device intended to be mounted on a turbomachine of an aircraft, the cascade including first partitions extending in a first direction, second fixed partitions extending in a second direction orthogonal to the first direction, and a frame inside which the first and second partitions extend, the frame including at least two fixed walls extending according to the first direction, and at least one part of each first partition extending between two second partitions. At least one first partition is mobile according to the second direction between a first position wherein the first partition is distant, in the second direction, from the fixed walls to form a plurality of resonating cavities with the first partitions and/or the fixed walls, and a second position wherein the one first partition is in contact with a fixed wall or another first partition.

A cascade for a thrust reversal device intended to be mounted on a turbomachine of an aircraft, the cascade including first partitions extending in a first direction, second fixed partitions extending in a second direction orthogonal to the first direction, and a frame inside which the first and second partitions extend, the frame including at least two fixed walls extending according to the first direction, and at least one part of each first partition extending between two second partitions. At least one first partition is mobile according to the second direction between a first position wherein the first partition is distant, in the second direction, from the fixed walls to form a plurality of resonating cavities with the first partitions and/or the fixed walls, and a second position wherein the one first partition is in contact with a fixed wall or another first partition.

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.

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.

An acoustic attenuation panel for a propulsion assembly includes an acoustic front skin having perforations, and a central structure formed from partitions arranged perpendicularly in order to make up cells, wherein the front skin and the central structure form the panel which is made as a single piece and is provided for directly covering a surface of an element of the propulsion assembly forming a rear skin which closes the cells of the central structure at the rear.

An acoustic attenuation panel for a propulsion assembly includes an acoustic front skin having perforations, and a central structure formed from partitions arranged perpendicularly in order to make up cells, wherein the front skin and the central structure form the panel which is made as a single piece and is provided for directly covering a surface of an element of the propulsion assembly forming a rear skin which closes the cells of the central structure at the rear.

A noise attenuation panel for a structure within a propulsion system includes a first plurality of unit cells; and a second plurality of unit cells, the second plurality of unit cells merged within the first plurality of unit cells, the first plurality of unit cells including a first periodic structure having a first unit cell, a second unit cell, a third unit cell and a fourth unit cell, each of the first unit cell, the second unit cell, the third unit cell and the fourth unit cell including a central body interconnected via a plurality of lateral tubes extending from the central body, the first periodic structure forming a first lateral layer of unit cells.

A noise attenuation panel for a structure within a propulsion system includes a first plurality of unit cells; and a second plurality of unit cells, the second plurality of unit cells merged within the first plurality of unit cells, the first plurality of unit cells including a first periodic structure having a first unit cell, a second unit cell, a third unit cell and a fourth unit cell, each of the first unit cell, the second unit cell, the third unit cell and the fourth unit cell including a central body interconnected via a plurality of lateral tubes extending from the central body, the first periodic structure forming a first lateral layer of unit cells.

A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.

A gas turbine engine generates noise during use, and one particularly important flight condition for noise generation is take-off. A gas turbine engine that has high efficiency provides low noise, in particular from the fan and the turbine that drives the fan. Values are defined for a noise parameter NP that results in a gas turbine engine having reduced combined fan and turbine noise.