Acoustic absorption structure comprising a cellular structure and at least one partition tube which has at least two flat sides which are connected to the walls of the cellular structure

An acoustic absorption structure comprising:

• at least one cellular structure interposed between an acoustically resistive layer and a reflective layer;
• the cellular structure comprising a first face in contact with the acoustically resistive layer, a second face in contact with the reflective layer and a plurality of cells, each leading to a region of the first and second faces, and each cell being delimited by walls;
• the cellular structure comprising at least one partition tube positioned in one of the cells and comprising a first tube section which extends between first and second ends and has a first section between the first and second ends, and a second tube section which extends between the first and second ends and has a second section between the first and second ends;
• the second section being smaller than the first section and a joining wall connecting the second ends of the first and second tube sections;
• the first end of the first tube section being sealed by a first layer, from either the acoustically resistive layer or the reflective layer, and the first end of the second tube section being spaced apart from a second layer, which is different from the first layer, from either the acoustically resistive layer or the reflective layer;
• the first tube section of the partition tube comprising at least two flat sides and at least one lateral wall, the walls which delimit the cell into which the partition tube is inserted comprising at least first and second planar fixing walls against which the flat sides of the partition tube are placed and fixed, and at least two remote walls which are spaced apart from the lateral wall of the partition tube.