| 主权项 |
1. An aircraft comprising:
a fuselage defining outwardly-facing surfaces and lift-generating wings extending outwardly in generally opposite directions away from the fuselage and defining outer wing surfaces; at least one engine having a thrust-generating element, and wherein the aircraft includes a source of noise that produces noise during operation of the aircraft; a noise absorbing acoustic liner disposed on the outer surfaces of the fuselage and the wings, and having a depth dimension, the noise absorbing liner including:
a porous outer surface that permits a portion of noise incident on the porous surface to pass therethrough, wherein the depth dimension extends between the porous outer surface and the portion of the outer surfaces of the fuselage or wings on which the acoustic liner is disposed; anda plurality of internal chambers of different lengths interconnected by internal passageways to permit sound to travel between the internal chambers, wherein each of the plurality of internal chamber has an opening; connected to the porous outer surface, wherein each of the plurality of internal chambers, receives sound through the porous outer surface, and has a first internal surfaces defining the internal chamber, wherein each of the plurality of internal chambers includes a first portion that extends into the depth dimension of the acoustic liner away from the porous outer surface to a depth that is greater than the dimension of the opening, wherein each of the plurality of internal chambers converts a first portion of the sound that enters the internal chambers through the porous outer surface into heat energy, and transmits sound that has not been converted into the heat energy out of the internal chambers through the porous surface, and wherein each of the plurality of internal chambers contains an acoustic filler material that absorbs a second portion of the sound that enters the internal chamber. |
