| 摘要 |
PROBLEM TO BE SOLVED: To change the direction of noise reflected in a duct, without exposing aerodynamic performance of the duct to a danger, without adding inconvenient weight, cost and complexity. SOLUTION: A fluid processing duct such as an intake duct 20 of a turbine engine, has a face sheet 34 and an acoustic liner 32 having a back wall 38 separate in the horizontal direction from the face sheet. The back wall is offset from the face sheet in the nonuniform depth D to turn a sound wave incident there in the predetermined direction to the face sheet. In one embodiment, the back wall is composed of a lamp. In another embodiment, the back wall is composed of a series of stages offset from the face sheet in the different depth. The nonuniform depth of the back wall can be adapted to adjust the direction of a noise signal reflected from there, and can thereby reduce noise propagating to a surrounding environment from the duct. COPYRIGHT: (C)2006,JPO&NCIPI
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