| 摘要 |
<p>1516697 Noise-suppressing ducts GENERAL ELECTRIC CO 27 Aug 1975 [3 Sept 1974] 35349/75 Headings F1C F1G and F1J A noise-suppressing duct has rotating mechanical equipment disposed therein comprising first-stage rotor and stator blades which interact to generate spinning mode acoustic pressure fields with propagating and attenuating type modes, the duct being longitudinally extending and having attached to the inner surface an acoustic lining comprising a first set of peripherally spaced, longitudinally extending strips of sound absorbing material, the strips being narrow in the peripheral direction and the number exceeding the number of first stage rotor blades; and a second set of peripherally spaced, longitudinally extending strips of sound absorbing material mounted flush with the first set of strips and located between pairs of strips of the first set. The two sets of strips are effective to achieve scattering of the spinning mode acoustic pressure field.</p> |
