| 摘要 |
PROBLEM TO BE SOLVED: To effectively attenuate a sound wave propagating through a tubular body which is equipped with a plurality of shielding plates, particularly, to effectively reduce a microbarometric wave generated at an outlet by having a high-speed movable body plunge into the tubular body. SOLUTION: A passage part, which is elongated in the axial direction of the tubular body, is provided inside the tubular body; a plurality of shielding plates for shielding the sound wave are each provided in an area, avoiding the passage part in the tubular body, at predetermined intervals in the axial direction of the tubular body in such a manner as to be almost orthogonal to the axial direction of the tubular body; and a sound absorbing material is provided on the front side, facing the traveling direction of the sound wave, of the shielding plates. Additionally, the sound absorbing material is provided on both the front side of the shielding plate and the backside thereof on the other side of the front side. This enables the sound wave to be attenuated by absorbing the energy of the sound wave incident on the front side of the shielding plate or both the sides thereof, and enables the effective attenuation of the sound wave propagating through the tubular body. COPYRIGHT: (C)2006,JPO&NCIPI
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