| 摘要 |
PROBLEM TO BE SOLVED: To absorb a sound more efficiently than a sound absorber using only resonance in a sound absorber using resonance. SOLUTION: In the sound absorber 1, loops of a sound pressure amplitude of a standing wave appear in a position of an end face 13 and in a position separated byλ/2 from the end face, in the first internal space 15, whereλrepresents a wavelength of an absorbing sound, and nodes of the sound pressure amplitude appear in a position of an opening end 11 and in a position separated byλ/4 from the end face 13. The loops of the sound pressure amplitude of the standing wave appear in a position of an end face 23, in a position separated byλ/2 from the end face 23, and in a position separated byλfrom the end face 23, in the second internal space 25, and the nodes of the sound pressure amplitude appear in a position of an opening end 21, in a position separated byλ/4 from the end face 23, and in a position separated by 3λ/4 from the end face 23. A pressure difference is generated between the first internal space 15 and the second internal space 25, since a position of the end face 13 is shifted byλ/4 horizontal-directionally from a position of the end face 23, a vibration part 30 is oscillated thereby, and acoustic energy is consumed to absorb efficiently the sound. COPYRIGHT: (C)2009,JPO&INPIT
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