減衰の影響を考慮したスリット状膨張空洞の消音効果の定量評価

概要

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A duct expansion, which has short axial length, acts as a resonator muffler. Generally, its property can be estimated by the numerical calculation which neglects sound damping in the expansion. But in the case of a slit, which is a duct expansion with very short axial length, the influence of sound damping is not negligible. Hence, in this paper, in order to consider sound damping, the slit was treated as a equivalent single-degree-of-freedom mechanical system. The equation to calculate the transmission coefficient of the slit Using this system was derived. By comparison between the solution of this equation and the measured value of transmission coefficient, the equivalent mass, damping coefficient and stiffness of the slit was obtained. It was found that each of these equivalent coefficients can be normalized as a almost fixed value by the slit size. Therefore the quantitative estimate of the slit property was established.
社団法人日本機械学会の論文
1998-06-25