3個のマイクロフォンを用いた音響特性計測法の開発 : エンジン吸気配管系と吸音材料への適用(機械力学,計測,自動制御)

概要

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A measuring method for the transfer matrix parameters of acoustic systems by using 3-microphones is described in this report. The acoustic characteristics of engine intake systems are usually analyzed by the transfer matrix method. However, there are some intake subsystems for which there is still no adequate theoretical representation. By using the 3-microphones method, the matrix parameters of unknown systems can be determined experimentally. The matrix parameters of an air cleaner were measured and used to predict the acoustic characteristics of the intake systems. The comparisons were made between predicted results using the matrix parameters and directly measured results with mean flow. Agreement in fairly good and it suggests that this method can be used to evaluate the acoustic characteristics of intake systems with low speed mean flow. Furthermore, this 3-microphones method was applied for measurement of the acoustic characteristics of sound absorbing materials. The propagation constants and the characteristic impedance of some materials were measured and compared with measured values by using the 2-microphones method. The good agreement suggests that this method is also reliable to measure the acoustic characteristics of sound absorbing materials.
一般社団法人日本機械学会の論文
2002-02-25