Abstract
This paper describes a method of controlling the noise radiated from multiple openings of an enclosure by appropriately arranging absorbing materials. There are two steps in the method. First, the sound pressure and acoustic particle velocity in the enclosure are calculated by numerical simulation. Next, we examine the arrangement of the absorbing materials to decrease the acoustic energy of the radiated sound from the openings based on the numerical results of the FDTD method. The numerical results show that there are peaks caused by the natural frequencies of the enclosure and the peak caused by the resonant frequency in the characteristics of sound pressure levels measured at the center of each opening. The numerical results reveal that if the absorbing materials are appropriately arranged, the sound pressure levels at the natural frequencies can be suppressed. Experimental results also show the same tendency.
