Comparison of Acoustic Radiation Characteristics in the Near and Far Fields Due to the Vibration of a Circular Disk Placed on an Infinite Rigid Baffle Using the Rayleigh Integral Method and Lumped Parameter Method

다국어 초록 (Multilingual Abstract)

The sound pressure measured at the near field exhibits significant fluctuation depending on the size and frequency of the sound source. Therefore, it is necessary to use the sound pressure measured or numerically calculated at a sufficient distance from a radiator to estimate the actual sound power of the source. In this study, we investigated the appropriate distance for measuring or numerically calculating the sound pressure to validly estimate the sound power of a radiator, which depends on the frequency. A theoretical estimation of the starting position of the far-field acoustic characteristics for rigid disk vibrations was conducted, and the results were numerically compared and reviewed using the Rayleigh integral method (RIM) and lumped parameter method (LPM). The analysis using these methods, with modeling based on the 1/3 wavelength rule, demonstrated accurate predictions of the near-field acoustic characteristics. It was shown that the near sound field could be accurately predicted by modeling and analyzing under the condition of the 1/3 wavelength rule using the RIM and LPM. It was found that even when elements were modeled at a larger size than the 1/3 wavelength rule, the far-field sound pressure result could effectively depict the theoretical far-field sound pressure in the case of the RIM. It was also shown that the sound pressure due to the vibration of a flexible circular disk modeled with an element size based on the 1/3 wavelength rule was well predicted by both the LPM and RIM.