シュリーレン法を用いた気柱振動発生後における開口端近傍の音場観察―開口端反射の本質追究の一環として―

抄録

Although the reflection of the air column vibration at the open end of a tube is considered to be an important process for the resonance of the air column, the mechanism of the reflection is not fully understood. In a previous study conducted by the authors, the air column vibration was visualized by computer simulation, and concentric waves were seen propagating from the corner part of the open end, which is supposed to be related to the mechanism of the reflection. In the present study, a direct observation of the reflection was attempted in order to confirm the validity of the computer simulation. Specifically, optical observation of the sound field around the open end on vibrating the air column was performed using the Schlieren method. As a result, the concentric waves formed at the corner part of the open end were shown in the Schlieren images. According to this study, the findings derived from the computer simulation has been supported by Schlieren images and it is suggested that the Schlieren method could be an effective way to study the reflection of the air column vibration at the open end of a tube.