Abstract
A new technique for measurement of two-dimensional acoustic field near the sound source is developed instead of using microphone. A distribution of vibration velocity on a film due to acoustic wave can be acquired as a distribution of normal particle velocity by means of laser Doppler vibrometer which has scanning mirrors. This proposed technique is advantageous to the measurement of an arbitrary angle with a target source, as compared with using microphones. In the previous investigation, it is found that a boundary condition leads to fluctuation of a vibration velocity distribution around the boundary. It is supposed that a reflection of travelling wave on the film causes at the boundary. In this report, an analysis for this problem is developed, and a method to reduce the fluctuation is discussed.
