Abstract
A new method is proposed for investigating the propagation characteristics of a sound wave and a sound source in a flow. This is achieved by measuring the static pressure fluctuation in a flow using a lock-in-amplifier. The static pressure fluctuation in a flow is measured by using a very small static pressure probe consisting of a thin pressure tube with 8 static holes on its wall and a 0.1-in microphone set into the flare of the probe connected to the tube. The present method is found to accurately identify the propagation direction of the sound in a flow. It also detects two types of different sound sources that originate from the Karman vortex streets behind a cylinder and holes installed in it.
