Preliminary Tank Test Results on the Effects of Surface Waves in Underwater Acoustic MeasurementInduced by Airborne Sound Sources

Abstract

In order to investigate the influence of surface waves on underwater soundpropagation from an airborne source, a preliminary test was conducted in a water tank with surface wavegenerators. Sweep-sine and stepped-sine signals ranging from 500 Hz to 6 kHz were continuously emittedusing an airborne sound source array, and six hydrophones were installed underwater at equal intervalsdirectly beneath the source. Sound pressure levels were measured under both regular and irregular waveconditions, as well as in calm water for comparison. The results showed that the signal level decreased withincreasing water depth, and that the presence of waves affected the characteristics of the received signals.