Scattering and Absorption of Sound by Gas Bubbles in Water

Abstract

Gas bubbles in sea water are most efficient sound scatterers. This is due to the fact that in a wide frequency range this scattering is of a resonance nature. The resonance scattering cross-section of an air bubble near the water surface, for example, is approximately 103 times its geometrical cross-section. The resonance bubbles not only scatter but absorb the acoustic energy, as well. Furthermore, at sufficiently high concentrations they markedly change the compressibility of water and, consequently, the sound velocity which appears to depend on the sound frequency.