ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

2pAO2. Direct numerical simulation of the acoustic behavior of bubble clouds.

M. Watanabe

A. Prosperetti

Dept. of Mech. Eng., Johns Hopkins Univ., Baltimore, MD 21218

The description of a bubble assembly, or cloud, by means of an ``effective medium'' approximation has found widespread application in the underwater acoustics community. In this approach the bubbly liquid is regarded as a continuum endowed with properties different from those of the pure liquid. In this study the effective medium results are compared with those of a direct numerical simulation in which the effects of the mutual interaction of the bubbles are simulated. A spherical assembly of bubbles immersed in an incompressible liquid is studied. The potential problem is solved numerically with a singularity expansion method including both volume pulsations and translational oscillations of the bubbles. Numerical results for both single realizations and ensemble averages are presented and discussed. [Work supported by the Office of Naval Research.]