The acoustics of bubbles and bubbly assemblages: a suite of laboratory studies

The in situ study of oceanic bubble acoustics is a challenging endeavor. One must impose a variety of a priori assumptions and constraints in order to extract information that unambiguously sheds light on the underlying physical mechanisms that govern the transmission and scattering of sound in oceanic bubble assemblages. Conversely, laboratory studies afford an added measure of physical control and observational access that permits one to focus on certain facets of bubble activity with accuracy and precision. We provide an overview of several laboratory-based bubble acoustics studies under way at Boston University. The scope of the work spans the spectrum from the quantitative measurement of acoustic dispersion through, and scattering from, high void fraction bubbly regions, to detailed studies of the linear dynamics of individual bubbles. [Work supported by ONR.]