Abstract:

Acoustic techniques used for determining bubble distributions can be limited because a solution to an ill-conditioned inverse problem is required. Examining cases in which closed-form solutions are possible, however, may give us insight about the inverse procedure. In a previous ASA meeting [Goodman, Caruthers, and Elmore, ``Dispersion estimates for bubbly seawater,'' J. Acoust. Soc. Am. 100, 3196(A) (1997)], exact solutions for dispersion for the inverse procedure in special cases of bubble distributions were explored. Here some of those special cases are examined in terms of how they apply to attenuation measurements. For cases in which the closed-form solution are not possible, the resonant bubble approximation allows for estimating the bubble population from attenuation measurements. This paper shows that there is observable error in this procedure, but that the error can be reduced by application of an iterative procedure discussed here. [Work supported by ONR.]