Sarkar, KausikProsperetti, Andrea2020-03-102020-03-101993-06Copyright 1993 The Journal of the Acoustical Society of America. Recommended citation: Sarkar, K., and A. Prosperetti. "Backscattering of underwater noise by bubble clouds." The Journal of the Acoustical Society of America 93, no. 6 (1993): 3128-3138. DOI: 10.1121/1.405697 URL: https://asa.scitation.org/doi/abs/10.1121/1.405697 Reproduced in accordance with the original publisher’s licensing terms and with permission from the author(s).https://hdl.handle.net/10657/6089This paper is a continuation of an earlier one [Prosperetti et al., J. Acoust. Soc. Am. 93, XXX (1993)] in which the low?frequency backscattering of sound by hemispherical bubble clouds at the ocean’s surface was studied. Here, clouds of various geometrical shapes (spheroids, spherical segments, cones, cylinders, ellipsoids) are considered and results in substantial agreement with the earlier ones and with the experiments of Chapman and Harris [J. Acoust. Soc. Am. 34, 1592–1597 (1962)] are found. The implication is that the backscattering levels are not strongly dependent on the shape of the clouds, which strengthens the earlier conclusion that bubble clouds produced by breaking waves can very well be responsible for the unexpectedly high backscattering levels observed experimentally. The accuracy of the Born approximation used by others for similar problems is also examined in the light of the exact results. Significant differences are found for gas concentrations by volume of the order of 0.01% or higher. Finally, shallow nonaxisymmetric plumes are briefly considered.en-USGeodesyBorn approximationUnderwater acousticsTurbulent flowsarticle