ABSTRACT: This paper presents the results obtained from a detailed study of the sound
field within and around a cylindrical column of bubbles generated at the center of an
experimental water tank. The bubbles were produced by forcing air through a circular array
of hypodermic needles. As they separated from the needles the “birthing wails”
produced were found to excite the column into normal modes of oscillation whose spatial
pressure-amplitude distribution could be tracked in the vertical and horizontal
directions. The frequencies of vibration were predicted from theoretical calculations
based on a collective oscillation model, and showed close agreement with the
experimentally measured values. Furthermore, absolute sound levels were analytically
calculated with the results again in agreement with the measured values. In addition to
constituting a test for the theoretical model, these findings provide considerable new
evidence to support the notion that bubble plumes can be a major source of underwater
sound around frequencies of a few hundred Hertz.
J. Acoust. Soc. Am. 95, 3171-3182, 1994
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