Applied Research Laboratories, The University of Texas at Austin, Austin, Texas 78713-8029, USA.
J Acoust Soc Am. 2011 Nov;130(5):3325-32. doi: 10.1121/1.3626160.
The efficacy of large tethered encapsulated gas bubbles for the mitigation of low frequency underwater noise was investigated with an acoustic resonator technique. Tethered latex balloons were used as the bubbles, which had radii of approximately 5 cm. Phase speeds were inferred from the resonances of a water and balloon-filled waveguide approximately 1.8 m in length. The Commander and Prosperetti effective-medium model [J. Acoust. Soc. Am. 85, 732-746 (1989)] quantitatively described the observed dispersion from well below to just below the individual bubble resonance frequency, and it qualitatively predicted the frequency range of high attenuation for void fractions between 2% and 5% for collections of stationary balloons within the waveguide. A finite-element model was used to investigate the sensitivity of the waveguide resonance frequencies, and hence the inferred phase speeds, to changes in individual bubble size and position. The results indicate that large tethered encapsulated bubbles could be used mitigate low frequency underwater noise and that the Commander and Prosperetti model would be useful in the design of such a system.
采用声学共振技术研究了大的束缚密封气泡在减轻低频水下噪声方面的效果。使用直径约为 5 厘米的乳胶气球作为气泡。通过对大约 1.8 米长的充水和充气球的波导的共振，推断出相速度。指挥官和普罗斯佩里蒂有效媒质模型[J.声学学会学报 85, 732-746 (1989)]定量描述了从远低于单个气泡共振频率到略低于单个气泡共振频率的观察到的色散，并且定性地预测了在波导内静止气球集合中，空隙率在 2%到 5%之间的高衰减频率范围。有限元模型用于研究波导共振频率（因此推断出的相速度）对单个气泡大小和位置变化的敏感性。结果表明，大的束缚密封气泡可用于减轻低频水下噪声，并且指挥官和普罗斯佩里蒂模型将有助于此类系统的设计。
