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Published on: May 9, 2021
Influence of distribution parameters on acoustic radiation from bubble clusters
Fuqiang Deng1, Lingxin Zhang1, Peng Wang1
1State Key Laboratory of Fluid Power and Mechatronic Systems, Department of Engineering Mechanics, Zhejiang University, Hangzhou 310027, China.
Direct numerical simulation reveals bubble cluster collapse times are similar, regardless of bubble size or position. Layered bubble arrangements produce multiple sound pulses, unlike random arrangements which emit a single pulse.
Area of Science:
- Underwater acoustics
- Fluid dynamics
- Acoustic cavitation
Background:
- Cavitation noise is a significant underwater acoustic issue.
- Understanding acoustic radiation from bubble clusters is key to cavitation noise mechanisms.
Purpose of the Study:
- Investigate the acoustic radiation and collapse dynamics of bubble clusters.
- Compare bubble cluster behavior to an equivalent single bubble.
Main Methods:
- Direct numerical simulation (DNS) for bubble clusters (20-40% volume fraction).
- Ffowcs Williams-Hawkings (FW-H) method for far-field sound pressure calculation.
- Analysis of varying bubble sizes and position distributions.
Main Results:
- Bubble cluster collapse times are identical for a given volume fraction, irrespective of bubble size or distribution.
- Layered bubble arrangements lead to layer-by-layer collapse and multiple sound pulses.
- Random arrangements and varying bubble sizes have minimal impact on acoustic radiation patterns, similar to equivalent bubbles.
Conclusions:
- Bubble cluster collapse dynamics are primarily governed by volume fraction.
- Acoustic radiation patterns are strongly influenced by bubble arrangement, with layered structures producing distinct multi-pulse emissions.
- Sound pressure levels in the frequency domain converge for bubble clusters with >25% volumetric fraction, closely matching equivalent bubbles.
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