• Title/Summary/Keyword: Rayleigh 제트 불안정모델

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An empirical model of air bubble size for the application to air masker (에어마스커의 기포크기 추정 경험적 모델)

  • Park, Cheolsoo;Jeong, So Won;Kim, Gun Do;Park, Youngha;Moon, Ilsung;Yim, Geuntae
    • The Journal of the Acoustical Society of Korea
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    • v.40 no.4
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    • pp.320-329
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    • 2021
  • In this paper, an empirical model of air bubble size to be applied to an air masker for reduction of underwater radiation noise is presented. The proposed model improves the divergence problem under the low-speed flow condition of the existing model derived using Rayleigh's jet instability model and simple continuity condition by introducing a jet flow velocity of air. The jet flow velocity of air is estimated using the bubble size where the liquid is quiescent. In a medium without flow, the size of the bubble is estimated by an empirical method where bubble formation regime is divided into a laminar-flow range, a transition range, and a turbulent-flow range based on the Reynolds number of the injected air. The proposed bubble size model is confirmed to be in good agreement with the Computational Fluid Dynamics (CFD) analysis result and the experimental results of the existing literature. Using the acoustic inversion method, the air bubble population is estimated from the insertion loss measured during the air injection experiment of the air- masker model in a large cavitation tunnel. The results of the experiments and the bubble size model are compared in the paper.