Transactions of the Korean Society for Noise and Vibration Engineering (한국소음진동공학회논문집)

The Korean Society for Noise and Vibration Engineering (한국소음진동공학회)
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Investigation on Shapes and Acoustic Characteristics of Air Bubbles Generated by an Underwater Nozzle

수중 노즐에서 발생하는 기포의 형상 및 음향 특성 연구

  • 김종철 (국방과학연구소 제2체계개발본부) ;
  • 오준석 (국방과학연구소 제2체계개발본부) ;
  • 조대승 (부산대학교 조선해양공학과)
  • Published : 2006.02.01
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Abstract

It is well known that the acoustic characteristics of the sea are significantly affected by bubbles which have their own inherent characteristics at the undersea. In this study, the shape and acoustic characteristics of air bubbles generated by an underwater nozzle are calculated numerically, and are measured with a high speed camera and a hydrophone at various air flow rates in the experimental apparatus. As a result of analysis, the shape calculated numerically well matched with measured values at low flow rates, but in case of relatively higher flow rates. the use of correction coefficient is needed for more accurate estimation of the bubble shape. And also the rising velocity of a single bubble is constant regardless of both the bubble size and the flow rate. and the acoustic signal generated when the bubble is produced by an underwater nozzle has the same characteristic of natural frequency of the bubble pulsation, and is agreed with Minnaert's equation if the correction coefficient is considered in accordance with the flow rate.

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References

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