• Title/Summary/Keyword: 공기가 채워진 원통

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High Frequency Scattering from Cylindrical Scatterer (원통형 산란체의 고주파 산란 특성)

  • Kim Kitaek;Yoon Kwan-Seob;La Hyoungsul;Na Jungyul
    • The Journal of the Acoustical Society of Korea
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    • v.24 no.8
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    • pp.441-446
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    • 2005
  • This paper presents the changes of acoustic scattering pattern from a single cylinder and two identical cylinders in both theoretical calculations and experimental measurements. Bi-static scattering pattern by single cylinder and two parallel cylinders (length 2m, radius 30mm) was measured in $5m\times5m\times5m$ water tank using high frequency projector (120 kHz) and hydrophone. The results show similar agreement between experiment and theory. In case of single cylinder scattering. omni-directional pattern was observed in backward but there are fluctuations or target strength in forward. Interference between each cylinder's scattering fields produce fluctuations of target strength in all directions of two cylinders.

Numerical Study on Draining from Cylindrical Tank Using Stepped Drain Port (계단형 배수구를 가진 원통 용기에서의 배수 과정에 관한 수치해석 연구)

  • Son, Jong Hyeon;Park, Il Seouk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.12
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    • pp.1043-1050
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    • 2014
  • An air-core vortex is generated during draining after stirring a rotating cylindrical tank or after filling it with water. The formation of the air-core vortex and the time of its formation are dependent on drain conditions such as the dimensions of the tank, the initial rotation or stirring speed, and the shape of the drain port. In this study, a draining process using a two-stage drain port was numerically investigated. The length and radius of the first drain stage located in the lower part of the drain port were kept constant, whereas the radius of the second drain stage was varied for simulating the draining process. The simulation was conducted by considering an axisymmetric swirling flow for all cases. The declining water level was monitored by an interface capturing method. Further, the effects of the radius of the second drain stage on the time of formation of the air-core vortex and the internal flow structure were investigated.