Journal of Mechanical Science and Technology

  • 제14권12호
  • /
  • Pages.1386-1395
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  • 2000
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  • 1738-494X(pISSN)
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  • 1976-3824(eISSN)
대한기계학회 (The Korean Society of Mechanical Engineers)
권호 표지

Turbulent Flow Field Structure of Initially Asymmetric Jets

  • Kim, Kyung-Hoon (Collage of Mechanical and Industrial System Engineering, Institute of Laser Engineering) ;
  • Kim, Bong-Whan (Collage of Mechanical and Industrial System Engineering, Institute of Laser Engineering) ;
  • Kim, Suk-Woo (Hyundae Construction Co.)
  • 발행 : 2000.12.01
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초록

The mear field structure of round turbulent jets with initially asymmetric velocity distributions is investigated experimentally. Experiments are carried out using a constant temperature hot-wire anemometry system to measure streamwise velocity in the jets. The measurements are undertaken across the jet at various streamwise stations in a range starting from the jet exit plane and up to a downstream location of twelve diameters. The experimental results include the distributions of mean and instantaneous velocities, vorticity field, turbulence intensity, and the Reynolds shear stresses. The asymmetry of the jet exit plane was obtained by using circular cross-section pipes with a bend upstream of the exit. There pipes used here include a straight pipe, and 90 and 160 degree-bend pipes. Therefore, at the upstream of the upstream of the pipe exit, secondary flow through the bend mean streamwise velocity distribution could be controlled by changing the curvature of pipes. The jets into the atmosphere have two levels of initial velocity skewness in addition to an axisymmetric jet from a straight pipe. In case of the curved pipe, a six diameter-long straight pipe section follows the bend upstream of the exit. The Reynolds number based on the exit bulk velocity is 13,400. The results indicate that the near field structure is considerably modified by the skewness of an initial mean velocity distribution. As the skewness increases, the decay rate of mean velocity at the centerline also increases.

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참고문헌

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