Journal of the Society of Naval Architects of Korea (대한조선학회논문집)

The Society of Naval Architects of Korea (대한조선학회)
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Formation of Coherent Vortices in Late Wake Downstream of an Object in Weakly Stratified Fluid

약한 밀도 층상류에서 발생하는 물체 후류의 잔류와 응집 와류의 형성

  • Lee, Sung-Su (School or Civil Engineering, Chungbuk National University) ;
  • Kim, Hak-Sun (School or Civil Engineering, Chungbuk National University)
  • Received : 2010.10.19
  • Accepted : 2011.07.26
  • Published : 2011.10.20
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Abstract

Decades of studies of geophysical flow have unveiled that the flow downstream of obstacles in stratified flow consists of attached wake and strong gravity waves, or separated, fluctuating wake and persistent late wakes. Among unique and interesting characteristics of the stratified flow past obstacles is the generation of coherent vortex in the late wake far downstream of the object. Unlike in homogeneous fluid, the flow field downstream self-develops coherent vortex even after diminishing of the near wake, no matter how small the stratification is. This paper present a computational approach to simulate the generation of the coherent vortex structure in the late wake of a moving sphere submerged in weakly stratified fluid. The results are in consistent with several experimental observations and the vortex stretching mechanism is employed to explain the process of coherence.

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References

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