Numerical Study of Coherent Vortex in Late Wake Downstream of a Sphere in Weakly Stratified Fluid

잔류내 응집 와류의 수치 해석

  • 이승수 (충북대학교 구조시스템공학과) ;
  • 이영규 (충북대학교 구조시스템공학과 대학원) ;
  • 양경수 (인하대학교 기계공학과)
  • Published : 2003.04.23

Abstract

Decades of studies of geophysical flow have unveiled that the flow downstream of obstacles in stratified flow consists of attached wake and strong internal 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 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 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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