심해 풍파 난류 경계층에서의 와 구조

Abstract

The results of experimental investigation of vortical structures in the turbulent boundary layer of deepwater wind waves are presented. With the help of relatively high-speed PIV system, subsurface velocity field of wind waves were observed and vortical structures in the flow field were visualized. Through the qualitative examination of the vortical structures, it was found that a coherent vortex is formed right underneath the wave crest and traveled in phase with the wave. The coherent vortex rotated counter-clockwise for most of the cases, but clockwise vortex was observed when apparent wave breaking occurred at the wave crest. In the near-surface region, complex vortex-vortex interactions were observed according to the traveling of the coherent vortex, whereas vortical structures far below the water surface moved little due to weak influence of the surface waves.