423 平面クエット乱流の渦構造(S35-1 乱流渦構造(1),S35 乱流渦構造)  [in Japanese] 423 Vortical Structures in plane Couette turbulence  [in Japanese]

Unstable periodic motions are educed by solving the Navier-Stokes equation numerically by use of Newton-Raphson iteration for Couette turbulence. It reproduces the instantaneous structures as well as the statistical characteristics of turbulence. This suggests that the turbulent state may approach frequently these periodic motions. Thus it is regarded as the fundamental spatio-temporal coherent structures or the skeleton of turbulence. In this study, we identify vortical structures by making use of sectional swirl and pressure minimum scheme to understand those dynamics in periodic motion for plane Couette turbulence. Moreover, we examine how passive particles and lines are advected and mixed in this system.