A215 回転乱流中の渦構造とレイノルズストレス

概要

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Vortical structures in uniformly sheared turbulent flow in the rotating co-ordinate system are investigated theoretically based upon the data by direct numerical simulations. The generation and maintaining mechanisms of long-lived longitudinal vortical structures are considered in zero-absolute-vorticity system when the mean shear Rossby number Ro^<(S)>=-1. It is found that they initially grow from random turbulent field under the action of the Coriolis force with their directions to that of background shear vortieity. As time goes on, they are maintained by the combined effects of the Coriolis force and a swirling motion of the vortex tube. Distribution of the Reynolds stress around the coherent vortical structure is studied and it is found that the Reynolds stress plays an important role to create and maintain the structure.
2002-07-23