初始涡的结构与尺度对涡旋自组织影响的研究

INFLUENCES OF THE INITIAL STRUCTURE AND SCALE ON THE SELF-ORGANIZATION OF VORTICES

在涡旋自组织动力学的框架内,实施了9组积分时间为72 h的试验,分析初始涡廓线与初始涡尺度对多涡自组织的作用。试验的初始场上,存在着12个大小不等的β和γ中尺度的涡。若初始涡廓线为高斯型,则这些涡不能自组织形成一个α中尺度的涡;若初始涡廓线为双正弦型、抛物线型或压缩型,则这个α中尺度的涡可以形成。此外,涡廓线不同,三涡流型出现的时间迟早不一,较大尺度α中尺度涡出现的时间也迟早不一。同时,初始涡的半径大小也是影响自组织过程成败的一个重要因素。

In the framework of vortex self-organization dynamics, 9 groups of numerical experiments were carried out for 72 h to investigate the influence of the structure and scale of initial vortices on the self-organization process. Initially, there were 12 meso-β or -γ scale vortices of different scales in the experiments. By analyzing the influence of six types of initial vortex profiles and scales on the self-organization process of the vortices, we reach a conclusion that the vortices with a Gaussian initial vorticity distribution couldn＇t merge into a meso-α scale vortex by self-organization, while a meso-α scale vortex was formed in the experiments with a initial vorticity distribution of double-sine, parabolic, or compressive pattern. Furthermore, the initial vortex structure also affected the timing of the genesis of tri-vortex flow pattern, and thus the timing of the formation of meso-α scale vortex. And meanwhile, the spatial scale of the initial vortex was also a significant factor determining the success or failure of self-organization.