Dipoles and streams in two-dimensional turbulence
Dipoles and streams in two-dimensional turbulence
复制标题
二维湍流中的偶极子和流
DOI：
10.1017/jfm.2020.769
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发表时间：
2020
影响因子：
3.7
通讯作者：
J. Jiménez
中科院分区：
文献类型：
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作者：
J. Jiménez
根据在吉梅内斯进行的蒙特卡罗实验(J·特布尔，2020年，DOI：10.1080/14685248.2020.1742918)的建议，偶极子对衰变二维湍流动力学的重要性与单个涡核一样重要，发现这种流动的动能是由偶极子串联形成的细长流携带的。漩涡分成一系列快速移动的小核心和另一系列移动缓慢的较大核心，可以说是冻结成了缓慢演化的“晶体”。这两个家族的运动学非常不同，只有前者是自相似的。后者负责流动的大部分动能，其涡旋形成偶极子和流。讨论了这种慢速组分的生长机制。
Abstract Following the suggestion from the Monte–Carlo experiments in Jiménez (J. Turbul., 2020, doi:10.1080/14685248.2020.1742918) that dipoles are as important to the dynamics of decaying two-dimensional turbulence as individual vortex cores, it is found that the kinetic energy of this flow is carried by elongated streams formed by the concatenation of dipoles. Vortices separate into a family of small fast-moving cores, and another family of larger slowly moving ones, which can be described as ‘frozen’ into a slowly evolving ‘crystal.’ The kinematics of both families are very different, and only the former is self-similar. The latter is responsible for most of the kinetic energy of the flow, and its vortices form the dipoles and the streams. Mechanisms are discussed for the growth of this slow component.