Bistability of the large-scale dynamics in quasi-two-dimensional turbulence
Bistability of the large-scale dynamics in quasi-two-dimensional turbulence
复制标题
准二维湍流大尺度动力学的双稳定性
DOI：
10.1017/jfm.2022.209
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发表时间：
2022
影响因子：
3.7
通讯作者：
Alexakis, Alexandros
中科院分区：
文献类型：
--
作者：
de Wit, Xander M.;van Kan, Adrian;Alexakis, Alexandros
在许多地球物理学和天体物理学的流动中，沿沿着一个流动方向的波动的抑制驱动准二维的高通量动能，导致在最大尺度上形成强涡旋凝聚。最近的研究表明，向这种凝聚态的过渡是滞后的，产生了一个有限的范围内的凝聚态以及规则的三维状态可以存在于相同的参数值。在这项工作中，我们使用直接的数值模拟薄层流动，以调查是否这个范围内生存的域的大小和湍流强度的增加。通过研究从一种状态到另一种状态的罕见转变发生的时间尺度，我们发现，在任何有限的时间尺度上，从一种状态到另一种状态的任何转变都是被禁止的，并且随着盒子的大小和/或雷诺数的增加，这种转变的范围也会增加。
In many geophysical and astrophysical flows, suppression of fluctuations along one direction of the flow drives a quasi-two-dimensional upscale flux of kinetic energy, leading to the formation of strong vortex condensates at the largest scales. Recent studies have shown that the transition towards this condensate state is hysteretic, giving rise to a limited bistable range in which both the condensate state as well as the regular three-dimensional state can exist at the same parameter values. In this work, we use direct numerical simulations of thin-layer flow to investigate whether this bistable range survives as the domain size and turbulence intensity are increased. By studying the time scales at which rare transitions occur from one state into the other, we find that the bistable range grows as the box size and/or Reynolds number , in which any transition from one state to the other is prohibited at any finite time scale.