An inverse cascade - energy transfer to progressively larger scales - is a salient feature of two-dimensional turbulence. If the cascade reaches the system scale, it creates a coherent flow expected to have the largest available scale and conform with the symmetries of the domain. In a doubly periodic rectangle, the mean flow with zero total momentum was therefore believed to be unidirectional, with two jets along the short side; while for an aspect ratio close to unity, a vortex dipole was...

Topics: Nonlinear Sciences, Fluid Dynamics, Atmospheric and Oceanic Physics, Statistical Mechanics,...

Source: http://arxiv.org/abs/1608.04628