Dynamics of Energy Condensation in TwoDimensional Turbulence
Abstract
We report a numerical study, supplemented by phenomenological explanations, of “energy condensation” in forced 2D turbulence in a biperiodic box. Condensation is a finite size effect which occurs after the standard inverse cascade reaches the size of the system. It leads to the emergence of a coherent vortex dipole. We show that the time growth of the dipole is selfsimilar, and it contains most of the injected energy, thus resulting in an energy spectrum which is markedly steeper than the standard k^{5/3} one. Once the coherent component is subtracted, however, the remaining fluctuations have a spectrum close to k^{1}. The fluctuations decay slowly as the coherent part grows.
 Publication:

Physical Review Letters
 Pub Date:
 August 2007
 DOI:
 10.1103/PhysRevLett.99.084501
 arXiv:
 arXiv:nlin/0612052
 Bibcode:
 2007PhRvL..99h4501C
 Keywords:

 47.27.E;
 92.60.hk;
 Turbulence simulation and modeling;
 Convection turbulence and diffusion;
 Nonlinear Sciences  Chaotic Dynamics;
 Condensed Matter  Statistical Mechanics;
 Physics  Fluid Dynamics
 EPrint:
 4 pages, 4 figures. This version includes some additional phenomenological explanations of the results, additional references and improved figures