Dynamics of saturated energy condensation in two-dimensional turbulence

被引:29
作者
Chan, Chi-kwan [1 ]
Mitra, Dhrubaditya [1 ]
Brandenburg, Axel [1 ,2 ]
机构
[1] NORDITA, SE-10691 Stockholm, Sweden
[2] Stockholm Univ, Dept Astron, SE-10691 Stockholm, Sweden
来源
PHYSICAL REVIEW E | 2012年 / 85卷 / 03期
基金
欧洲研究理事会; 瑞典研究理事会;
关键词
INVERSE CASCADE; GENERATION; DRIVEN;
D O I
10.1103/PhysRevE.85.036315
中图分类号
O35 [流体力学]; O53 [等离子体物理学];
学科分类号
070204 ; 080103 ; 080704 ;
摘要
In two-dimensional forced Navier-Stokes turbulence, energy cascades to the largest scales in the system to form a pair of coherent vortices known as the Bose condensate. We show, both numerically and analytically, that the energy condensation saturates and the system reaches a statistically stationary state. The time scale of saturation is inversely proportional to the viscosity and the saturation energy level is determined by both the viscosity and the force. We further show that, without sufficient resolution to resolve the small-scale enstrophy spectrum, numerical simulations can give a spurious result for the saturation energy level. We also find that the movement of the condensate is similar to the motion of an inertial particle with an effective drag force. Furthermore, we show that the profile of the saturated coherent vortices can be described by a Gaussian core with exponential wings.
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页数:8
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