Dubos T, Babiano A, Paret J, Tabeling P
Laboratoire de Météorologie Dynamique, Ecole Normale Supérieure, 24 rue Lhomond, 75005 Paris, France.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 Sep;64(3 Pt 2):036302. doi: 10.1103/PhysRevE.64.036302. Epub 2001 Aug 29.
We study the internal intermittency in the inverse energy cascade and in the condensation regime of two-dimensional turbulence, using physical and numerical experimental approaches. The analysis confirms that the velocity increments have nearly Gaussian distributions at all scales in the inverse cascade regime; it moreover shows that, in the condensation regime, the probability distribution functions of the velocity increments are non-Gaussian but do not significantly vary with the scale; it follows that one may consider that there is essentially no intermittency (in the usual sense), in the condensation regime. In both regimes, we emphasize that coherent structures (i.e., long-lived vortices) are clearly visible on the vorticity field, and we suggest the non-Gaussianity of the distributions in the condensation regime is due to the presence of a large-scale long-lived structures. The study is supplemented by the analysis of the distribution of energy transfers at various scales.
我们使用物理和数值实验方法研究二维湍流的逆能量级串和凝聚 regime 中的内间歇性。分析证实，在逆级串 regime 中，速度增量在所有尺度上都具有近似高斯分布；此外还表明，在凝聚 regime 中，速度增量的概率分布函数是非高斯的，但不随尺度显著变化；由此可知，在凝聚 regime 中，基本上可以认为不存在（通常意义上的）间歇性。在这两种 regime 中，我们强调在涡度场上清晰可见相干结构（即长寿命涡旋），并且我们认为凝聚 regime 中分布的非高斯性是由于存在大规模长寿命结构。该研究通过对不同尺度能量转移分布的分析得到补充。
