Laboratoire Cassiopée, Observatoire de la Côte d'Azur, UNS, CNRS, BP 4229, 06304 Nice Cedex 4, France.
Phys Rev Lett. 2011 Oct 28;107(18):184503. doi: 10.1103/PhysRevLett.107.184503. Epub 2011 Oct 26.
We obtain, by extensive direct numerical simulations, time-dependent and equal-time structure functions for the vorticity, in both quasi-Lagrangian and Eulerian frames, for the direct-cascade regime in two-dimensional fluid turbulence with air-drag-induced friction. We show that different ways of extracting time scales from these time-dependent structure functions lead to different dynamic-multiscaling exponents, which are related to equal-time multiscaling exponents by different classes of bridge relations; for a representative value of the friction we verify that, given our error bars, these bridge relations hold.
我们通过广泛的直接数值模拟，获得了二维流体湍流中带有空气阻力摩擦的直接串级区在拟拉格朗日和欧拉框架中，涡度的时变和等时结构函数。我们表明，从这些时变结构函数中提取时间尺度的不同方法会导致不同的动力多标度指数，这些指数通过不同类别的桥接关系与等时多标度指数相关；对于摩擦的一个代表性值，我们验证了，在我们的误差范围内，这些桥接关系成立。
