Iyer Kartik P, Bewley Gregory P, Biferale Luca, Sreenivasan Katepalli R, Yeung P K
Department of Physics, Department of Mechanical Engineering-Engineering Mechanics, Michigan Technological University, Houghton, Michigan 49931, USA.
Department of Mechanical and Aerospace Engineering, New York University, New York, New York 11201, USA.
Phys Rev Lett. 2021 Jun 25;126(25):254501. doi: 10.1103/PhysRevLett.126.254501.
Inertial-range features of turbulence are investigated using data from experimental measurements of grid turbulence and direct numerical simulations of isotropic turbulence simulated in a periodic box, both at the Taylor-scale Reynolds number R_{λ}∼1000. In particular, oscillations modulating the power-law scaling in the inertial range are examined for structure functions up to sixth-order moments. The oscillations in exponent ratios decrease with increasing sample size in simulations, although in experiments they survive at a low value of 4 parts in 1000 even after massive averaging. The two datasets are consistent in their intermittent character but differ in small but observable respects. Neither the scaling exponents themselves nor all the viscous effects are consistently reproduced by existing models of intermittency.
利用在泰勒尺度雷诺数(R_{λ}∼1000)下的格栅湍流实验测量数据和在周期性盒子中模拟的各向同性湍流的直接数值模拟数据，研究了湍流的惯性范围特征。特别地，针对高达六阶矩的结构函数，研究了调制惯性范围内幂律标度的振荡。在模拟中，指数比的振荡随着样本量的增加而减小，尽管在实验中，即使经过大量平均，它们仍以千分之四的低值存在。这两个数据集在间歇性特征上是一致的，但在一些小的但可观察到的方面有所不同。现有的间歇性模型既不能一致地再现标度指数本身，也不能一致地再现所有粘性效应。
