Velocity field statistics in homogeneous steady turbulence obtained using a high-resolution direct numerical simulation
Velocity field statistics in homogeneous steady turbulence obtained using a high-resolution direct numerical simulation
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DOI：
10.1063/1.1448296
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发表时间：
2002-03-01
影响因子：
4.6
通讯作者：
Nakano, T
中科院分区：
文献类型：
--
作者：
Gotoh, T;Fukayama, D;Nakano, T
本文用N=1024（3）个网格点的高分辨率DNS数值模拟方法，研究了三维均匀定常湍流在惯性到耗散范围内的速度场统计特性。泰勒微尺度雷诺数的范围是在38和460之间。从积分尺度（L）的一半到Kolmogorov尺度（eta），在运动的小尺度下的各向同性都很好地满足。Kolmogorov常数为1.64+/-0.04，接近实验测定值。纵向速度差的三阶矩与分离距离r成比例，其系数接近4/5。在10阶速度差的矩中，观察到了一个清晰的惯性范围，在2 λ/2（约100 η）和L/2（约300 η）之间，其中λ是泰勒微尺度。标度指数直接从结构函数测量;当阶数大于4时，横向标度指数小于纵向指数。纵向速度结构函数的交叉长度随阶数的增加而增加，并接近2 λ，而横向速度结构函数的交叉长度在λ处保持近似恒定。讨论了泰勒微尺度的交叉长度和重要性。(C)2002年美国物理学会。
Velocity field statistics in the inertial to dissipation range of three-dimensional homogeneous steady turbulent flow are studied using a high-resolution DNS with up to N=1024(3) grid points. The range of the Taylor microscale Reynolds number is between 38 and 460. Isotropy at the small scales of motion is well satisfied from half the integral scale (L) down to the Kolmogorov scale (eta). The Kolmogorov constant is 1.64+/-0.04, which is close to experimentally determined values. The third order moment of the longitudinal velocity difference scales as the separation distance r, and its coefficient is close to 4/5. A clear inertial range is observed for moments of the velocity difference up to the tenth order, between 2lambdaapproximate to100eta and L/2approximate to300eta, where lambda is the Taylor microscale. The scaling exponents are measured directly from the structure functions; the transverse scaling exponents are smaller than the longitudinal exponents when the order is greater than four. The crossover length of the longitudinal velocity structure function increases with the order and approaches 2lambda, while that of the transverse function remains approximately constant at lambda. The crossover length and importance of the Taylor microscale are discussed. (C) 2002 American Institute of Physics.