Velocity autocorrelations of decaying isotropic homogeneous turbulence
Velocity autocorrelations of decaying isotropic homogeneous turbulence
复制标题
衰减各向同性均匀湍流的速度自相关
DOI：
10.1063/1.868780
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发表时间：
1995
影响因子：
4.6
通讯作者：
A. Leonard
中科院分区：
文献类型：
--
作者：
Mei;A. Leonard
采用1283栅格和2563栅格对流场进行数值模拟，采用三阶插值方法跟踪数万个流体粒子，得到了衰减的各向同性均匀湍流中流体粒子的速度自相关性和均方位移。在观察幂律能量衰减，并假设[script T]s(T)与拉格朗日积分时间标度[script T] [script L]成正比的情况下，用无量纲时间变量s（ds=dt/[script T]s(T)）来定义自保拉格朗日速度自相关系数。这个时间标度又被假设成与含能涡流的长度标度[L]e~K3/2/epsilon除以湍流速度u[素数]成正比，其中K=3/2u[素数]2为湍流能量，epsilon为能量耗散率。
Velocity autocorrelations and the mean-square displacements of fluid particles are obtained for decaying, isotropic homogeneous turbulence by numerical simulation of the flow field, using 1283 and 2563 grids, and tracking several tens of thousands of fluid particles, using a third-order interpolation scheme. A self-preserving Lagrangian velocity autocorrelation coefficient is found in terms of a dimensionless time variable s, defined by ds=dt/[script T]s(t), under the observation of a power-law energy decay and the assumption that [script T]s(t) is proportional to the Lagrangian integral timescale [script T] [script L] . This timescale is in turn assumed to be proportional to the length scale of the energy-containing eddies [script L]e~K3/2/epsilon divided by the turbulent velocity u[prime], where K=3/2u[prime]2 is turbulent energy and epsilon is the energy dissipation rate.