The curvature of material surfaces in isotropic turbulence
The curvature of material surfaces in isotropic turbulence
复制标题
各向同性湍流中材料表面的曲率
DOI：
10.1063/1.857474
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发表时间：
1989
影响因子：
4.6
通讯作者：
S. Girimaji
中科院分区：
文献类型：
--
作者：
S. Pope;P. Yeung;S. Girimaji
采用直接数值模拟方法研究了各向同性湍流中物质表面的曲率。Navier-Stokes方程通过643伪谱代码求解，用于恒定密度均匀各向同性湍流，该湍流通过低波数强迫统计稳定。泰勒尺度雷诺数为39。一个合奏的8192个无穷小的材料表面元素跟踪通过湍流。对于每个元件，在时间上对一组精确的常微分方程进行积分，以主要确定两个主曲率k1和k2。然后推导出均方曲率M=（1）/（2）（k21+k22）和平均曲率半径R=（k21+k22）−1/2的统计量。曲率统计在大约15个Kolmogorov时间尺度后达到基本稳定的状态。然后发现R的面积加权期望值为12η，其中η是柯尔莫哥洛夫长度尺度。对于中等和小半径（小于10η），R的概率密度函数（pdf）近似为unif。
Direct numerical simulation is used to study the curvature of material surfaces in isotropic turbulence. The Navier–Stokes equation is solved by a 643 pseudospectral code for constant‐density homogeneous isotropic turbulence, which is made statistically stationary by low‐wavenumber forcing. The Taylor‐scale Reynolds number is 39. An ensemble of 8192 infinitesimal material surface elements is tracked through the turbulence. For each element, a set of exact ordinary differential equations is integrated in time to determine, primarily, the two principal curvatures k1 and k2. Statistics are then deduced of the mean‐square curvature M= (1)/(2) (k21+k22), and of the mean radius of curvature R=(k21+k22)−1/2. Curvature statistics attain an essentially stationary state after about 15 Kolmogorov time scales. Then the area‐weighted expectation of R is found to be 12η, where η is the Kolmogorov length scale. For moderate and small radii (less than 10η) the probability density function (pdf) of R is approximately unif...