Evolution of an initially turbulent stratified shear layer
Evolution of an initially turbulent stratified shear layer
复制标题
最初湍流分层剪切层的演化
DOI：
10.1063/1.2756581
复制
发表时间：
2007
影响因子：
4.6
通讯作者：
S. Sarkar
中科院分区：
文献类型：
--
作者：
K. Brucker;S. Sarkar
直接数值模拟的分层剪切层进行了几个不同的值的雷诺数，批量理查森，和普朗特数。与以前的数值研究不同，初始扰动是湍流的。这些初始宽带扰动不允许形成明显的相干结构，如开尔文-亥姆霍兹辊和流向涡在以前的研究中发现。在没有分层的情况下，剪切层厚度线性增长，充分发展的湍流实现与以前的实验和数值数据一致的平均速度，湍流强度和湍流动能预算。当浮力包括在内时，剪切层增长到一个渐近厚度，相应的体Richardson数Rib在先前研究中发现的0.32±0.06范围内。肋的演变中的明显的分散示出有一个系统的依赖于雷诺数和普朗特数。浮力效应的详细描述...
Direct numerical simulations of a stratified shear layer are performed for several different values of Reynolds, bulk Richardson, and Prandtl numbers. Unlike previous numerical studies, the initial perturbations are turbulent. These initial broadband perturbations do not allow the formation of distinct coherent structures such as Kelvin-Helmholtz rollers and streamwise vortices found in previous studies. In the absence of stratification, the shear layer thickness grows linearly and fully developed turbulence is achieved with mean velocities, turbulence intensities, and turbulent kinetic energy budgets that agree well with previous experimental and numerical data. When buoyancy is included, the shear layer grows to an asymptotic thickness, and the corresponding bulk Richardson number, Rib, is within the range, 0.32±0.06, found in previous studies. The apparent scatter in the evolution of Rib is shown to have a systematic dependence on Reynolds and Prandtl numbers. A detailed description of buoyancy effects...