Correlations of vorticity and material line elements with strain in decaying turbulence
Correlations of vorticity and material line elements with strain in decaying turbulence
复制标题
涡度和物质线元素与衰减湍流应变的相关性
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
Mei
中科院分区：
文献类型：
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作者：
Mei
研究了衰减湍流中涡量和被动材料线元与应变的相关性。应变的平均主速率、涡量的增长速率和非线性拉伸引起的物质线元的增长速率都与均方根拟能成正比。主要利率比率为4：1：-5。它显示了这些比率如何帮助确定湍流的唯象模型中的自由参数值，如Ashurst提出的Burgers涡模型（私人通讯）和Pullin和Saffman提出的Lundamental-Townsend涡模型[Phys. Fluids A 5，126（1993）; 6，3010（1994）]。物质线元的平均增长率略大于中间主增长率，但远小于最大正增长率。数值结果表明，材料线元在大部分正应变和大部分负应变对应的应变主方向上具有几乎相同的取向。
Correlations of the vorticity and the passive material line element with strains in decaying turbulence are investigated. The mean principal rates of the strain and the growth rates of the vorticity and the material line element due to the nonlinear stretching are all found to be proportional to the square‐root‐mean enstrophy. The ratios of the principal rates are 4:1:−5. It is shown how these ratios help determining the values of free parameters in the phenomenological models of turbulence such as the Burgers vortex model proposed by Ashurst (private communication) and the Lundgren–Townsend vortex model by Pullin and Saffman [Phys. Fluids A 5, 126 (1993); 6, 3010 (1994)]. The mean growth rate of material line elements is slightly larger than the intermediate principal rate, but much less than the most positive one. Numerical results show that the material line element has nearly the same preferences in aligning with the principal directions of the strain corresponding to the mostly positive and the inter...