Direct numerical simulation study of the interaction between the polymer effect and velocity gradient tensor in decaying homogeneous isotropic turbulence

Direct numerical simulation of decaying homogeneous isotropic turbulence （DHIT） of a polymer solution is performed. In order to understand the polymer effect on turbulence or additive-turbulence interaction, we directly investigate the influence of polymers on velocity gradient tensor including vort...

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Bibliographic Details
Published in:Chinese physics B 2011-12, Vol.20 (12), p.279-292, Article 124702
Main Author: 蔡伟华 李凤臣 张红娜
Format: Article
Language:English
Subjects:
Decay
Fluid flow
Inhibition
Mathematical analysis
Tensors
Tubes
Turbulence
Turbulent flow
Vorticity
均匀各向同性湍流
张量
直接数值模拟
联合概率密度
聚合效应
聚合物溶液
衰减
速度梯度
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Summary:Direct numerical simulation of decaying homogeneous isotropic turbulence （DHIT） of a polymer solution is performed. In order to understand the polymer effect on turbulence or additive-turbulence interaction, we directly investigate the influence of polymers on velocity gradient tensor including vorticity and strain. By visualizing vortex tubes and sheets, we observe a remarkable inhibition of vortex structures in an intermediate-scale field and a small-scale field but not for a large scale field in DHIT with polymers. The geometric study indicates a strong relevance among the vorticity vector, rate-of-strain tensor, and polymer conformation tensor. Joint probability density functions show that the polymer effect can increase ＂strain generation resistance＂ and ＂vorticity generation resistance＂, i.e., inhibit the generation of vortex sheets and tubes, ultimately leading to turbulence inhibition effects.
ISSN:1674-1056
2058-3834
1741-4199
DOI:10.1088/1674-1056/20/12/124702