Stress field analysis around vortex in elastic layer of viscoelastic turbulent channel flow
Stress field analysis around vortex in elastic layer of viscoelastic turbulent channel flow
复制标题
粘弹性湍流通道流弹性层涡周围应力场分析
DOI：
10.1088/1742-6596/530/1/012059
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
Y. Kawaguchi
中科院分区：
文献类型：
--
作者：
T. Minegishi;T. Tsukahara;Y. Kawaguchi
从工程角度来看，理解减阻粘弹性流动非常重要，因为理解减阻机制可能有助于设计更好的添加剂类型和/或通道配置。本文采用直接数值模拟的方法研究了粘弹性流体在平行平面间充分发展的湍流中涡的衰减。我们讨论了粘弹性应力如何在减少涡流周围的湍流运动中发挥作用，以及它如何影响整个流场。为了确定粘弹性的主要影响，我们将涡旋演化分为三个阶段，并对每个阶段的统计数据进行了检验。我们用涡度和旋转粘弹性应力之间的乘积或相关性来阐明速度场和粘弹性应力场之间的关系。研究发现，对湍流的抑制作用主要体现在两个方面：一是通道内较大范围的粘弹性应力对纵向涡的阻尼作用；二是涡生长状态下的应力对涡的松弛作用。
It is important from an engineering aspect to understand drag-reducing viscoelastic flow, since comprehension of the drag-reduction mechanism may facilitate designs with better additive types and/or channel configurations. In this study, we investigated the attenuation of vortices in fully-developed turbulence of viscoelastic fluid between parallel planes by DNS (Direct Numerical Simulation). We discussed how the viscoelastic stress play a role in the reduction of the turbulent motions around vortices and how it influences the entire flow field. For determining the major effect of viscoelasticity, we classified three stages of vortex evolution and examined statistical data for each stage. We clarified the relation between the velocity field and viscoelastic stress field using a product, or a correlation, between vorticity and rotational viscoelastic stress. We found that the inhibition of turbulence would be caused by the following aspects: damping longitudinal vortex by viscoelastic stress over a wide range in the channel, and relaxing development of vortex by the stress in vortex growing state.