Highly symmetric travelling waves in pipe flow
Highly symmetric travelling waves in pipe flow
复制标题
管流中高度对称的行波
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
R. Kerswell
中科院分区：
文献类型：
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作者：
C. Pringle;Y. Duguet;R. Kerswell
管流中有限振幅行波的最新理论发现重新引起了人们对奥斯本·雷诺125年前研究的过渡现象的兴趣。尽管一切都不稳定，但这些波浪为流动动力学提供了新的见解。我们描述了两类新的TW，它们具有比先前发现的Faisst&Eck hardt(2003 Phys.莱特牧师。91,224502)和韦丁和克斯韦尔(2004年J.流体机械。508,333-371)，似乎对精确解的层次结构更基本。它们表现出更高的壁面剪应力，并且在明显较低的雷诺数下出现。第一个M级包括在Pringle&Kerswell(2007 Phys.)中发现的镜像对称波的各种离散旋转对称类似物。莱特牧师。99,074502)，并在管道半径上具有独特的快慢条纹的双层结构。第二个N级波具有更常见的外部快速条纹和内部慢速条纹的分离，看起来像是已知的非镜对称波的前驱。
The recent theoretical discovery of finite-amplitude travelling waves (TWs) in pipe flow has reignited interest in the transitional phenomena that Osborne Reynolds studied 125 years ago. Despite all being unstable, these waves are providing fresh insight into the flow dynamics. We describe two new classes of TWs, which, while possessing more restrictive symmetries than previously found TWs of Faisst & Eckhardt (2003 Phys. Rev. Lett. 91, 224502) and Wedin & Kerswell (2004 J. Fluid Mech. 508, 333–371), seem to be more fundamental to the hierarchy of exact solutions. They exhibit much higher wall shear stresses and appear at notably lower Reynolds numbers. The first M-class comprises the various discrete rotationally symmetric analogues of the mirror-symmetric wave found in Pringle & Kerswell (2007 Phys. Rev. Lett. 99, 074502), and have a distinctive double-layered structure of fast and slow streaks across the pipe radius. The second N-class has the more familiar separation of fast streaks to the exterior and slow streaks to the interior and looks like the precursor to the class of non-mirror-symmetric waves already known.