The three-dimensional structure of an electromagnetically generated dipolar vortex in a shallow fluid layer
The three-dimensional structure of an electromagnetically generated dipolar vortex in a shallow fluid layer
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DOI：
10.1063/1.3005452
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发表时间：
2008-11
影响因子：
4.6
通讯作者：
Rad Rinie Akkermans;A. Cieslik;L. Kamp;R. Trieling;H. Clercx;V. Heijst
中科院分区：
文献类型：
--
作者：
Rad Rinie Akkermans;A. Cieslik;L. Kamp;R. Trieling;H. Clercx;V. Heijst
在电磁驱动的浅层流体中已经进行了许多实验来研究准二维(Q2D)湍流，通常假设层的浅度来保证Q2D动力学。然而，在本文中，我们论证了浅层流体流动表现出复杂的三维(3D)结构。为此，我们研究了Q2D湍流中的一种基本旋涡结构--浅层流体中的偶极旋涡。通过实验和数值模拟相结合的方法对流动演化进行了研究。在实验上，利用立体粒子图像测速仪在水平面上瞬时测量速度场的所有三个分量，三维数值模拟提供了整个流场的三维速度场和涡量场。研究发现，在整个流动演化过程中，即在强迫相期间和之后，都会出现显著而复杂的三维结构和垂直运动。得出底摩擦力不是L的主要作用机制的结论。
Many experiments have been performed in electromagnetically driven shallow fluid layers to study quasi-two-dimensional (Q2D) turbulence, the shallowness of the layer commonly is assumed to ensure Q2D dynamics. In this paper, however, we demonstrate that shallow fluid flows exhibit complex three-dimensional (3D) structures. For this purpose we study one of the elementary vortex structures in Q2D turbulence, the dipolar vortex, in a shallow fluid layer. The flow evolution is studied both experimentally and by numerical simulations. Experimentally, stereoscopic particle image velocimetry is used to measure instantaneously all three components of the velocity field in a horizontal plane, and 3D numerical simulations provide the full 3D velocity and vorticity fields over the entire flow domain. It is found that significant and complex 3D structures and vertical motions occur throughout the flow evolution, i.e., during and after the forcing phase. We conclude that the bottom friction is not the main mechanism l...