Three-dimensional flow in electromagnetically driven shallow two-layer fluids.
Three-dimensional flow in electromagnetically driven shallow two-layer fluids.
复制标题
电磁驱动浅层两层流体中的三维流动。
DOI：
10.1103/physreve.82.026314
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
V. Heijst
中科院分区：
文献类型：
--
作者：
Rad Rinie Akkermans;L. Kamp;H. Clercx;V. Heijst
最近的实验中，一个自由发展的偶极涡在一个均匀的浅流体层已经清楚地显示了复杂的三维（3D）流动结构的存在和演变。本文主要研究稳定的浅层两层流体中偶极涡旋的三维结构。在实验上，立体粒子图像测速法用于瞬时测量水平面内速度场的所有三个分量，并且3D数值模拟提供了整个流域上的完整3D速度和涡量场。值得注意的是，实验结果，支持的数值模拟，显示在很大程度上相同的三维结构和演变的单层的情况下。数值模拟表明，所谓的锋面环流的两层流体是由于内部界面的变形。三维流动结构也会影响自由表面释放的无质量被动颗粒的分布。与数值研究表明，这些被动粒子往往积累或耗尽本地的水平速度场是不是发散自由。这与纯二维不可压缩流形成对比，在纯二维不可压缩流中，速度场的发散度按定义为零。
Recent experiments on a freely evolving dipolar vortex in a homogeneous shallow fluid layer have clearly shown the existence and evolution of complex three-dimensional (3D) flow structures. The present contribution focuses on the 3D structures of a dipolar vortex evolving in a stable shallow two-layer fluid. 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. Remarkably, the experimental results, supported by the numerical simulations, show to a large extent the same 3D structures and evolution as in the single-layer case. The numerical simulations indicate that the so-called frontal circulation in the two-layer fluid is due to deformations of the internal interface. The 3D flow structures will also affect the distribution of massless passive particles released at the free surface. With numerical studies it is shown that these passive particles tend to accumulate or deplete locally where the horizontal velocity field is not divergence-free. This is in contrast with pure two-dimensional incompressible flows where the divergence of the velocity field is zero by definition.