Passage of a Barotropic Vortex through a Gap
Passage of a Barotropic Vortex through a Gap
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正压涡旋穿过间隙
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
O. V. Fuentes
中科院分区：
文献类型：
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作者：
M. Duran‐Matute;O. V. Fuentes
研究了匀流平流对直障隙的涡旋流动。这是在世界海洋中观察到的流动的理想化，例如，在尤卡坦海峡和小安的列斯群岛的各种通道。研究了涡旋的演化和输运特性与涡旋强度、涡旋初始位置和间隙宽度等三维参数的关系。采用二维无粘模型对流动演化过程进行了数值计算。观察到涡旋以以下方式之一表现：它完全穿过间隙，它分裂，只有一小部分通过，或者它完全停留在壁面的上游。在每种情况下，使用拉格朗日流动几何、有限尺寸李雅普诺夫指数和流体颗粒的停留时间来分析输运和混合。实验室实验是在均匀的旋转流体中进行的。在导致涡旋总通过的参数空间区域，实验室观测到的演化与数值计算结果吻合较好。在参数空间的部分通道和完全堵塞区域，只有在壁面涡量的产生变得重要之前，一致性才良好。
The flow of a vortex advected by a uniform current toward a gap in a straight barrier is studied. This is an idealization of flows observed in the world’s oceans, for example, in the Yucatan Channel and in the various passages of the Lesser Antilles. The vortex evolution and the transport properties are studied as a function of three nondimensional parameters related to the vortex intensity, the vortex initial position, and the gap’s span. The flow evolution is computed numerically with a two-dimensional inviscid model. The vortex is observed to behave in one of the following ways: it passes completely through the gap, it splits and only a fraction passes, or it stays entirely in the upstream side of the wall. In each of these regimes, transport and mixing are analyzed using the Lagrangian flow geometry, finite-size Lyapunov exponents, and residence times of fluid particles. Laboratory experiments are performed in a homogeneous, rotating fluid. In the region of parameter space that leads to total passage of the vortex, there is good agreement between the evolution observed in the laboratory and that obtained numerically. In the regions of parameter space, which lead to partial passage and full blockage, the agreement is good only until the generation of vorticity on the walls becomes important.