CHAOTIC TRANSPORT BY ROSSBY WAVES IN SHEAR-FLOW
CHAOTIC TRANSPORT BY ROSSBY WAVES IN SHEAR-FLOW
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DOI：
10.1063/1.858639
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发表时间：
1993-04-01
期刊：
影响因子：
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通讯作者：
MORRISON, PJ
中科院分区：
文献类型：
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作者：
DELCASTILLONEGRETE, D;MORRISON, PJ
利用Hamilton混沌理论研究了剪切流中Rossby波的输运和混合特性。通过共振重叠准则和分界线重联的概念，分析研究了障碍物对输运的破坏，并通过使用庞加莱截面进行了数值计算。注意力仅限于对称的速度分布的情况下，一个单一的最大值，比克利射流速度分布sech 2被认为是详细的。基于线性稳定性分析和实验结果，提出了一个简单的哈密顿模型来研究这些剪切流中的波输运。混沌运输，无论是一般情况下，sech2配置文件，进行了研究。共振重叠准则和分界线重连的概念被用来获得一个估计的破坏障碍运输和带状混沌的概念被引入到表征的运输，通常发生在对称剪切流。屏障破坏的分析估计和数值结果之间的比较。讨论了位涡守恒在混沌输运中的作用。从Hamilton模型出发，得到了一个保面积映射，称为标准无扭映射.结果表明，该映射再现了哈密顿模型中观察到的输运性质和分界线重联。所得结论用于解释旋转流体中Rossby波输运和混合的实验结果。
Transport and mixing properties of Rossby waves in shear flow are studied using tools from Hamiltonian chaos theory. The destruction of barriers to transport is studied analytically, by using the resonance overlap criterion and the concept of separatrix reconnection, and numerically by using Poincare sections. Attention is restricted to the case of symmetric velocity profiles with a single maximum; the Bickley jet with velocity profile sech2 is considered in detail. Motivated by linear stability analysis and experimental results, a simple Hamiltonian model is proposed to study transport by waves in these shear flows. Chaotic transport, both for the general case and for the sech2 profile, is investigated. The resonance overlap criterion and the concept of separatrix reconnection are used to obtain an estimate for the destruction of barriers to transport and the notion of banded chaos is introduced to characterize the transport that typically occurs in symmetric shear flows. Comparison between the analytical estimates for barrier destruction and the numerical results is given. The role of potential vorticity conservation in chaotic transport is discussed. An area preserving map, termed standard nontwist map, is obtained from the Hamiltonian model. It is shown that the map reproduces the transport properties and the separatrix reconnection observed in the Hamiltonian model. The conclusions reached are used to explain experimental results on transport and mixing by Rossby waves in rotating fluids.