Interaction between a surface quasi-geostrophic buoyancy filament and an internal vortex
Interaction between a surface quasi-geostrophic buoyancy filament and an internal vortex
复制标题
表面准地转浮力丝与内部涡流之间的相互作用
DOI：
10.1080/03091929.2016.1233331
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发表时间：
2016
影响因子：
1.3
通讯作者：
X. Carton
中科院分区：
文献类型：
--
作者：
J. Reinaud;D. Dritschel;X. Carton
本文研究了表面准地转浮力丝与内部涡的非线性相互作用。我们首先重新审视一个孤立的浮力丝的稳定性。所考虑的浮力剖面是连续的，并导致一个连续的速度场，尽管它的边缘外有无限的剪切。孤立细丝的稳定性有助于解释其与亚表面（内部）涡旋的非定常相互作用。我们发现，在所有情况下，细丝破裂成波浪，类似于在开尔文-亥姆霍兹剪切不稳定中发生的形式。对于浮力强的细丝，漩涡本身可能会发生强烈的变形，包括分裂成几块。一般来说，非线性相互作用会使细丝和涡旋失去各自的“自我”能量而变成相互作用的能量。流动演变敏感地取决于细丝和涡旋的垂直涡度是否具有相同或相反的标志-分别称为“合作”和“不利”剪切。在协同剪切中，细丝向上卷成一个连贯的表面涡流，而在反向剪切中，浮力被排出在涡流上方。尽管在两种情况下，由浮力丝引起的足够大的剪切都可以使涡旋分裂，但不利剪切的破坏性要大得多。
This paper focuses on the nonlinear interaction between a surface quasi-geostrophic buoyancy filament and an internal vortex. We first revisit the stability of an isolated buoyancy filament. The buoyancy profile considered is continuous and leads to a continuous velocity field, albeit one with infinite shear just outside its edge. The stability properties of an isolated filament help to interpret the unsteady interaction with a sub-surface (internal) vortex studied next. We find that, in all cases, the filament breaks into billows, analogous in form to those occurring in Kelvin–Helmholtz shear instability. For intense buoyancy filaments, the vortex itself may undergo strong deformations, including being split into several pieces. Generally, the nonlinear interaction causes both the filament and the vortex to lose their respective “self”-energies to the energy of interaction. The flow evolution depends sensitively on whether the vertical vorticity of the filament and the vortex have the same or opposite signs – termed “cooperative” and “adverse” shear respectively. In cooperative shear, the filament rolls up into a coherent surface eddy above a vortex initially placed below it, whereas in adverse shear, buoyancy is expelled above the vortex. Although sufficiently great shear induced by the buoyancy filament may split the vortex in both cases, adverse shear is significantly more destructive.
小磁普朗特数极限下的二维磁流体动力湍流
影响因子：
3.7
作者：
Dritschel D
通讯作者：
Dritschel D