Enhanced Dissipation and Axisymmetrization of Two-Dimensional Viscous Vortices
Enhanced Dissipation and Axisymmetrization of Two-Dimensional Viscous Vortices
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DOI：
10.1007/s00205-018-1262-0
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发表时间：
2017-07
影响因子：
2.5
通讯作者：
T. Gallay
中科院分区：
文献类型：
--
作者：
T. Gallay
本文研究了高环量雷诺数下Lamb-Oseen涡的稳定性。当施加强烈的局部扰动时，它示出的涡松弛成轴对称的时间成正比，这是大大短于由粘度给出的扩散时间尺度。这种增强的耗散效应是由于涡核内部的差异旋转。我们的结果依赖于李等人最近的工作。（Oseen涡旋算子的伪谱和谱界，2017年， 1701.06269 ），其中最佳的预解估计的线性算子在Oseen的涡建立。与可以在物理文献中找到的预测，并与使用不同的技术获得的剪切流的严格的结果进行比较。
This paper is devoted to the stability analysis of the Lamb–Oseen vortex in the regime of high circulation Reynolds numbers. When strongly localized perturbations are applied, it is shown that the vortex relaxes to axisymmetry in a time proportional to, which is substantially shorter than the diffusion time scale given by the viscosity. This enhanced dissipation effect is due to the differential rotation inside the vortex core. Our result relies on a recent work by Li et al. (Pseudospectral and spectral bounds for the Oseen vortices operator, 2017, arXiv:1701.06269 ), where optimal resolvent estimates for the linearized operator at Oseen’s vortex are established. A comparison is made with the predictions that can be found in the physical literature, and with the rigorous results that were obtained for shear flows using different techniques.