Viscous selection of an elliptical dipole
Viscous selection of an elliptical dipole
复制标题
椭圆偶极子的粘性选择
DOI：
10.1017/s0022112010001813
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发表时间：
2010
影响因子：
3.7
通讯作者：
D. Kessler
中科院分区：
文献类型：
--
作者：
Z. Kizner;R. Khvoles;D. Kessler
基于数值模拟和渐近分析相结合的方法，提出了对称二维偶极子的粘性演化和选择理论，其中考虑了由粘性引起的涡度扩散的慢时间尺度。结果表明，黏度首先使偶极子达到与初始条件无关的中间渐近状态，然后逐渐使偶极子远离该状态。我们证明，在各种可能的理想流体偶极子解中，粘度趋于零选择了一个唯一解，该解被分离矩阵长径比为1.037的椭圆偶极子解高精度地描述。
A theory of viscous evolution and selection of symmetric two-dimensional dipoles is suggested, based on a combination of numerical simulations and an asymptotic analysis, where the slow time scale associated with the vorticity diffusion due to viscosity is incorporated. It is shown that viscosity first brings a dipole to an intermediate asymptotic state, which is independent of the initial conditions, and then slowly takes the dipole away from this state. We demonstrate that, among the variety of possible ideal-fluid dipole solutions, viscosity going to zero selects a unique solution, which is described to high accuracy by the elliptical dipole solution with a separatrix aspect ratio of 1.037.