Elliptic instability of a curved Batchelor vortex
Elliptic instability of a curved Batchelor vortex
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弯曲巴彻勒涡旋的椭圆不稳定性
DOI：
10.1017/jfm.2016.533
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发表时间：
2016
影响因子：
3.7
通讯作者：
S. Le Dizès
中科院分区：
文献类型：
--
作者：
F. J. Blanco;S. Le Dizès
从理论上分析了环和螺旋涡中椭圆不稳定性的发生。 Moore 和 Saffman 开发的框架（Proc. R. Soc. Lond. A，第 346 卷，1975 年，第 413-425 页）将椭圆不稳定性解释为带有应变诱导校正的两个开尔文模式的共振，该框架用于获得弯曲和应变巴彻勒涡旋的一般稳定性特性。获得了三种主要不稳定模态特征的显式表达式，作为巴切勒涡流轴流参数的函数。我们表明涡旋曲率增加了椭圆不稳定性增长率的贡献。结果应用于单个涡流环、交替涡流环阵列和双螺旋涡流。
The occurrence of the elliptic instability in rings and helical vortices is analysed theoretically. The framework developed by Moore & Saffman (Proc. R. Soc. Lond. A, vol. 346, 1975, pp. 413–425), where the elliptic instability is interpreted as a resonance of two Kelvin modes with a strained induced correction, is used to obtain the general stability properties of a curved and strained Batchelor vortex. Explicit expressions for the characteristics of the three main unstable modes are obtained as a function of the axial flow parameter of the Batchelor vortex. We show that vortex curvature adds a contribution to the elliptic instability growth rate. The results are applied to a single vortex ring, an array of alternate vortex rings and a double helical vortex.