arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新,休息一下吧,周末愉快~~
arXiv 0807.0454math.DSmath-phmath.MP
收藏

抛物型三涡运动的临界解

Critical Solutions of Three Vortex Motion in the Parabolic Case

Lu Ting, Omar Knio, Denis Blackmore

摘要:

Grobli(1877)通过推导三角形涡旋构型的控制方程,为分析平面内三点涡旋的运动奠定了基础。Synge(1949)通过三线坐标将这个公式进一步推广到单位周长的类似三角形。最后减少的问题是由一个可积的二维系统的微分方程的解决方案表示为平面轨迹。另一个关键辛格的分析是他的分类问题分为三个不同的情况下:椭圆,双曲和抛物线相应的,分别是总和产品对涡强度是积极的,消极的或零。除了抛物线情况下沿临界平面曲线C外,涡结构从空间曲线到平面曲线的减少是一对一的。C上的每一点代表一个单位周长的三角形,对应于一系列相似的旋涡构型,膨胀或收缩。后者将导致三个涡旋的共融。Tavantzis和Ting(1988)填补了Synge在动力学问题上留下的大部分空白,并特别指出C上对应于相似的膨胀涡族的点是稳定的,而对应于相似的收缩涡族的点是不稳定的。他们的研究对平面内三个涡的运动和稳定性作了详尽的描述,但对含C的窄条中涡的整体行为作了描述。本文的主要贡献是完整地描述了这一条带的全球动力学,并证明了三个不同的涡旋几乎永远不会合并。

英文摘要:

Grobli (1877) laid the foundation for the analysis of the motion of three point vortices in a plane by deriving governing equations for triangular configurations of the vortices. Synge (1949) took this formulation one step further to that of a similar triangle of unit perimeter, via trilinear coordinates. The final reduced problem is governed by an integrable two-dimensional system of differential equations with solutions represented as planar trajectories. Another key to Synge's analysis was his classification of the problem into three distinct cases: elliptic, hyperbolic and parabolic corresponding, respectively, to the sum of products of pairs of vortex strengths being positive, negative or zero. The reduction of the vortex configuration, a curve in space to a planar curve is one-to-one, except along a critical planar curve C in the parabolic case. Each point on C represents a triangle of unit perimeter corresponding to a family of similar vortex configurations, expanding or contracting. The latter would lead to coelescence of the three vortices. Tavantzis and Ting (1988) filled most of the gaps left by Synge regarding the dynamics of the problem, and showed in particular that points on C corresponding to similar expanding families of vortex configurations are stable while those corresponding to similar contracting families are unstable. Their investigations yielded an exhaustive description of the motion and stability of three vortices in a plane except for the global behavior of the vortex configurations in a narrow strip containing C. The main contribution of this paper is a complete description of the global dynamics in such a strip, which emphaticallly demonstrates that three distinct vortices almost never coalesce.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑