论文标题
liouville连锁:2D Euler方程的新混合涡流平衡
Liouville chains: new hybrid vortex equilibria of the 2D Euler equation
论文作者
论文摘要
提出了一类新的精确解决方案,用于平面上稳定,不可压缩的欧拉方程。这些混合溶液由一组固定点涡旋组成,该涡流嵌入了liouville型涡旋的背景海中,该涡度与流函数成倍相关。该结构的输入是背景无关流中的“纯”点涡流平衡。 Pure Point Vortex Equilibria在混合解决方案中的参数$ a $也显示为限制$ a \ a \ 0,\ infty $。 $ a \至0 $重现输入平衡,而$ a \ to \ infty $产生新的纯点涡流平衡。我们指的是混合平衡的家族,由$ a $连续参数为“ liouville链接”。在某些情况下,新兴点涡流平衡为$ a \ to \ infty $本身可以是第二个混合平衡系列的输入,以限制到另一个纯点涡流平衡。这样,liouville将链接在一起形成“ liouville链”。我们讨论了Liouville连锁店的几个例子,并证明它们可以具有有限的或无限的链接。我们在这里表明,Crowdy(2003)和Krishnamurthy等人发现的混合解决方案类别。 (2019年)形成了这样一个无限链中的前两个链接。我们还表明,Krishnamurthy等人最近研究的固定点涡流平衡。 (2020)可以解释为liouville链接的极限。我们的结果表明,二维Euler方程的这类均衡基础是丰富的理论结构。
A large class of new exact solutions to the steady, incompressible Euler equation on the plane is presented. These hybrid solutions consist of a set of stationary point vortices embedded in a background sea of Liouville-type vorticity that is exponentially related to the stream function. The input to the construction is a "pure" point vortex equilibrium in a background irrotational flow. Pure point vortex equilibria also appear as a parameter $A$ in the hybrid solutions approaches the limits $A\to 0,\infty$. While $A\to 0$ reproduces the input equilibrium, $A\to\infty$ produces a new pure point vortex equilibrium. We refer to the family of hybrid equilibria continuously parametrised by $A$ as a "Liouville link". In some cases, the emergent point vortex equilibrium as $A\to\infty$ can itself be the input for a second family of hybrid equilibria linking, in a limit, to yet another pure point vortex equilibrium. In this way, Liouville links together form a "Liouville chain". We discuss several examples of Liouville chains and demonstrate that they can have a finite or an infinite number of links. We show here that the class of hybrid solutions found by Crowdy (2003) and by Krishnamurthy et al. (2019) form the first two links in one such infinite chain. We also show that the stationary point vortex equilibria recently studied by Krishnamurthy et al. (2020) can be interpreted as the limits of a Liouville link. Our results point to a rich theoretical structure underlying this class of equilibria of the 2D Euler equation.