A novel formulation of point vortex dynamics on the sphere: geometrical and numerical aspects
Abstract
In this paper, we present a novel Lagrangian formulation of the equations of motion for point vortices on the unit 2-sphere. We show first that no linear Lagrangian formulation exists directly on the 2-sphere but that a Lagrangian may be constructed by pulling back the dynamics to the 3-sphere by means of the Hopf fibration. We then use the isomorphism of the 3-sphere with the Lie group SU(2) to derive a variational Lie group integrator for point vortices which is symplectic, second-order, and preserves the unit-length constraint. At the end of the paper, we compare our integrator with classical fourth-order Runge--Kutta, the second-order midpoint method, and a standard Lie group Munthe-Kaas method.
Keywords
Cite
@article{arxiv.1211.4560,
title = {A novel formulation of point vortex dynamics on the sphere: geometrical and numerical aspects},
author = {Joris Vankerschaver and Melvin Leok},
journal= {arXiv preprint arXiv:1211.4560},
year = {2015}
}
Comments
40 pages, 10 figures. v2: simplified numerical algorithm, discussion of conservation laws