On concentrated vortices of 3D incompressible Euler equations under helical symmetry: with swirl

Abstract

In this paper, we consider the existence of concentrated helical vortices of 3D incompressible Euler equations with swirl. First, without the assumption of the orthogonality condition, we derive a 2D vorticity-stream formulation of 3D incompressible Euler equations under helical symmetry. Then based on this system, we deduce a non-autonomous second order semilinear elliptic equations in divergence form, whose solutions correspond to traveling-rotating invariant helical vortices with non-zero helical swirl. Finally, by using Arnold's variational method, that is, finding maximizers of a properly defined energy functional over a certain function space and proving the asymptotic behavior of maximizers, we construct families of concentrated traveling-rotating helical vortices of 3D incompressible Euler equations with non-zero helical swirl in infinite cylinders. As parameter $ \varepsilon\to0 $, the associated vorticity fields tend asymptotically to a singular helical vortex filament evolved by the binormal curvature flow.