Vortex axisymmetrization, inviscid damping, and vorticity depletion in the linearized 2D Euler equations
File(s)1711.03668v1.pdf (1.46 MB)
Accepted version
OA Location
Author(s)
Coti Zelati, M
Bedrossian, Jacob
Vicol, Vlad
Type
Journal Article
Abstract
Coherent vortices are often observed to persist for long times in turbulent 2D flows even at very high Reynolds numbers and are observed in experiments and computer simulations to potentially be asymptotically stable in a weak sense for the 2D Euler equations. We consider the incompressible 2D Euler equations linearized around a radially symmetric, strictly monotone decreasing vorticity distribution. For sufficiently regular data, we prove the inviscid damping of the θ-dependent radial and angular velocity fields with the optimal rates ∥ur(t)∥≲⟨t⟩−1 and ∥∥uθ(t)∥∥≲⟨t⟩−2 in the appropriate radially weighted L2 spaces. We moreover prove that the vorticity weakly converges back to radial symmetry as t→∞, a phenomenon known as vortex axisymmetrization in the physics literature, and characterize the dynamics in higher Sobolev spaces. Furthermore, we prove that the θ-dependent angular Fourier modes in the vorticity are ejected from the origin as t→∞, resulting in faster inviscid damping rates than those possible with passive scalar evolution. This non-local effect is called vorticity depletion. Our work appears to be the first to find vorticity depletion relevant for the dynamics of vortices.
Date Issued
2019-06-01
Date Acceptance
2019-01-29
Citation
Annals of Pde, 2019, 5 (1)
ISSN
2524-5317
Publisher
Springer International Publishing
Journal / Book Title
Annals of Pde
Volume
5
Issue
1
Identifier
https://arxiv.org/abs/1711.03668
Subjects
math.AP
math.AP
physics.ao-ph
physics.flu-dyn
physics.plasm-ph
Article Number
4
Date Publish Online
2019-02-12