Fast relaxation of a viscous vortex in an external flow

Fuente: arXiv
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Autori principali: Donati, Martin, Gallay, Thierry
Natura: Preprint
Pubblicazione: 2025
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author Donati, Martin
Gallay, Thierry
author_facet Donati, Martin
Gallay, Thierry
contents We study the evolution of a concentrated vortex advected by a smooth, divergence-free velocity field in two space dimensions. In the idealized situation where the initial vorticity is a Dirac mass, we compute an approximation of the solution which accurately describes, in the regime of high Reynolds numbers, the motion of the vortex center and the deformation of the streamlines under the shear stress of the external flow. For ill-prepared initial data, corresponding to a sharply peaked Gaussian vortex, we prove relaxation to the previous solution on a time scale that is much shorter than the diffusive time, due to enhanced dissipation inside the vortex core.
format Preprint
id arxiv_https___arxiv_org_abs_2503_20643
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Fast relaxation of a viscous vortex in an external flow
Donati, Martin
Gallay, Thierry
Analysis of PDEs
Fluid Dynamics
35Q30, 35B35, 76D17
We study the evolution of a concentrated vortex advected by a smooth, divergence-free velocity field in two space dimensions. In the idealized situation where the initial vorticity is a Dirac mass, we compute an approximation of the solution which accurately describes, in the regime of high Reynolds numbers, the motion of the vortex center and the deformation of the streamlines under the shear stress of the external flow. For ill-prepared initial data, corresponding to a sharply peaked Gaussian vortex, we prove relaxation to the previous solution on a time scale that is much shorter than the diffusive time, due to enhanced dissipation inside the vortex core.
title Fast relaxation of a viscous vortex in an external flow
topic Analysis of PDEs
Fluid Dynamics
35Q30, 35B35, 76D17
url https://arxiv.org/abs/2503.20643