Radial symmetry of stationary and uniformly-rotating solutions to the 2D Euler equation in a disc

Fuente: arXiv
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Autori principali: Fan, Boquan, Wang, Yuchen, Zhan, Weicheng
Natura: Preprint
Pubblicazione: 2024
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author Fan, Boquan
Wang, Yuchen
Zhan, Weicheng
author_facet Fan, Boquan
Wang, Yuchen
Zhan, Weicheng
contents We study the radial symmetry properties of stationary and uniformly rotating solutions of the 2D Euler equation in the unit disc, both in the smooth setting and the patch setting. In the patch setting, we prove that every uniformly rotating patch with angular velocity $Ω\le 0$ or $Ω\ge 1/2$ must be radial, where both bounds are sharp. The conclusion holds under the assumption that the rotating patch considered is disconnected, with its boundaries consisting of several Jordan curves. We also show that every uniformly rotating smooth solution $ω_0$ must be radially symmetric if its angular velocity $Ω\le \inf ω_0/2$ or $Ω\ge \sup ω_0/2$. The proof is based on the symmetry properties of non-negative solutions to elliptic problems. A newly tailored approach is developed to address the symmetries of non-negative solutions to piecewise coupled semi-linear elliptic equations.
format Preprint
id arxiv_https___arxiv_org_abs_2412_05973
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Radial symmetry of stationary and uniformly-rotating solutions to the 2D Euler equation in a disc
Fan, Boquan
Wang, Yuchen
Zhan, Weicheng
Analysis of PDEs
We study the radial symmetry properties of stationary and uniformly rotating solutions of the 2D Euler equation in the unit disc, both in the smooth setting and the patch setting. In the patch setting, we prove that every uniformly rotating patch with angular velocity $Ω\le 0$ or $Ω\ge 1/2$ must be radial, where both bounds are sharp. The conclusion holds under the assumption that the rotating patch considered is disconnected, with its boundaries consisting of several Jordan curves. We also show that every uniformly rotating smooth solution $ω_0$ must be radially symmetric if its angular velocity $Ω\le \inf ω_0/2$ or $Ω\ge \sup ω_0/2$. The proof is based on the symmetry properties of non-negative solutions to elliptic problems. A newly tailored approach is developed to address the symmetries of non-negative solutions to piecewise coupled semi-linear elliptic equations.
title Radial symmetry of stationary and uniformly-rotating solutions to the 2D Euler equation in a disc
topic Analysis of PDEs
url https://arxiv.org/abs/2412.05973