Stability threshold of Couette flow for Boussinesq equations in $\mathbb{R}^2$

Fuente: arXiv
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Auteurs principaux: Chen, Yubo, Wang, Wendong, Yang, Guoxu
Format: Preprint
Publié: 2025
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author Chen, Yubo
Wang, Wendong
Yang, Guoxu
author_facet Chen, Yubo
Wang, Wendong
Yang, Guoxu
contents This paper establishes the asymptotic stability threshold for the Couette flow $(y,0)$ under the 2D Boussinesq system in $\mathbb{R}^2$. It was proved that for initial perturbations in Sobolev spaces with controlled low horizontal frequencies, the stability threshold is at most $\left\{\frac{1}{3}+, \frac{2}{3}+\right\}$, extending the known threshold results from the periodic case $\mathbb{T}_x \times \mathbb{R}_y$ to the whole space. The core innovations are twofold: First, the $\langle D_x^{-1} \rangle$ control on the initial data simultaneously resolves horizontal frequency singularities and optimizes integral indices when applying Young's convolution inequality. Second, we develop a modified multiplier $\mathcal{M}_3$ that effectively absorbs the $|D_x|^{1/3}$ derivative structure induced by the temperature equation while handling nonlinear echo cascades.
format Preprint
id arxiv_https___arxiv_org_abs_2508_11908
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Stability threshold of Couette flow for Boussinesq equations in $\mathbb{R}^2$
Chen, Yubo
Wang, Wendong
Yang, Guoxu
Analysis of PDEs
This paper establishes the asymptotic stability threshold for the Couette flow $(y,0)$ under the 2D Boussinesq system in $\mathbb{R}^2$. It was proved that for initial perturbations in Sobolev spaces with controlled low horizontal frequencies, the stability threshold is at most $\left\{\frac{1}{3}+, \frac{2}{3}+\right\}$, extending the known threshold results from the periodic case $\mathbb{T}_x \times \mathbb{R}_y$ to the whole space. The core innovations are twofold: First, the $\langle D_x^{-1} \rangle$ control on the initial data simultaneously resolves horizontal frequency singularities and optimizes integral indices when applying Young's convolution inequality. Second, we develop a modified multiplier $\mathcal{M}_3$ that effectively absorbs the $|D_x|^{1/3}$ derivative structure induced by the temperature equation while handling nonlinear echo cascades.
title Stability threshold of Couette flow for Boussinesq equations in $\mathbb{R}^2$
topic Analysis of PDEs
url https://arxiv.org/abs/2508.11908