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arXiv 2409.01142math.AP
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可压缩 Couette 流的非线性稳定性阈值

Nonlinear stability threshold for compressible Couette flow

Feimin Huang, Rui Li, Lingda Xu

AI总结:

本文针对二维可压缩 Navier-Stokes 方程的高 Reynolds 数 Couette 流,利用模态分解、反导数、扩散波、加权能量及 Fourier 乘子等方法,证明非线性稳定性、增强耗散与稳定性阈值。

摘要:

本文研究无限长平环面 $\Torus\times\R$ 上二维可压缩 Navier-Stokes 方程(N-S)的 Couette 流。与不可压缩流相比,可压缩 Couette 流具有更强的抬升效应和更弱的耗散。据我们所知,迄今为止尚无关于高 Reynolds 数情形下非线性稳定性的工作,文献 \cite{ADM2021,ZZZ2022} 中仅已知线性稳定性。本文研究高 Reynolds 数下 Sobolev 空间中二维可压缩 Couette 流的非线性稳定性。此外,我们还展示了可压缩 Couette 流的增强耗散现象和稳定性阈值。首先,我们将扰动分解为零模和非零模,并分别得到这两个分量的两个系统。与文献 \cite{ADM2021,ZZZ2022} 不同,我们使用反导数技术研究零模系统。我们引入一种扩散波以消除零模的多余质量,并沿特征线构造耦合扩散波,以改善误差项所得的时间衰减率,并导出一个新的积分系统 \cref{anti}。其次,我们观察到新系统 \cref{anti} 中的一种抵消,从而使抬升效应减弱。第三,通过加权能量方法和关于热核的加权不等式 \cite{HLM2010},得到零模的大时间行为。此外,借助 Fourier 乘子方法,我们能够通过交换子估计展示非零模的增强耗散现象,以避免导数损失。最后,我们通过能量方法完成高阶导数估计,以闭合先验假设,并展示稳定性阈值。

英文摘要:

This paper concerns the Couette flow for 2-D compressible Navier-Stokes equations (N-S) in an infinitely long flat torus $\Torus\times\R$. Compared to the incompressible flow, the compressible Couette flow has a stronger lift-up effect and weaker dissipation. To the best of our knowledge, there has been no work on the nonlinear stability in the cases of high Reynolds number until now and only linear stability was known in \cite{ADM2021,ZZZ2022}.In this paper, we study the nonlinear stability of 2-D compressible Couette flow in Sobolev space at high Reynolds numbers. Moreover, we also show the enhanced dissipation phenomenon and stability threshold for the compressible Couette flow. First, We decompose the perturbation into zero and non-zero modes and obtain two systems for these components, respectively. Different from \cite{ADM2021,ZZZ2022}, we use the anti-derivative technique to study the zero-mode system. We introduce a kind of diffusion wave to remove the excessive mass of the zero-modes and construct coupled diffusion waves along characteristics to improve the resulting time decay rates of error terms and derive a new integrated system \cref{anti}. Secondly, we observe a cancellation with the new system \cref{anti} so that the lift-up effect is weakened. Thirdly, the large time behavior of the zero-modes is obtained by the weighted energy method and a weighted inequality on the heat kernel \cite{HLM2010}.In addition, with the help of the Fourier multipliers method, we can show the enhanced dissipation phenomenon for the non-zero modes by commutator estimates to avoid loss of derivatives. Finally, we complete the higher-order derivative estimates to close the a priori assumptions by the energy method and show the stability threshold.

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