arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.13445math.AP
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具有水平耗散的二维各向异性Boussinesq方程的稳定性和指数衰减

Stability and exponential decay for the 2D anisotropic Boussinesq equations with horizontal dissipation

Boqing Dong, Jiahong Wu, Xiaojing Xu, Ning Zhu

摘要:

流体静力平衡是流体力学和天体物理学中的一个重要课题。了解Boussinesq系统流体静力平衡附近扰动的稳定性有助于深入了解某些天气现象。这里重点讨论的二维Boussinesq系统是各向异性的,只涉及水平耗散和水平热扩散。由于缺乏垂向耗散,稳定性和精确的大时间行为问题是困难的。当空间域是$\mathbb R^2$时,Sobolev设置中的稳定性问题仍然是开放的。当空间域为$\mathbb T\times \mathbb R$时,本文解决了稳定性问题,并指定了精确的大时间行为的扰动。通过将速度$u$和温度$θ$分解为水平平均$(\bar u, \barθ)$和相应的振荡$(\widetilde u, \widetilde θ)$,并导出各种各向异性不等式,我们能够建立Sobolev空间$H^2$的全局稳定性.另外,我们证明了振荡$(\widetilde u, \widetilde θ)$在$H^1$中指数衰减到零,并且$(u, θ)$收敛到$(\bar u, \barθ)$ .这一结果反映了浮力驱动流体的分层现象。

英文摘要:

The hydrostatic equilibrium is a prominent topic in fluid dynamics and astrophysics. Understanding the stability of perturbations near the hydrostatic equilibrium of the Boussinesq systems helps gain insight into certain weather phenomena. The 2D Boussinesq system focused here is anisotropic and involves only horizontal dissipation and horizontal thermal diffusion. Due to the lack of the vertical dissipation, the stability and precise large-time behavior problem is difficult. When the spatial domain is $\mathbb R^2$, the stability problem in a Sobolev setting remains open. When the spatial domain is $\mathbb T\times \mathbb R$, this paper solves the stability problem and specifies the precise large-time behavior of the perturbation. By decomposing the velocity $u$ and temperature $θ$ into the horizontal average $(\bar u, \barθ)$ and the corresponding oscillation $(\widetilde u, \widetilde θ)$, and deriving various anisotropic inequalities, we are able to establish the global stability in the Sobolev space $H^2$. In addition, we prove that the oscillation $(\widetilde u, \widetilde θ)$ decays exponentially to zero in $H^1$ and $(u, θ)$ converges to $(\bar u, \barθ)$. This result reflects the stratification phenomenon of buoyancy-driven fluids.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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