论文标题

2D对流Brinkman-Forchheimer方程无界域的渐近分析:全球吸引子和上半强度

Asymptotic analysis of the 2D convective Brinkman-Forchheimer equations in unbounded domains: Global attractors and upper semicontinuity

论文作者

Mohan, Manil T.

论文摘要

在这项工作中,我们对二维对流Brinkman-Forchheimer(CBF)方程进行了渐近分析,该方程表征了在饱和多孔培养基中不可压缩流体流动的运动。我们确定了有界(使用紧凑的嵌入)和庞加莱域(使用渐近紧凑型特性)中的全球吸引子的存在。在Poincaré域中,还以$ R = 1,2 $和3美元的价格,还获得了Hausdorff的估计以及全球吸引子的分形维度。然后,我们显示了2D CBF方程的全球吸引子的上半接入性。我们考虑了一个简单连接,有界和平滑子域的扩展顺序,$ω_m$ $ $ $ $ $ω$,使得$ω_m\toΩ$ to $ m \ to \ to \ infty $。如果$ \ MATHSCR {a} _m $和$ \ MATHSCR {a} $是2D CBF方程的全球吸引者,分别对应于$ω$和$ω_m$,那么我们向大型$ M $ hober表明,全球吸引者$ \ sathscr {a} _m $ en} _m $ en} _M $ \ Mathscr {a})$ \ \ \ m rathscr {A} $。 CBF方程中Darcy项的存在有助于我们在一般无界域中获得上述结果。最后,我们讨论了与有限域中的2D CBF方程相关的半群的准稳定性属性,并确定了有限分形维尺寸全局以及$ r \ in [1,\ infty)$的指数吸引子的存在。

In this work, we carry out the asymptotic analysis of the two dimensional convective Brinkman-Forchheimer (CBF) equations, which characterize the motion of incompressible fluid flows in a saturated porous medium. We establish the existence of a global attractor in both bounded (using compact embedding) and Poincaré domains (using asymptotic compactness property). In Poincaré domains, for $r=1,2$ and $3$, the estimates for Hausdorff as well as fractal dimensions of the global attractors are also obtained. We then show an upper semicontinuity of global attractors for the 2D CBF equations. We consider an expanding sequence of simply connected, bounded and smooth subdomains $Ω_m$ of the Poincaré domain $Ω$ such that $Ω_m\toΩ$ as $m\to\infty$. If $\mathscr{A}_m$ and $\mathscr{A}$ are the global attractors of the 2D CBF equations corresponding to $Ω$ and $Ω_m$, respectively, then we show that for large enough $m$, the global attractor $\mathscr{A}_m$ enters into any neighborhood $\mathcal{U}(\mathscr{A})$ of $\mathscr{A}$. The presence of Darcy term in the CBF equations helps us to obtain the above mentioned results in general unbounded domains also. Finally, we discuss about the quasi-stability property of the semigroup associated with the 2D CBF equations in bounded domains and establish the existence of finite fractal dimensional global as well as exponential attractors for $r\in[1,\infty)$.

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