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arXiv 1610.04772math.AP
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多孔介质方程在外部区域的准域渐近性。临界二维情形

Near field asymptotics for the porous medium equation in exterior domains. The critical two-dimensional case

Carmen Cortázar, Fernando Quirós, Noemí Wolanski

摘要:

我们考虑二维外区域中的多孔介质方程,该区域不包括一个孔洞,其边界上的Dirichlet数据为零。Gilding和Goncerzewicz在[Gilding-Goncerzewicz-2007]中证明,在远场尺度下,$x=ξt^{\frac1{2m}}/(\log t)^{\frac{m-1}{2m}}$,$ξ\ne 0$,具有可积和紧支持的初始数据的该问题的解表现为具有可变质量的方程的瞬时点源解,该方程以精确的方式衰减到0,由初始数据和孔确定。然而,他们的结果并没有说太多的行为时,$|x|=o\big(t^{\frac1{2m}}/(\log t)^{\frac{m-1}{2m}}\big)$,在所谓的准域规模,除了解决方案是$o\big((t\log t)^{-\frac1m}\big)$有。特别是,它不给一个尖锐的衰减率,也不是一个非平凡的渐近配置文件,紧集。本文刻画了这种尺度下的大时间行为,从而完善了[Gilding-Goncerzewicz-2007]的结果.

英文摘要:

We consider the porous medium equation in an exterior two-dimensional domain which excludes a hole, with zero Dirichlet data on its boundary. Gilding and Goncerzewicz proved in [Gilding-Goncerzewicz-2007] that in the far field scale, $x=ξt^{\frac1{2m}}/(\log t)^{\frac{m-1}{2m}}$, $ξ\ne 0$, solutions to this problem with an integrable and compactly supported initial data behave as an instantaneous point-source solution for the equation with a variable mass that decays to 0 in a precise way, determined by the initial data and the hole. However, their result does not say much about the behavior when $|x|=o\big(t^{\frac1{2m}}/(\log t)^{\frac{m-1}{2m}}\big)$, in the so called near field scale, except that the solution is $o\big((t\log t)^{-\frac1m}\big)$ there. In particular, it does not give a sharp decay rate, neither a nontrivial asymptotic profile, on compact sets. In this paper we characterize the large time behavior in such scale, thus completing the results of [Gilding-Goncerzewicz-2007].

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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