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arXiv 2310.09288math.AP
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无界区域中不可压缩粘性流真空态的自由边界正则性

Free boundary regularity of vacuum states for incompressible viscous flows in unbounded domains

Christophe Prange, Jin Tan

AI总结:

本文针对全空间R^d中非齐次不可压缩Navier-Stokes方程允许真空的弱解,在初始密度仅非负有界、初始速度具额外正则性的条件下证明唯一性与正则性,并刻画真空气泡及流体斑块的自由边界演化。

摘要:

在Lions的著名著作《Mathematical topics in fluid mechanics. Incompressible models》(1996)中,证明了非齐次不可压缩Navier-Stokes方程(INS)有限能量弱解的全局存在性结果,且没有对初始密度假设正下界,因此允许真空存在。密度斑块的唯一性、正则性以及边界正则性的保持被列为开放问题。最近,Danchin和Mucha在《The incompressible Navier-Stokes equations in vacuum》(Comm. Pure Appl. Math., 72 (2019), 1351–1385)中,在流体区域为有界区域或环面的情形下,对Lions的问题取得了突破。然而,由于缺乏Poincaré型不等式,无界区域的情形仍未解决。本文在全空间情形 R^d(d=2或3)中,对于(INS)获得了Lions弱解的正则性和唯一性,其中仅假设初始密度有界且非负,并仅对初始速度附加正则性假设。特别地,我们的结果使我们能够研究嵌入不可压缩流体中的真空气泡的演化,以及嵌入真空中的均匀流体斑块的演化,这在全空间情形下回答了Lions的问题。

英文摘要:

In the well-known book of Lions [{\em Mathematical topics in fluid mechanics. Incompressible models}, 1996], global existence results of finite energy weak solutions of the inhomogeneous incompressible Navier-Stokes equations (INS) were proved without assuming positive lower bounds on the initial density, hence allowing for vacuum. Uniqueness, regularity and persistence of boundary re\-gularity of density patches were listed as open problems. A breakthrough on Lions' problems was recently made by Danchin and Mucha [The incompressible Navier-Stokes equations in vacuum, {\em Comm. Pure Appl. Math.}, 72 (2019), 1351--1385] in the case where the fluid domain is either bounded or the torus. However, the case of unbounded domains was left open because of the lack of Poincaré-type inequalities. In this paper, we obtain regularity and uniqueness of Lions' weak solutions for (INS) with \emph{only bounded and nonnegative initial density} and additional regularity only assumed for the initial velocity, in the whole-space case $\mathbb R^d$, $d=2$ or $3$. In particular, our result allows us to study the evolution of a vacuum bubble embedded in an incompressible fluid, as well as a patch of a homogeneous fluid embedded in the vacuum, which provides an answer to Lions' question in the whole-space case.

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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