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arXiv 1707.09909math.AP
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定常Euler流下的多项式混合

Polynomial mixing under a certain stationary Euler flow

Gianluca Crippa, Renato Lucà, Christian Schulze

摘要:

本文研究二维单位球上标量$ρ$与一定不可压速度场$u$的平流混合性质,这是Euler方程的定态径向解.标量$ρ$用速度场$u$求解连续性方程,我们可以用在这种设置中常用的两种不同尺度来测量~ $ρ$的混合程度,即几何混合尺度和函数混合尺度。我们开发了一个物理空间的方法,以及适合于定量分析的几何混合尺度,这原来是多项式的一个大类的初始数据的时间衰减。这扩展了以前的结果的功能混合规模,基于显式表达式的解决方案在傅立叶变量,结果也部分恢复我们的方法。

英文摘要:

We study the mixing properties of a scalar $ρ$ advected by a certain incompressible velocity field $u$ on the two dimensional unit ball, which is a stationary radial solution of the Euler equation. The scalar $ρ$ solves the continuity equation with velocity field $u$ and we can measure the degree of mixedness of~$ρ$ with two different scales commonly used in this setting, namely the geometric and the functional mixing scale. We develop a physical space approach well adapted for the quantitative analysis of the decay in time of the geometric mixing scale, which turns out to be polynomial for a large class of initial data. This extends previous results for the functional mixing scale, based on the explicit expression for the solution in Fourier variable, results that are also partially recovered by our approach.

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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