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arXiv 0910.1386math-phmath.MP
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三维Navier-Stokes-Voigt方程的不变测度及其Navier-Stokes极限

Invariant measures for the 3D Navier-Stokes-Voigt equations and their Navier-Stokes limit

Fabio Ramos, Edriss S. Titi

摘要:

粘弹性不可压缩流体的Navier-Stokes-Voigt模型最近被提出来作为三维纳维-斯托克斯方程的正则化,用于直接数值模拟。除了运动粘度参数$ν>0$之外,该模型还具有正则化参数$α> 0$,即给定的长度尺度参数,因此$\frac{α^2}ν$是粘弹性流体的弛豫时间。在这项工作中,我们得到了与三维Navier-Stokes-Voigt方程的解相关的不变测度的几个统计性质。此外,我们证明了,对于固定的粘度,$ν>0$,作为正则化参数$α$趋于零,存在一个子序列的概率不变的措施,收敛,在适当的意义下,一个强平稳的统计解的三维纳维-斯托克斯方程,这是平稳统计解概念的正则化版本-Foias介绍和研究的不变测度概念的推广。这一事实支持了早期的数值观测,并提供了额外的证据,即对于正则化参数$α$的小值,Navier-Stokes-Voigt模型确实可以被认为是通过直接数值模拟来研究三维纳维-斯托克斯方程和湍流的统计特性的模型。

英文摘要:

The Navier-Stokes-Voigt model of viscoelastic incompressible fluid has been recently proposed as a regularization of the three-dimensional Navier-Stokes equations for the purpose of direct numerical simulations. Besides the kinematic viscosity parameter, $ν>0$, this model possesses a regularizing parameter, $α> 0$, a given length scale parameter, so that $\frac{α^2}ν$ is the relaxation time of the viscoelastic fluid. In this work, we derive several statistical properties of the invariant measures associated with the solutions of the three-dimensional Navier-Stokes-Voigt equations. Moreover, we prove that, for fixed viscosity, $ν>0$, as the regularizing parameter $α$ tends to zero, there exists a subsequence of probability invariant measures converging, in a suitable sense, to a strong stationary statistical solution of the three-dimensional Navier-Stokes equations, which is a regularized version of the notion of stationary statistical solutions - a generalization of the concept of invariant measure introduced and investigated by Foias. This fact supports earlier numerical observations, and provides an additional evidence that, for small values of the regularization parameter $α$, the Navier-Stokes-Voigt model can indeed be considered as a model to study the statistical properties of the three-dimensional Navier-Stokes equations and turbulent flows via direct numerical simulations.

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