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arXiv 1606.02668math.NAcs.NA
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Cahn-Hilliard-Navier-Stokes系统第二阶有限元方法的收敛性分析与误差估计

Convergence Analysis and Error Estimates for a Second Order Accurate Finite Element Method for the Cahn-Hilliard-Navier-Stokes System

Louisiana State University(路易斯安那州立大学);The University of Massachusetts(麻省大学);Florida State University(佛罗里达州立大学);The University of Tennessee(田纳西大学)

Amanda E. Diegel, Cheng Wang, Xiaoming Wang, Steven M. Wise

AI总结:

本文提出一种新的第二阶时间混合有限元格式,用于求解具有匹配密度的Cahn-Hilliard-Navier-Stokes方程,结合改进的Crank-Nicholson方法和Adams-Bashforth外推,证明了该格式在能量稳定性及变量收敛性方面具有最优收敛率。

摘要:

本文提出了一种新的第二阶时间混合有限元格式,用于求解具有匹配密度的Cahn-Hilliard-Navier-Stokes方程。该格式结合了标准的第二阶Crank-Nicholson方法用于Navier-Stokes方程,以及对Cahn-Hilliard方程Crank-Nicholson方法的改进。特别地,包含第二阶Adams-Bashforth外推和梯形法则,以保持Cahn-Hilliard方程固有的能量稳定性。我们证明了该格式相对于PDE系统的修改连续自由能是无条件能量稳定的。具体来说,离散的相变量在$\ell^\infty \left(0,T;L^\infty\right)$中被证明是有界的,而离散的化学势在$\ell^\infty \left(0,T;L^2\right)$中被证明是有界的,对于任意的时间和空间步长,在二维和三维空间中以及对于任意有限的最终时间$T$。我们随后证明了这些变量以及流体速度在二维和三维空间中以最优速率收敛于适当的能量范数中。

英文摘要:

In this paper, we present a novel second order in time mixed finite element scheme for the Cahn-Hilliard-Navier-Stokes equations with matched densities. The scheme combines a standard second order Crank-Nicholson method for the Navier-Stokes equations and a modification to the Crank-Nicholson method for the Cahn-Hilliard equation. In particular, a second order Adams-Bashforth extrapolation and a trapezoidal rule are included to help preserve the energy stability natural to the Cahn-Hilliard equation. We show that our scheme is unconditionally energy stable with respect to a modification of the continuous free energy of the PDE system. Specifically, the discrete phase variable is shown to be bounded in $\ell^\infty \left(0,T;L^\infty\right)$ and the discrete chemical potential bounded in $\ell^\infty \left(0,T;L^2\right)$, for any time and space step sizes, in two and three dimensions, and for any finite final time $T$. We subsequently prove that these variables along with the fluid velocity converge with optimal rates in the appropriate energy norms in both two and three dimensions.

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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