arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2007.10828math.NAcs.NAmath.APmath.PR
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多尺度随机场数值均匀化的修正胞腔问题的解析和数值研究

Analytical and numerical study of a modified cell problem for the numerical homogenization of multiscale random fields

Assyr Abdulle, Doghonay Arjmand, Edoardo Paganoni

摘要:

多尺度系数偏微分方程数值均匀化的一个核心问题是均匀化系数等有效量的精确计算。计算均匀化系数需要解决局部校正问题,然后对相关局部数据进行放大。计算均匀化系数的最简单的方法是通过求解局部椭圆问题,这是已知的,从所谓的谐振误差占主导地位的所有其他错误在多尺度计算中固有的。一个更有效的建模策略,增加一个指数校正项的基础上,标准的本地椭圆问题,最近已被证明会导致指数衰减的误差界相对于本地几何的大小。与这种方法的精度和计算效率有关的问题以前已经在周期性均匀化的背景下得到了解决。本文将修正椭圆校正问题的数学和数值研究推广到随机均匀化问题。特别是,我们假设一个平稳的,遍历的微结构和i)建立适定性的校正方程,ii)分析的偏差(或系统误差)源自额外的指数校正项的模型。数值结果证实了我们的理论研究结果。

英文摘要:

A central question in numerical homogenization of partial differential equations with multiscale coefficients is the accurate computation of effective quantities, such as the homogenized coefficients. Computing homogenized coefficients requires solving local corrector problems followed by upscaling relevant local data. The most naive way of computing homogenized coefficients is by solving a local elliptic problem, which is known to suffer from the so-called resonance error dominating all other errors inherent in multiscale computations. A far more efficient modelling strategy, based on adding an exponential correction term to the standard local elliptic problem, has recently been proved to result in exponentially decaying error bounds with respect to the size of the local geometry. The questions in relation with the accuracy and computational efficiency of this approach has been previously addressed in the context of periodic homogenization. The present article concerns the extension of mathematical and numerical study of this modified elliptic corrector problem to stochastic homogenization problems. In particular, we assume a stationary, ergodic micro-structure and i) establish the well-posedness of the corrector equation, ii) analyse the bias (or the systematic error) originating from additional exponential correction term in the model. Numerical results corroborating our theoretical findings are presented.

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