论文标题

多孔多孔介质中多尺度多牙的有效脱钩方案

Efficient decoupling schemes for multiscale multicontinuum problems in fractured porous media

论文作者

Vasilyeva, Maria

论文摘要

我们考虑了描述断裂多孔介质流动的方程式耦合系统。为了描述这种类型的问题,使用了多牙和多尺度方法。因为在多通用模型中,每个连续体的渗透性都有显着差异,因此每次迭代时所得线性方程式的解决方案都需要大量迭代。提出的去耦技术将每个连续体的方程式分开,这些方程可以分别解决,从而导致具有较小系统和更快的解决方案的更有效的计算算法。该方法基于按时间半近似近似的操作员的加性表示,其中连续耦合部分是从上一个时间层取的。我们在有限体积近似的足够细网格上应用,分析和数值研究了裂缝多孔介质中经典多孔术问题的分离方案。我们表明,解耦方案是稳定,准确且计算上有效的。接下来,我们使用非局部多通用(NLMC)方法扩展并研究了这种方法的多尺度近似方法。在NLMC近似中,我们采用相同的连续分离方法构建了相似的解耦方案。在二维公式中,提出了有关两个和三核的模型问题的数值研究。

We consider the coupled system of equations that describe flow in fractured porous media. To describe such types of problems, multicontinuum and multiscale approaches are used. Because in multicontinuum models, the permeability of each continuum has a significant difference, a large number of iterations is required for the solution of the resulting linear system of equations at each time iteration. The presented decoupling technique separates equations for each continuum that can be solved separately, leading to a more efficient computational algorithm with smaller systems and faster solutions. This approach is based on the additive representation of the operator with semi-implicit approximation by time, where the continuum coupling part is taken from the previous time layer. We apply, analyze and numerically investigate decoupled schemes for classical multicontinuum problems in fractured porous media on sufficiently fine grids with finite volume approximation. We show that the decoupled schemes are stable, accurate, and computationally efficient. Next, we extend and investigate this approach for multiscale approximation on the coarse grid using the nonlocal multicontinuum (NLMC) method. In NLMC approximation, we construct similar decoupled schemes with the same continuum separation approach. A numerical investigation is presented for model problems with two and three-continuum in the two-dimensional formulation.

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