Generalized multiscale approximation of a mixed finite element method with velocity elimination for Darcy flow in fractured porous media

Zhengkang He, Huangxin Chen, Jie Chen*, Zhangxin Chen*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

In this paper, we propose a multiscale method for solving the Darcy flow of a single-phase fluid in two-dimensional fractured porous media. We consider a discrete fracture-matrix (DFM) model that treats fractures as one-dimensional objects, and flows in both the matrix and fractures respect the Darcy's law. A multipoint flux mixed finite element (MFMFE) method with the broken Raviart–Thomas (RT[Formula presented]) element and the trapezoidal quadrature rule is employed to approximate the matrix velocity and pressure, which results in a block diagonal, symmetric and positive definite mass matrix for the matrix velocity on general quadrilateral grids; the one-dimensional RT0 mixed finite element method with the one-dimensional trapezoidal quadrature rule is exploited to approximate the fracture velocity and pressure, which leads to a diagonal and positive definite mass matrix for the fracture velocity in each single fracture. All these features of the obtained mass matrices allow for velocity elimination. Multiscale basis functions are constructed for the two-dimensional matrix pressure following the generalized multiscale finite element method (GMsFEM) framework to capture the fine-scale information of heterogeneous fractured porous media and effectively reduce the degrees of freedom for the matrix pressure, while fine-grid basis functions are utilized for the one-dimensional fracture pressure in fractures. Various numerical tests with the oversampling technique for different fracture distributions are performed to show that the proposed multiscale method is effective and able to provide good approximations for the fine-grid solution.

Original languageEnglish
Article number113846
JournalComputer Methods in Applied Mechanics and Engineering
Volume381
DOIs
Publication statusPublished - 1 Aug 2021

Keywords

  • DFM models
  • Darcy flow
  • Fractured porous media
  • MFMFE methods
  • Mixed GMsFEM
  • Multiscale methods

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