Operator Splitting and Local Time-Stepping Methods for Transport Problems in Fractured Porous Media

Operator Splitting and Local Time-Stepping Methods for Transport Problems in Fractured Porous Media

Year:    2023

Author:    Phuoc-Toan Huynh, Yanzhao Cao, Thi-Thao-Phuong Hoang

Communications in Computational Physics, Vol. 34 (2023), Iss. 5 : pp. 1215–1246

Abstract

This paper is concerned with efficient numerical methods for the advection-diffusion equation in a heterogeneous porous medium containing fractures. A dimensionally reduced fracture model is considered, in which the fracture is represented as an interface between subdomains and is assumed to have larger permeability than the surrounding area. We develop three global-in-time domain decomposition methods coupled with operator splitting for the reduced fracture model, where the advection and the diffusion are treated separately by different numerical schemes and with different time steps. Importantly, smaller time steps can be used in the fracture-interface than in the subdomains. The first two methods are based on the physical transmission conditions, while the third one is based on the optimized Schwarz waveform relaxation approach with Ventcel-Robin transmission conditions. A discrete space-time interface system is formulated for each method and is solved iteratively and globally in time. Numerical results for two-dimensional problems with various Péclet numbers and different types of fracture are presented to illustrate and compare the convergence and accuracy in time of the proposed methods with local time stepping.

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Journal Article Details

Publisher Name:    Global Science Press

Language:    English

DOI:    https://doi.org/10.4208/cicp.OA-2022-0187

Communications in Computational Physics, Vol. 34 (2023), Iss. 5 : pp. 1215–1246

Published online:    2023-01

AMS Subject Headings:    Global Science Press

Copyright:    COPYRIGHT: © Global Science Press

Pages:    32

Keywords:    Domain decomposition reduced fracture model operator splitting nonconforming time grids time-dependent Steklov-Poincaré operator optimized Schwarz waveform relaxation.

Author Details

Phuoc-Toan Huynh

Yanzhao Cao

Thi-Thao-Phuong Hoang