Effect of nonlinear sorption on multispecies radionuclide transport in a coupled fracture-matrix system with variable fracture aperture: a numerical study

Abstract

A one-dimensional numerical analysis on multispecies radionuclide transport in a single-horizontal coupled fracture-matrix system has been performed. Analysis considering linear and nonlinear adsorption cases with linear, Langmuir, and Freundlich adsorption models has been carried out. The results indicate that there is a significant change in the spatial distribution of radionuclides in a coupled fracture-matrix system when a nonlinear adsorption isotherm is considered as compared to the simplified linear sorption isotherm. Sensitivity analysis of Langmuir constant and Freundlich exponent has been performed, and the numerical results indicate that the behavior of radionuclide transport is strongly influenced by these nonlinear sorption isotherm parameters. In addition, an attempt has been made to consider the variation of fracture aperture thickness along its flow direction by introducing logarithmic distribution. A clear distinction in the spatial distribution of radionuclide concentration was observed when variable fracture aperture is considered as opposed to the conventional parallel plate model with a constant fracture aperture thickness. Further, the results suggest that there is an enhanced retardation of radionuclides within the high permeable fracture with varying fracture aperture.

Fully Implicit Form of Differential Quadrature Method for Multi-Species Solute Transport in Porous Media

“…Details of the problems for the first and second cases, including retardation coefficient (R m ), decay coefficient (𝜆 ), initial and boundary conditions, etc., are described in Table (1). It is worthwhile to mention that in tables and figures below, the first and second case studies are referred to as the analytical results of dimensionless concentration for the three The results of numerical experiments for the first and second test cases are summarized in figures ( 1) and ( 2) and Tables (2-4).…”

Physics-Informed Neural Networks with Periodic Activation Functions for Solute Transport in Heterogeneous Porous Media

“…For example, Zhang et al [11] suggested a 1D model based on FEM for multi-component solute transport in saturated soil. Bagalkot and Suresh Kumar [12] presented a 1D numerical evaluation of the FDM for multi-species radionuclide transport in a single horizontally coupled fracture-matrix system. Mostaghimi et al [13] and Maheshwari et al [14] investigated the effect of pore structure heterogeneity on reactive transport using a 3D pore scale model based on FVM.…”

A Numerical Model with Finite Difference Schemes for Multi-Species Solute Transport in Porous Media

“…Torlapati (2013) proposed a multi-component reactive transport model by using explicit forms of backward difference FDM, total variation diminishing schemes, and fully implicit approaches to predict the fate and transport of biochemical and geochemical reactive transport problems in a 1D condition. Bagalkot and Kumar (2015) introduced a 1D numerical assessment with FDM for multispecies radionuclide transport in a single-horizontal coupled fracture-matrix system. Sharma et al (2016) investigated the impact of distance-dependent dispersion on multispecies solute transport process with upwind-and central-difference approaches of implicit FDM, as well as constant, linear, and exponential dispersivity functions.…”