Linear, decoupled, second-order and structure-preserving scheme for Carreau fluid equations coupled with steric Poisson-Nernst-Planck model

Fuente: arXiv
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Main Authors: Zhu, Wenxing, Pan, Mingyang, He, Dongdong
Format: Preprint
Published: 2025
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author Zhu, Wenxing
Pan, Mingyang
He, Dongdong
author_facet Zhu, Wenxing
Pan, Mingyang
He, Dongdong
contents In this paper, to study ionic steric effects, we present a linear, decoupled, second-order accurate in time and structure-preserving scheme with finite element approximations for Carreau fluid equations coupled with steric Poisson-Nernst-Planck (SPNP) model. The logarithmic transformation for the ion concentration is used to preserve positivity property. To deal with the nonlinear coupling terms in fluid equation, a nonlocal auxiliary variable with respect to the free energy of SPNP equations and its associated ordinary differential equation are introduced. The obtained system is equivalent to the original system. The fully discrete scheme is proved to be mass conservative, positivity-preserving for ion concentration and energy dissipative at discrete level. Some numerical simulations are provided to demonstrate its stability and accuracy. Moreover, the ionic steric effects are numerically investigated.
format Preprint
id arxiv_https___arxiv_org_abs_2509_01270
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Linear, decoupled, second-order and structure-preserving scheme for Carreau fluid equations coupled with steric Poisson-Nernst-Planck model
Zhu, Wenxing
Pan, Mingyang
He, Dongdong
Numerical Analysis
In this paper, to study ionic steric effects, we present a linear, decoupled, second-order accurate in time and structure-preserving scheme with finite element approximations for Carreau fluid equations coupled with steric Poisson-Nernst-Planck (SPNP) model. The logarithmic transformation for the ion concentration is used to preserve positivity property. To deal with the nonlinear coupling terms in fluid equation, a nonlocal auxiliary variable with respect to the free energy of SPNP equations and its associated ordinary differential equation are introduced. The obtained system is equivalent to the original system. The fully discrete scheme is proved to be mass conservative, positivity-preserving for ion concentration and energy dissipative at discrete level. Some numerical simulations are provided to demonstrate its stability and accuracy. Moreover, the ionic steric effects are numerically investigated.
title Linear, decoupled, second-order and structure-preserving scheme for Carreau fluid equations coupled with steric Poisson-Nernst-Planck model
topic Numerical Analysis
url https://arxiv.org/abs/2509.01270