Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations

It is desirable that a numerical method is high-order accurate, compact, efficient and able to simulate purely convection problems. Most existing high-order methods for convection-diffusion-reaction equations (CDREs) either cannot simulate purely-convection problems, or reduce to first order when t...

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Main Author: Chinedu Nwaigwe
Format: Article
Language:English
Published: Western Libraries 2024-12-01
Series:Mathematics in Applied Sciences and Engineering
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Online Access:https://ojs.lib.uwo.ca/index.php/mase/article/view/20176
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author Chinedu Nwaigwe
author_facet Chinedu Nwaigwe
author_sort Chinedu Nwaigwe
collection DOAJ
description It is desirable that a numerical method is high-order accurate, compact, efficient and able to simulate purely convection problems. Most existing high-order methods for convection-diffusion-reaction equations (CDREs) either cannot simulate purely-convection problems, or reduce to first order when they can, or require larger stencil to maintain high-order accuracy. This is challenging, especially due to the convection term which can easily lead to oscillatory solutions if naively approximated. This paper proposes a spatially second-order scheme which is able to simulate purely-convection problems with high-order accuracy on minimal stencil. Our idea is based on non-standard central discretization of the convection term. We first discretize the diffusion term in both space and time but discretize the convection term in space only. Next, the semi-discrete convection term is split into positive and negative parts. Transport coefficients are evaluated explicitly in time while different spatial operators are discretized either implicitly or explicitly such that positivity of canonical form is guaranteed. This led to a second-order scheme with all the above desirable properties. Under smoothness assumptions consistency is proved, discrete maximum principle is used to derived two-sided bounds on the numerical solution, and convergence is proved in maximum norm. Several numerical examples are provided to verify the second-order spatial accuracy, convergence and the ability to simulate purely convection problems.
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spelling doaj-art-890366980aab4b229c91a6343901cd6e2025-01-03T18:35:34ZengWestern LibrariesMathematics in Applied Sciences and Engineering2563-19262024-12-015410.5206/mase/20176Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equationsChinedu Nwaigwe0Rivers State University It is desirable that a numerical method is high-order accurate, compact, efficient and able to simulate purely convection problems. Most existing high-order methods for convection-diffusion-reaction equations (CDREs) either cannot simulate purely-convection problems, or reduce to first order when they can, or require larger stencil to maintain high-order accuracy. This is challenging, especially due to the convection term which can easily lead to oscillatory solutions if naively approximated. This paper proposes a spatially second-order scheme which is able to simulate purely-convection problems with high-order accuracy on minimal stencil. Our idea is based on non-standard central discretization of the convection term. We first discretize the diffusion term in both space and time but discretize the convection term in space only. Next, the semi-discrete convection term is split into positive and negative parts. Transport coefficients are evaluated explicitly in time while different spatial operators are discretized either implicitly or explicitly such that positivity of canonical form is guaranteed. This led to a second-order scheme with all the above desirable properties. Under smoothness assumptions consistency is proved, discrete maximum principle is used to derived two-sided bounds on the numerical solution, and convergence is proved in maximum norm. Several numerical examples are provided to verify the second-order spatial accuracy, convergence and the ability to simulate purely convection problems. https://ojs.lib.uwo.ca/index.php/mase/article/view/20176Convection-diffusion equations, nonlinear coefficients, two-sided bounds, experimental order of convergence, consistency, freezing coefficients.
spellingShingle Chinedu Nwaigwe
Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
Mathematics in Applied Sciences and Engineering
Convection-diffusion equations, nonlinear coefficients, two-sided bounds, experimental order of convergence, consistency, freezing coefficients.
title Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
title_full Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
title_fullStr Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
title_full_unstemmed Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
title_short Compact scheme with two-sided estimates for nonlinear convection-diffusion-reaction equations
title_sort compact scheme with two sided estimates for nonlinear convection diffusion reaction equations
topic Convection-diffusion equations, nonlinear coefficients, two-sided bounds, experimental order of convergence, consistency, freezing coefficients.
url https://ojs.lib.uwo.ca/index.php/mase/article/view/20176
work_keys_str_mv AT chinedunwaigwe compactschemewithtwosidedestimatesfornonlinearconvectiondiffusionreactionequations