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Yahya Alnashri

Publications and source records attributed to Yahya Alnashri.

13 recordsLinked to original sources
arXiv2025

Error Estimates of Generic Discretisation of Reaction-Diffusion System with Constraints

In this paper, we study a parabolic reaction diffusion system with constraints that model biofilm growth. Within a unified framework encompassing multiple numerical schemes, we derive the first general convergence rates for approximating this model using both conforming and non conforming discretisation methods. Under standard assumptions on the time discretisation, we establish the existence and uniqueness of the discrete solution. Numerical experiments are conducted using a mixed finite volume scheme that fits within the proposed unified framework. A test case with an analytical solution is designed to confirm our theoretical convergence rates.

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arXiv2025

Error Estimates for Non Conforming Discretisation of Time-dependent Convection-Diffusion-Reaction Model

We use a generic framework, namely the gradient discretisation method (GDM), to propose a unified numerical analysis for general time-dependent convection-diffusion-reaction models. We establish novel results for convergence rates of numerical approximations of such models under reasonable assumptions on exact solutions, and prove the existence and uniqueness of the approximate solution for suitably small time steps. The main interest of our results lies in covering several approximation methods and various applications of the considered model such as the generalised Burgers-Fisher (GBF) and the generalised Burgers-Huxley (GBH) models. Numerical tests based on the hybrid mimetic mixed (HMM) method for the GBF model are performed on various types of general meshes to examine the accuracy of the proposed gradient scheme. The results confirm our theoretical rates of convergence, even on mesh with extreme distortions.

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arXiv2025

General Error Estimates of Non Conforming Approximation of System of Reaction-Diffusion Equations

This paper aims to establish a first general error estimate for numerical approximations of the system of reaction-diffusion equations (SRDEs), using reasonable regularity assumptions on the exact solutions. We employ the gradient discretisation method (GDM) to discretise the system and prove the existence and uniqueness of the approximate solutions. The analysis provided here is not limited to specific reaction functions, and it is applicable to all conforming and non-conforming schemes fitting within the GDM framework. As an application, we present numerical results based on a finite volume method.

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arXiv2024

Generic Numerical Analysis of Stochastic Reaction Diffusion Model with applications in excitable media

The stochastic reaction-diffusion model driven by a multiplicative noise is examined. We construct the gradient discretisation method (GDM), an abstract framework combining several numerical method families. The paper provides the discretisation and proves the convergence of the approximate schemes using a compactness argument that works under natural assumptions on data. We also investigate, using a finite volume method, known as the hybrid mixed mimetic (HMM) approach, the effects of multiplicative noise on the dynamics of the travelling waves in the excitable media displayed by the model. Particularly, we consider how sufficiently high noise can cause waves to backfire or fail to propagate.

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arXiv2023

A new Discrete Analysis Of Fourth Order Elliptic Variational Inequalities

This paper applies the gradient discretisation method (GDM) for fourth order elliptic variational inequalities. The GDM provides a new formulation of error estimates and a complete convergence analysis of several numerical methods. We show that the convergence is unconditional. Classical assumptions on data are only sufficient to establish the convergence results. These results are applicable for all schemes fall in the framework of GDM.

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arXiv2021

Convergence Analysis For Non Linear System Of Parabolic Variational Inequalities

This work aims to provide a comprehensive and unified numerical analysis for non linear system of parabolic variational inequalities (PVIs) subject to Dirichlet boundary condition. This analysis enables us to establish an existence of the exact solution to the considered model and to prove the convergence for the approximate solution and its approximate gradient. Our results are applicable for several conforming and non conforming numerical schemes.

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arXiv2021

The gradient discretisation method for the chemical reactions of biochemical systems

We consider a biochemical model that consists of a system of partial differential equations based on reaction terms and subject to non--homogeneous Dirichlet boundary conditions. The model is discretised using the gradient discretisation method (GDM) which is a framework covering a large class of conforming and non conforming schemes. Under classical regularity assumptions on the exact solutions, the GDM enables us to establish the existence of the model solutions in a weak sense, and strong convergence for the approximate solution and its approximate gradient. Numerical test employing a finite volume method is presented to demonstrate the behaviour of the solutions to the model.

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arXiv2020

A General Error Estimate For Parabolic Variational Inequalities

The gradient discretisation method (GDM) is a generic framework designed recently, as a discretise in spatial space, to partial differential equations. This paper aims to use the GDM to establish a first general error estimate for numerical approximations of parabolic obstacle problems. This gives the convergence rates of several well--known conforming and non conforming numerical methods. Numerical experiments based on the hybrid finite volume method are provided to verify the theoretical results.

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arXiv2020

A gradient Discretisation Method For Anisotropic Reaction Diffusion Models with applications to the dynamics of brain tumours

A gradient discretisation method (GDM), Gradient schemes, Convergence analysis, Existence of weak solutions, Anisotropic reaction diffusion models, Dirichlet and Neumann boundary conditions, Non conforming finite element methods, Finite volume schemes, Hybrid mixed mimetic (HMM) method, Crouzeix--Raviart scheme, Brain tumour dynamics, Fractional anisotropy.

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arXiv2020

A unified Analysis For Reaction Diffusion Models With Application To The Spiral Waves Dynamic Of The Barkley Model

Applying the gradient discretisation method (GDM), the paper develops a comprehensive numerical analysis for the reaction diffusion model. Using only three properties, this analysis provides convergence results for several conforming and non-conforming numerical schemes that align with the GDM. As an application of this analysis, the hybrid mimetic mixed (HMM) method for the reaction diffusion model is designed and its convergence established. Numerical experiments using the HMM method are presented to facilitate study of the creation of spiral waves in the Barkley model and the ways in which the waves behave when interacting with the boundaries of their generating medium

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arXiv2018

A gradient discretisation method to analyse numerical schemes for non-linear variational inequalities, application to the seepage problem

Using the gradient discretisation method (GDM), we provide a complete and unified numerical analysis for non-linear variational inequalities (VIs) based on Leray--Lions operators and subject to non-homogeneous Dirichlet and Signorini boundary conditions. This analysis is proved to be easily extended to the obstacle and Bulkley models, which can be formulated as non-linear VIs. It also enables us to establish convergence results for many conforming and nonconforming numerical schemes included in the GDM, and not previously studied for these models. Our theoretical results are applied to the hybrid mimetic mixed method (HMM), a family of schemes that fit into the GDM. Numerical results are provided for HMM on the seepage model, and demonstrate that, even on distorted meshes, this method provides accurate results.

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arXiv2016

Gradient schemes for the Signorini and the obstacle problems, and application to hybrid mimetic mixed methods

Gradient schemes is a framework which enables the unified convergence analysis of many different methods -- such as finite elements (conforming, non-conforming and mixed) and finite volumes methods -- for $2^{\rm nd}$ order diffusion equations. We show in this work that the gradient schemes framework can be extended to variational inequalities involving mixed Dirichlet, Neumann and Signorini boundary conditions. This extension allows us to provide error estimates for numerical approximations of such models, recovering known convergence rates for some methods, and establishing new convergence rates for schemes not previously studied for variational inequalities. The general framework we develop also enables us to design a new numerical method for the obstacle and Signorini problems, based on hybrid mimetic mixed schemes. We provide numerical results that demonstrate the accuracy of these schemes, and confirm our theoretical rates of convergence.

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