scholarly journals Identifying an Unknown Coefficient in the Reaction-Diffusion Equation Using He’s VIM

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
F. Parzlivand ◽  
A. M. Shahrezaee
Keyword(s):  
Unknown Parameter ◽  
Reaction Diffusion ◽  
Variational Iteration Method ◽  
Main Property ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Reaction Diffusion Equation ◽  
Unknown Coefficient ◽  
Initial Boundary Value ◽  
Inverse Heat Problem

An inverse heat problem of finding an unknown parameter p(t) in the parabolic initial-boundary value problem is solved with variational iteration method (VIM). For solving the discussed inverse problem, at first we transform it into a nonlinear direct problem and then use the proposed method. Also an error analysis is presented for the method and prior and posterior error bounds of the approximate solution are estimated. The main property of the method is in its flexibility and ability to solve nonlinear equation accurately and conveniently. Some examples are given to illustrate the effectiveness and convenience of the method.

On a singular initial-boundary-value problem for a reaction-diffusion equation arising from a simple model of isothermal chemical autocatalysis

1992 ◽  
Vol 437 (1901) ◽  
pp. 657-671 ◽  
Keyword(s):  
Simple Model ◽  
Diffusion Equation ◽  
Boundary Value Problem ◽  
Rate Constant ◽  
Boundary Value ◽  
Reaction Diffusion ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Reaction Diffusion Equation ◽  
Initial Boundary Value

In this paper we examine the evolution that occurs when a localized input of an autocatalyst B is introduced into an expanse of a reactant A. The reaction is autocatalytic of order p,so A -> B at rate k [A] [B] p with rate constant k . We examine the case when 0 < p < 1, with p>/ 1 having been examined by Needham & Merkin (Phil. Trans. R. Soc. Lond. A 337, 261—274 (1991)). In particular, we show that the fully reacted state is not achieved (as t-> oo) via the propagation of a travelling wavefront (as for p>/ 1) but is approached uniformly in space as t-00.

scholarly journals THE REACTION-DIFFUSION MODEL OF BACTERIA COMMUNICATION UNDER VARIATION IN THE LAW OF POPULATION GROWTH

2021 ◽  
pp. 14-23
Author(s):  
Shuai Yixuan ◽  
◽  
Alexey Pavlovich Khmelev ◽  
Anna Gennadievna Maslovskaya ◽  
◽  
...  
Keyword(s):  
Reaction Diffusion ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Communication Process ◽  
Reaction Diffusion Equation ◽  
Bacterial Communication ◽  
Reaction Diffusion Model ◽  
Implicit Finite Difference Scheme ◽  
The Law ◽  
Initial Boundary Value

The paper proposes a modification of the mathematical model of the bacterial communication process based on using the law of multiphase dynamics of changes in the microorganisms number. The model is described as an initial-boundary value problem for an evolutionary «reaction – diffusion» equation. An implicit finite-difference scheme is derived for the numerical solution of an applied problem. The results of computational experiments are discussed.

Numerical Method for Singularly Perturbed Parabolic Equations in Unbounded Domains in the Case of Solutions Growing at Infinity

2009 ◽  
Vol 9 (1) ◽  
pp. 100-110
Author(s):  
G. I. Shishkin
Keyword(s):  
Boundary Layer ◽  
Boundary Value Problem ◽  
Boundary Value ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Singularly Perturbed ◽  
Reaction Diffusion Equation ◽  
Maximum Norm ◽  
Lateral Part ◽  
Initial Boundary Value

AbstractAn initial-boundary value problem is considered in an unbounded do- main on the x-axis for a singularly perturbed parabolic reaction-diffusion equation. For small values of the parameter ε, a parabolic boundary layer arises in a neighbourhood of the lateral part of the boundary. In this problem, the error of a discrete solution in the maximum norm grows without bound even for fixed values of the parameter ε. In the present paper, the proximity of solutions of the initial-boundary value problem and of its numerical approximations is considered. Using the method of special grids condensing in a neighbourhood of the boundary layer, a special finite difference scheme converging ε-uniformly in the weight maximum norm has been constructed.

The evolution of travelling waves in reaction-diffusion equations with monotone decreasing diffusivity. I. Continuous diffusivity

1995 ◽  
Vol 350 (1694) ◽  
pp. 335-360 ◽  
Keyword(s):  
Boundary Value Problem ◽  
Boundary Value ◽  
Propagation Speed ◽  
Reaction Diffusion ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Travelling Wave ◽  
Reaction Diffusion Equations ◽  
Classical Solutions ◽  
Initial Boundary Value

We examine the effects of a concentration dependent diffusivity on a reaction-diffusion process which has applications in chemical kinetics. The diffusivity is taken as a continuous monotone, a decreasing function of concentration that has compact support, of the form that arises in polymerization processes. We consider piecewise-classical solutions to an initial-boundary value problem. The existence of a family of permanent form travelling wave solutions is established, and the development of the solution of the initial-boundary value problem to the travelling wave of minimum propagation speed is considered. It is shown that an interface will always form in finite time, with its initial propagation speed being unbounded. The interface represents the surface of the expanding polymer matrix.

scholarly journals Analytic Approximation of Solutions of Parabolic Partial Differential Equations with Variable Coefficients

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Vladislav V. Kravchenko ◽  
Josafath A. Otero ◽  
Sergii M. Torba
Keyword(s):  
Boundary Conditions ◽  
Reaction Diffusion ◽  
Initial Boundary ◽  
Cauchy Data ◽  
Variable Coefficients ◽  
Dirichlet Boundary Conditions ◽  
Reaction Diffusion Equation ◽  
Analytic Approximation ◽  
Transmutation Operator ◽  
Initial Boundary Value

A complete family of solutions for the one-dimensional reaction-diffusion equation, uxx(x,t)-q(x)u(x,t)=ut(x,t), with a coefficient q depending on x is constructed. The solutions represent the images of the heat polynomials under the action of a transmutation operator. Their use allows one to obtain an explicit solution of the noncharacteristic Cauchy problem with sufficiently regular Cauchy data as well as to solve numerically initial boundary value problems. In the paper, the Dirichlet boundary conditions are considered; however, the proposed method can be easily extended onto other standard boundary conditions. The proposed numerical method is shown to reveal good accuracy.

The effects of variable diffusivity on the development of travelling waves in a class of reaction-diffusion equations

1994 ◽  
Vol 348 (1687) ◽  
pp. 229-260 ◽  
Keyword(s):  
Boundary Value Problem ◽  
Travelling Waves ◽  
Boundary Value ◽  
Reaction Diffusion ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Travelling Wave ◽  
Reaction Diffusion Equations ◽  
Classical Solutions ◽  
Initial Boundary Value

In this paper we examine the effects of concentration dependent diffusivity on a reaction-diffusion process which has applications in chemical kinetics and ecology. We consider piecewise classical solutions to an initial boundary-value problem. The existence of a family of permanent form travelling wave solutions is established and the development of the solution of the initial boundary-value problem to the travelling wave of minimum propagation speed is considered. For certain types of initial data, ‘waiting time’ phenomena are encountered.

scholarly journals The stability of solutions in an initial-boundary reaction-diffusion system

1992 ◽  
Vol 46 (3) ◽  
pp. 441-448
Author(s):  
E. Tuma ◽  
C.M. Blázquez
Keyword(s):  
Boundary Value Problem ◽  
Reaction Diffusion ◽  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Stability Of Solutions ◽  
Boundary Values ◽  
Smooth Functions ◽  
The Stability ◽  
Initial Boundary Value ◽  
Boundary Reaction

We study the asymptotic behaviour as t → ∞ of solutions of the initial-boundary value problem vt = G(u, v), ut = uxx + F(u, v), and t > 0, x ∈ ℝ or x ∈ ℝ+ for a wide class of initial and boundary values, where F and G are smooth functions so that the system has three rest points.

Sign in / Sign up

Export Citation Format

Share Document