Elsevier

Chaos, Solitons & Fractals

Volume 127, October 2019, Pages 257-271
Chaos, Solitons & Fractals

Analysis of a new partial integro-differential equation with mixed fractional operators

https://doi.org/10.1016/j.chaos.2019.06.005Get rights and content

Abstract

We have introduced a new partial integro-differential equation with mixed fractional operators. The differential operator can be taken as Caputo while the integral is consider to be Caputo–Fabrizio or the Atangana–Baleanu integral. We presented the well poseness of the new class of partial differential equation. We presented the conditions which the existence and uniqueness are obtained. We presented the derivation of exact solution under some conditions. We suggested a numerical scheme that will be used to solve such mathematical equations. We presented some illustratives examples.

Introduction

Integro-differential equations while being very important class of mathematical equations have not been intensively studied in the last years. One of the challenges in studying this class of equation is perhaps to obtain a closed-form solution as this can be sometimes very challenging. We shall recall that integro-differential equations can capture many physical occurrences arising in science and engineering for instance, the Kirchhoff second law [1], [2]. The Wilson-Cowan model, for this model, the activity of interacting and excitatory neurons can be depicted using the system of integro-differential equations.

We can also mention the model of a radiation energy intensity along the ray of a vector IL in the emitting, absorbing and scattering medium γIL can be very accurately described by an integro-differential equation of radiation transfer. We have also the Prandf equation for air circulation in the vicinity of the plane wring [3], [4]. We can mention the heat conduction model that accounts for a finite velocity of heat transport in the medium, including a relaxation time τ [20], [21], [22], [23], [24]. One can quote many more, however, most of these problems are described using classical differential and integral operators which have not being successful in modelling very complex problems. While fractional calculus is a booming subject in the last years, the derivatives based on power law has witness great success in the field of modelling, the field has witness a great revolution [5], [6], [7], [8], [9], [10], [11], [12]. Recently as some already well-established theories were questioned and new differential operators and integrations were suggested [13], [14], [15], [16], [17], [18], [19]. Also in literature, there have been some studies which include recent developments in the field of the fractional calculus as well as its applications, for example, model of spring pendulum in fractional sense [25], [26], [27], [28]. One of the limitations that was extended is perhaps the singularity problem and also the crossover property. Thus due to the revolution and suggestion of the new fractional calculus, one new mathematical equation can be constructed and be used to open new doors of investigation in theory and modelling.

In this paper, we introduce a new fractional integro-differential equation with mixed fractional operators for example we will consider the following equation0ABCDtαu(x,t)=f(x,u,t)+0CFJtαK(x,u,t)+g(x,t)where 0ABCDtα is the Atangana–Baleanu fractional derivative and 0CFJtα is the Caputo–Fabrizio integral or we can take0CFDtαu(x,t)=f(x,u,t)+0ABJtαK(x,u,t)+g(x,t).

This paper is organized as follows. In Section 2, we present some definitions that will be used in this article. In Section 3, we introduce and study a new fractional integro-differential equation with mixed operators and we give numerical scheme for this equation. In Section 3, we handle fractional integro-differential equation with differential and integral operators. In Section 5, we construct numerical scheme for this equation. In Section 6, we present some examples of the suggested equations and present their numerical approximations. Also we give numerical simulation with the considered problem for different values of fractional orders.

Section snippets

Preliminaries

In this section, we give some definitions used in this article.

Definition 1

Let f: R+R and α(n1,n),nN. The left Caputo fractional derivative of order α of the function f is given by the following equality;D0αf(t)=1Γ(nα)0t(tτ)nα1f(n)(τ)dτ,t>0.Dβ f (t) is the right fractional Caputo derivative.

Definition 2

Let f(t) be continuous and differentiable on C1[0,1], then the Caputo–Fabrizio derivative with fractional order 0 < α ≤ 1 is given as follows.  0CFDtαf(t)=M(α)1α0tdf(τ)dτexp(α(tτ)1α)dτ.

Definition 3

Let f(t)W21(0,T), a

Caputo–Atangana–Baleanu volterra equation

In this section, we introduce and study the following fractional integro-differential equation0CDtαu(x,t)=g(x,t)+f(x,t,u)+1αAB(α)K(x,t,u)+αΓ(α)AB(α)0tK(x,τ,u)(tτ)α1dτand0ABCDtαu(x,t)=g(x,t)+f(x,t,u)+1Γ(α)0tK(x,τ,u)(tτ)α1dτ.

We shall start our investigation with Eq. (1). We reformulate Eq. (1) as followu(x,t)u(x,0)=1Γ(α)0tg(x,τ)(tτ)α1dτ+1Γ(α)0tf(x,τ,u)(tτ)α1dτ+1αAB(α)1Γ(α)0tK(x,τ,u)(tτ)α1dτ+αAB(α)1Γ(2α)0tK(x,τ,u)(tτ)2α1dτ.

Theorem 8

If the functions g, f and K are bounded, then the

Caputo–Fabrizio volterra equation

In this section, we introduce the following fractional integro-differential equations0CDtαu(x,t)=g(x,t)+f(x,t,u)+1αM(α)K(x,t,u)+αM(α)0tK(x,τ,u)dτand0CFDtαu(x,t)=g(x,t)+f(x,t,u)+1Γ(α)0tK(x,τ,u)(tτ)α1dτ.

For both cases, we present existence and uniqueness of the exact solution using a very preliminary technique of Banach fixed-point theorem. Additionally, we present for both cases derivation of the numerical technique suitable to solve them. We start with the first case where the derivative

Numerical method

In this section, we present the numerical method that can be used to solve Eq. (75).u(x,t)=u(x,0)+1αM(α)g(x,t)+αM(α)0tg(x,τ)dτ+1αM(α)f(x,t,u(x,t))+αM(α)0tf(x,τ,u(x,τ))dτ+1αM(α)1Γ(α)0tK(x,τ,u(x,τ))(tτ)α1dτ+αM(α)1Γ(α+1)0tK(x,τ,u(x,τ))(tτ)αdτ.

At (xi,tn+1), we haveuin+1=ui0+1αM(α)g(xi,tn+1)+αΔtM(α)j=0ng(xi,tj)+1αM(α)f(xi,tn,uin)+αM(α)j=0nf(xi,tj,uij)+1αM(α)(Δt)αΓ(α+2)j=0n[K(xi,tj,uij){(nj+1)α(nj+2+α)(nj)α(nj+2+2α)}K(xi,tj1,uij1){(nj+1)α+1(nj)α(nj+1+α)}]+αM(α)(Δt)α+1Γ(α+3)

Illustrative examples and simulations

In this section, we present some examples of the suggested equations and present their numerical approximations. We consider the following examples0CDtαu(x,t)=g(x,t)+xu(x,t)+1αM(α)2x2u(x,t)+αM(α)0t2x2u(x,τ)dτand0CFDtαu(x,t)=g(x,t)+xu(x,t)+1Γ(α)0t2x2u(x,τ)(tτ)α1dτ.

We present numerical solution of the first equation using both scheme. Thus for Volterra case, we haveuin+1=ui0+(Δt)αΓ(α+1)j=0ngijδn,jα+(Δt)αΓ(α+2)j=0n[ui+1jui1jΔx{(nj+1)α(nj+2+α)(nj)α(nj+2+2α)}ui+1j1ui1j1Δ

Conclusion

The nature is above the understanding of making because mankind live within it, therefore he is part of it. Nevertheless due to continuous improvement by mankind within the environment he lives, it is required to him to understand, analysis and predict it. We have to confess that up to new mankind has really devoted his attention in modelling real world problems using mathematical equations that are constructed using differential and integral operators. One can find in the literature many

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