Научная статья на тему 'An efficient method for the analytical study of linear and nonlinear time-fractional partial differential equations with variable coefficients'

An efficient method for the analytical study of linear and nonlinear time-fractional partial differential equations with variable coefficients Текст научной статьи по специальности «Математика»

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Ключевые слова
Laplace transform / residual power series method / partial differential equation / Gerasimov–Caputo derivative / преобразование Лапласа / метод остаточных степенных рядов / уравнение в частных производных / производная Герасимова– Капуто

Аннотация научной статьи по математике, автор научной работы — Muhammad Imran Liaqat, Ali Akgül, Evgenii Yu. Prosviryakov

The residual power series method is effective for obtaining approximate analytical solutions to fractional-order differential equations. This method, however, requires the derivative to compute the coefficients of terms in a series solution. Other well-known methods, such as the homotopy perturbation, the Adomian decomposition, and the variational iteration methods, need integration. We are all aware of how difficult it is to calculate the fractional derivative and integration of a function. As a result, the use of the methods mentioned above is somewhat constrained. In this research work, approximate and exact analytical solutions to time-fractional partial differential equations with variable coefficients are obtained using the Laplace residual power series method in the sense of the Gerasimov–Caputo fractional derivative. This method helped us overcome the limitations of the various methods. The Laplace residual power series method performs exceptionally well in computing the coefficients of terms in a series solution by applying the straightforward limit principle at infinity, and it is also more effective than various series solution methods due to the avoidance of Adomian and He polynomials to solve nonlinear problems. The relative, recurrence, and absolute errors of the three problems are investigated in order to evaluate the validity of our method. The results show that the proposed method can be a suitable alternative to the various series solution methods when solving time-fractional partial differential equations.

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Эффективный метод аналитического исследования линейных и нелинейных дробно-временных уравнений в частных производных с переменными коэффициентами

Метод остаточных степенных рядов эффективен для получения приближенных аналитических решений дифференциальных уравнений дробного порядка. Вычисление дробной производной для коэффициентов степенного ряда, аппроксимирующего точное решение дифференциального уравнения, является недостатком этого метода. Другие известные методы приближенного интегрирования, такие как гомотопическое возмущение, разложение Адомиана и методы вариационных итераций, основываются на интегрировании для получения степенного ряда. Известна сложность вычисления дробных производных и интегрирования функций при построении степенного ряда для решения уравнений математической физики дробного порядка, поэтому использование упомянутых выше методов ограничено спецификой решаемой задачи. В настоящей статье получены приближенные и точные аналитические решения уравнений в частных производных переменными коэффициентами при использовании метода рядов остаточных степеней Лапласа в смысле дробной производной Герасимова–Капуто для времени. Этот метод помог преодолеть ограничения упомянутых выше способов интегрирования уравнений дробного порядка. Метод остаточных степенных рядов Лапласа лучше использовать при вычислении коэффициентов членов в решении ряда, применяя принцип прямого предела на бесконечности. Он также более эффективен, чем различные методы решения, если не использовать полиномы Адомиана и He для решения нелинейных задач дробного порядка. В статье исследуются относительные, повторяющиеся и абсолютные ошибки для трех задач математической физики для оценки достоверности предложенного метода. Результаты показывают, что сконструированный метод является альтернативой различным методам для построения решения рядами при решении уравнений в частных производных с дробным временем.

Текст научной работы на тему «An efficient method for the analytical study of linear and nonlinear time-fractional partial differential equations with variable coefficients»

Vestn. Samar. Gos. Tekhn. Univ., Ser. Fiz.-Mat. Nauki

[J. Samara State Tech. Univ., Ser. Phys. Math. Sci.], 2023, vol. 27, no. 2, pp. 214-240 ISSN: 2310-7081 (online), 1991-8615 (print) d https://doi.org/10.14498/vsgtu2009

MSC: 26A33, 44A10, 45J05

An efficient method for the analytical study of linear and nonlinear time-fractional partial differential equations with variable coefficients

M. I. Liaqat1,2, A. Akgül3,4,5, E. Yu. Prosviryakov'

6,7,8,9

Government College University, Lahore, 54600, Pakistan.

National College of Business Administration & Economics, Lahore, 54660, Pakistan.

Lebanese American University, Beirut, 1102 2801, Lebanon.

Siirt University, Siirt, 56100, Turkey.

Near East University, Nicosia, 99138, Turkey.

Ural Federal University, Ekaterinburg, 620137, Russian Federation.

Institute of Engineering Science, RAS (Ural Branch),

Ekaterinburg, 620049, Russian Federation.

Urals State University of Railway Transport,

Ekaterinburg, 620034, Russian Federation.

Udmurt Federal Research Center, RAS (Ural Branch),

Izhevsk, 426067, Russian Federation.

8

9

Abstract

The residual power series method is effective for obtaining approximate analytical solutions to fractional-order differential equations. This method, however, requires the derivative to compute the coefficients of terms in a series solution. Other well-known methods, such as the homotopy perturbation, the Adomian decomposition, and the variational iteration methods, need integration. We are all aware of how difficult it is to calculate the fractional derivative and integration of a function. As a result, the use of the methods mentioned above is somewhat constrained. In this research work, approximate and exact analytical solutions to time-fractional partial differential equations with variable coefficients are obtained using the Laplace residual power series method in the sense of the Gerasimov-Caputo fractional derivative. This method helped us overcome the limitations of the various methods. The Laplace residual power series method performs exceptionally well in computing the coefficients of terms in a series solution by applying the straightforward limit principle at infinity, and it is also more effective than various series solution methods due to the avoidance of Adomian

Differential Equations and Mathematical Physics Research Article

© Authors, 2023

© Samara State Technical University, 2023 (Compilation, Design, and Layout)

3 ©® The content is published under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/) Please cite this article in press as:

Liaqat M. I., A kg ul A., Prosviryakov E. Yu. An efficient method for the analytical study of linear and nonlinear time-fractional partial differential equations with variable coefficients, Vestn. Samar. Gos. Tekhn. Univ., Ser. Fiz.-Mat. Nauki [J. Samara State Tech. Univ., Ser. Phys. Math. Sci.], 2023, vol. 27, no. 2, pp. 214-240. EDN: XAVFLR. DOI: 10.14498/vsgtu2009. Authors' Details:

Muhammad Imran Liaqat © https://orcid.org/0000-0002-5732-9689

PhD Student, Abdus Salam School of Mathematical Sciences1; Lecturer, Dept. of Mathematics2; e-mail: [email protected]

and He polynomials to solve nonlinear problems. The relative, recurrence, and absolute errors of the three problems are investigated in order to evaluate the validity of our method. The results show that the proposed method can be a suitable alternative to the various series solution methods when solving time-fractional partial differential equations.

Keywords: Laplace transform, residual power series method, partial differential equation, Gerasimov-Caputo derivative.

Received: 18th March, 2023 / Revised: 12th June, 2023 / Accepted: 19th June, 2023 / First online: 27th June, 2023

List of abbreviations

RPSM residual power series method

HPM homotopy perturbation method

ADM Adomian decomposition method

VIM variational iteration method

TFPDEs time-fractional partial differential equations

LRPSM Laplace residual power series method

GCFD Gerasimov-Caputo fractional derivative

DEs differential equations

FODEs fractional order differential equations

Rel-E relative error

Abs-E absolute error

Rec-E recurrence error

LRF Laplace residual functions

Ali Akgülfa ©https://orcid.org/0000-0001-9832-1424

PhD in Math, Full Professor; Dept. of Computer Science and Mathematics3; Dept. of Mathematics, Art and Science Faculty4; Dept. of Mathematics, Mathematics Research Center5; e-mail: [email protected]

Evgenii Yu. Prosviryakov © https://orcid.org/0000-0002-2349-7801

Dr. Phys. & Math. Sci.; Dept. of Information Technologies and Control Systems6; Sect. of Nonlinear Vortex Hydrodynamics7; Dept. of Natural Sciences8; Lab. of Physical and Chemical Mechanics9; e-mail: [email protected]

1. Introduction. Fractional calculus deals with fractional order derivatives and integrations. Fractional calculus was founded by two mathematicians, Leibniz and l'Hôpital, and its official birthday is September 30, 1695. The widespread usage of fractional calculus in fields including image processing, physics, engineering, biology, biochemistry, entropy theory, and fluid mechanics has attracted a lot of researchers in recent years [1-5]. There are numerous definitions for fractional order derivatives; however, not all of them are regularly applied. The Grunwald-Letnikov, Hadamard derivative, Riemann-Liouville, conformable, and Gerasimov-Caputo fractional derivative (GCFD) are the most well known fractional order derivatives [6-9].

The GCFD of order p > 0 is given by [10]:

1 fw dr

(w - q)v-ri-l-j— #(q)dq, r - 1 <[3<r,

D^ = I r,(:- p)J* dq

I — X(w), P = r e N.

The following are the important properties of GCFD:

(i) D&Z = 0, £ e R,

(ii) dO, ^ = + + ) , r - 1 <p < r, £>r - 1, r e N, £ e R,

(iii) DO, (Cl ^l(w) + ^2(w)) = ZiDO, (u) + t2DZ *2(u).

In some cases, fractional order derivatives are preferable to integer-order derivatives for modeling because they can simulate and examine complex structures with complicated nonlinear processes and higher-order behaviors. There are two main causes of this. First, rather than being limited to an integer order, we can choose any order for the fractional order derivatives. Furthermore, when the mechanism has long-term memory, fractional order derivatives are advantageously based on both past and present situations.

In the disciplines of science and engineering, there are natural and physical phenomena that, when described by mathematical relations, turn into differential equations (DEs). Examples of phenomena that are characterized by DEs include equations of motion, simple harmonic motion, beam deflection, and more. The fractional order differential equations (FODEs) have developed a convenient means of expressing naturally occurring phenomena in artificial intelligence, engineering, physics, earth sciences, bioinformatics, finance systems, and biological systems. Consequently, the study of the approximate or exact solution enables us to recognize the mechanism of these FODEs, and their actual physical intention can be perceived from the graphical depiction of the solution. Applications often come with FODEs that are so complex that exact solutions are frequently impractical. For solving FODEs in the initial circumstances given, methods that give approximate solutions present a potent alternative tool. In recent times, numerous approximate methods for solving FODEs have been presented [11-19].

The residula power series method (RPSM) is a very powerful approach in terms of the construction of power series solutions for FODEs. Many FODEs have been successfully solved by RPSM. Y. Zhang et al. [20] used RPSM to develop series solutions of the time-fractional Schrodinger equation. A. El-Ajou et al. [21] studied the KdV-Burgers equation to find approximate solutions. R. Saadeh et al. [22] discussed the fractional Newell-Whitehead-Segal equation by the RPSM.

Approximate analytical solutions of FODEs can be solved effectively using the RPSM. However, to determine the coefficients of the series solution, the (n — derivative of the residual function is required. As we all know, it is difficult to compute the fractional order derivatives of a function. This limits the application of the classic RPSM to a certain extent. To overcome this drawback, T. Eriqat et al. [23] introduced a new approach, known as the Laplace residual power series method (LRPSM), which is the coupling of the Laplace transforms and the RPSM for approximate series solutions of linear and nonlinear FODEs. The limit idea is used to establish the series coefficients in the LRPSM. The set of guidelines for this novel approach is based on converting the specified equation into the Laplace transforms space, identifying an expansion solution to the transformed equation, and then obtaining the original equation's solution by using the inverse Laplace transform.

Finding solutions to FODEs with variable coefficients is also an interesting area for researchers. E. Hesameddini and A. Rahimi [24] used the variational iterative approach to solve FODEs with variable coefficients. Y. Keskin et al. [25] used the generalized Taylor collection technique to find solutions for higher-order linear FODEs with variable coefficients. S. Sarwar et al. [26] found approximate solutions to time-fractional wavelike models with variable coefficients using the definition of the GCFD and with the help of optimal homotopy asymptotic method. With the operational matrix technique, D. Rostamy and K. Karimi [27] established approximate solutions of fractional-order wave and heat equations with variable coefficients. H. Bulut et al. [28] used the Sumudu transform method to obtain approximate solutions for partial differential equations with variable coefficients. M. Nadeem et al. [29] established numerical solutions for the fourth-order parabolic partial differential equation with variable coefficients using the modified Laplace variational iteration method. M. Dehghan and J. Manafian [30] used the homotopy perturbation technique to find a solution for a fourth-order parabolic problem with variable coefficients. T.M. Elzaki and S.M. Ezaki [31] established solutions for ordinary DEs with variable coefficients using the Elzaki transform method. Each of these strategies has particular limitations and drawbacks. These methods require a lot of work and longer running times.

In this research, the LRPSM was used to solve time-fractional partial differential equations (TFPDEs) with variable coefficients in the sense of GCFD. This method combines the Laplace transforms with the RPSM, which is based on a revamped version of Taylor's series and yields a convergent series as a solution. By employing the simple limit principle at infinity, the LRPSM excels at calculating the coefficients of terms in a series solution, but other well-known methods such as the variational iteration method (VIM), Adomian decomposition method (ADM), and homotopy perturbation method (HPM) need integration, while the RPSM needs the derivative, both of which are challenging in fractional contexts. LRPSM is also more effective than various series solution methods due to its small processing size and avoidance of Adomian and He polynomials to solve nonlinear problems. Moreover, this method does not require any assumptions about physical parameters, no matter how big or small, for the problem. Therefore, it can be used to handle both mildly and severely nonlinear problems and to circumvent some of the issues that perturbation techniques previously had. To evaluate the efficiency and consistency of the suggested strategy, the relative error (Rel-E),

recurrence error (Rec-E), and absolute error (Abs-E) of the three problems are examined. The findings demonstrate that when solving FODEs, the LRPSM can be a viable substitute for the RPSM, VIM, ADM, and HPM.

To emphasize the essential ideas of our suggested method, such as its dependability, capability, and application, we selected the most prevalent forms of TFPDEs with variable coefficients. J. Fourier proposed the heat equation in 1822, which defines how a certain amount of heat diffuses over a region. Consider the TFPDE with variable coefficients shown below [27]:

DfX(6,u) + 3(0)tf(X) - E(6, X)=0, (1)

subject to the initial condition:

Df X(6, 0)=$v,

where q = 0,1,2,3 ...,k - 1; 6 = (61,62,... ,6e) e Re; P e (^ ], k e N, and tf(X) = tf(X, DO, X, D2J X,..., D^-1^ X, D^1 X, Dfe\2 X, ..., D^X, ..., D^1 X, D£ep22 X,...,Dhe X), with h - 1 <lhu < h, h = 1, 2,...,p; u = 1, 2,...,e.

The GCFD of w of order -qfi and 6U of order lhu are represented by Dljf and Dfdhu, respectively. These kinds of DEs give accurate representations of a wide range of physical events in the fields of fluid dynamics, elastic mechanics, and electrodynamics [26-33].

This study is structured as follows. First, in Section 2, we present significant definitions and findings from FC theory. The LRPSM algorithms for solving TFPDEs with variable coefficients are discussed in Section 3. In Section 4, some linear and nonlinear TFPDE problems are solved to demonstrate the accuracy and reliability of LRPSM. The numerical and graphic results obtained using LRPSM are evaluated in Section 5. Finally, we conclude the paper in Section 6.

2. Preliminaries. In this section, basic definitions, Laplace transform characteristics, and LRPSM-related theorems that help establish approximate series solutions are included.

Definition 1 [34]. The Laplace transforms of X(6,w) is defined as follows:

£[X(0,w)l = Q(6,u) = / X(6,u)e—MV dw,

J 0

and the inverse Laplace transforms is defined by

C—i[Q(6,u)] = X(0,u) = e™Q(d,v)dv, b = Re(u) > bo,

Jb—i<x

where 6 = (d1,d2,... ,de) e Me and e e N and b0 lies in the right half plane of the absolute convergence of the Laplace integral.

Lemma 1 [23]. Consider that Xi(0, w) and X2(6,u) satisfy the axioms of the existence of Laplace transforms. Suppose that £[Xi(0, w)j = Q1(6,u),, £[X2(0, w)j = Q2(6,u) and the constants £1, (2. When this occurs, the following criteria are met [23,24]:

(i) £[CiXi(6, u) + (2X2(0, w)j = (iQi(6, u) + №2(6, v);

(ii) C-1[ Cifii(9,v) + 9,v)] =CiNi(0,w) + (2^2(9,w);

(iii) £o(0) = lim v0(9, v) = K(d, 0);

(iv) C\dI N( 9, w)] = v3 0( 9, v) - 0 ), r- 1 <p < r, re N;

j=o V

r-1

(v) C[Dlf N(0,w)] = vr3fi(0, v) - ^ v3(r-j)-1Dj*N(0, 0), 0 < 1.

j=o

Definition 2 [35]. The multiple fractional power series is defined as follows:

œ

^ £r( 9)(w - wo)r3 = £o(w - wo)0 + № - wo)3 + 6(w - wo)23 + ■ ■ ■ ,

r=o

where 9 = ( 91,92,..., 9e) e Re and e e N, w represent a variable and (9) represent the coefficients of the multiple fractional power series.

We present a new type of multiple fractional power series in the sense of Laplace transform space in the following lemma, which is the main pillar for the LRPSM.

Lemma 2 [23]. Assume that the multiple fractional power series demonstration is in Laplace transforms space for the function 9,w)\ = 0(9, v) as shown follows:

^v) = £ Vr^, v> 0,

r=o

where, 9 = ( 9X, 92,..., 9e) e Re, e e N.

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Theorem 1 [23]. The coefficients of the multiple fractional power series can be determined as follows:

£r(9)=Dl3N(9,0),

where DrJ3 = D3 ■ D3 ■ ■ ■ D3 (r times).

The following theorem establishes the prerequisite for the convergence of the new form of multiple fractional power series.

Theorem 2 [23]. Let 9, w)] = 0(9, v) can be denoted as the new form of multiple fractional power series given in

Lemma . If \vC\D{J+1)3N(9, w)] \ ^ V on 0 < v ^y with 0 < ft ^ 1, then the remainder Rj (9, v) of the multiple fractional power series satisfies the following inequality :

\Rj,v)\ < Jmt, 0 <v ^

3. LRPSM for Solving TFPDEs with Variable Coefficients. In this section, the set of steps for employing the suggested method to acquire approximative analytical solutions to TFPDEs is addressed. First of all, we apply the Laplace transforms to the TFPDEs with variable coefficients and get an algebraic expression as a result. Then, we take into account the multiple fractional power series as the new space solution for the resulting expression obtained in the first step, which is the fundamental idea behind the LRPSM. The way in which the

coefficients of this series are obtained by employing the limit idea is the primary difference between the LRPSM and the RPSM. The resulting implications are then translated into actual space using the inverse Laplace transforms. The rules for using the LRPSM to locate solutions are listed below.

The LRPSM Algorithm for Linear and Nonlinear TFPDEs. We describe the LRPSM's set of guidelines for solving Eq. (1).

Step 1. Reformatted Eq. (1):

D£3K(0,w) + - H(d, N)=0. (2)

Step 2. Utilize C on both sides of Eq. (2):

C D3N(d, w) + - E(d, N)] = 0. (3)

Using the Lemma 1(v) and the initial condition, we get the following from Eq. (3):

w ,v) = I-:D + ^v!, (4)

v ' ' j/j3+1 vj3 vj3 ' v '

vj3+1 vj3 vj3

=o

where £[H(d,N)] = A(d, v), £[tf(N)] = B(v).

Step 3. Assume that the multiple fractional power series solution of Eq. (4) in Laplace transforms space is below:

0(*, v) = £ H+1, v> 0.

=o

Step 4. As a result of applying the Lemma 1(iii) and Theorem 1 we obtained the following results:

£o(0) = lim v0(d,v) = X(e, 0),

6( e) = D33 a( e, 0), 6W = D23 X(0, 0), tv (®) = Df a( e, 0).

Step 5. Assume that the jth truncated multiple fractional power series solution of Eq. (4) is below:

0j(d, v) = £

Cr (e) vr3+1:

v > 0,

=o

0 (0 v) &(*) + + + Cv(0) + v ^(0)

°j( V,v) = + 73+T + ■ ■ ■ + 7V3+ +

v v3+1 vr3+1'

r=v+1

Step 6. The Laplace residual functions (LRF) and jth truncated LRF for the Eq. (4) are defined as follows:

C Res, ,„=n(M) - £ ^ + ~ -4M

3=0

and

rr, tn ^ r^./. N ^i D3" X(9,0) -(9)B(u) A(9,u) C ReSj (9, u) = n, (9, u) - £ —^ + -±±¿-1 - . (5)

3=0

Step 7. By inserting the jth truncated multiple fractional power series into the Eq. (5) we get the following:

CRes,) = (+ M+... + ^ + £ ^)

r=r+i

Dj X(d, 0) + -(d)B(v) A(d,v)

uj/3+i + uj/3 uj/3 . (6)

3=0

Step 8. Multiplying the resulting expression CReSj(9,v) by on both sides of Eq. (6):

V V £P+i vrP+i vrl3+i

r=r+i

DjX(9, 0) + -(9)B(y) A(9, v) \ (7

U3i3+i + i/jfi i/jfi ). (7

3=0

Step 9. Applying lim on both sides of Eq. (7):

lim v^C Res3 {9, u) = lim ^ (^ + !# + ••• + -^g) +

+ ^ V D"X(0) + -(O)B(iy) A(9, v) \

r=r+i j=0

Step 10. Solve the following expression for (j(9):

lim (vjfi+iC ReSj(9, v)) =0,

where j = r] + 1,7] + 2,....

Step 11. To obtain the jth step approximate solution of Eq. (4), substitute the obtained values of (j(9) into a jth truncated series of Q(9, v).

Step 12. Apply the C 1 on 0j( d,v) to attain the jth approximate solution

Nj-( M).

4. Applications to Linear and Nonlinear TFPDEs with Variable Coefficients. In this section, to show the applicability and reliability of the novel algorithm, three linear and nonlinear TFPDEs are solved.

Problem 1. In our first illustration, we take the nonlinear TFPDE provided below [33]:

Df X(61, w) = K2(01, w)i (01, w)*o,o, (01, w)*o,0,0, (01, w)) +

+ (N(01, w))2—2 (Xeiei (01, w))3 - 18tt5(01, w) + N(01, w), (8)

where 0 < ft ^ 1, u ^ 0, 0i G R, and with the following initial conditions:

N(01,0)=ee 1, D3/N(0, 0)=ee 1.

By applying C to Eq. (8),

r d2

C[DfX(di, u)] = C |_K2(0i, u)^ (^i(^i, u)*0i0i(^i, wi (01, u)) +

+ (01, w))2-—2(^i (^1,w))3 - 18tt5(01 ,w) + 1,w) . (9

By following the steps that are established in Section 3, we get the following result from Eq. (9):

e0i e0i ^(0 i, V) = e- + +

+ — C + v 23 C

2

(C-1[Q(01, v)])2—C-1[Q(01, v)] x

—2 —3 x c-1[0(e, v)]^c-1[Q(01, v)])

de 12 1 v ' Jc-e13 1 v ^ nj

+

+ ^ c

+ v23 C

, — \2—2 / —2 \3

— 5

- 18(C-1[0( 01, v)])5 + ^0(01, v). (10)

./2/3

Consider the series solutions of Eq. (10), which have the following form:

^- ")=z , "> 0.

r=0

The jth truncated expansion is as

W(* 1. *) = t , ^ 0-

r=0

As a result of applying the Lemma 1(iii) and Theorem 1, we obtained the following results:

lim (un(Oi,v)) = X(9i, 0)= Oi)=ed1, 6(Oi) = D?X(61, 0) = e'1. So, Eq. (10) becomes as follows:

^ (° i, ^ = + +E

The following is the LRF for Eq. (10):

e01 e01 CRes(di, v) = n(0i, v)---

' (Oi)

v V/3+1 •

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r=2

(11)

- _!_ c

V

{C-i[W( Qi,v )]) d2

v

2d2 ( d

de Adm c-1[n(e i-")]x

d

-, c-1[W( o i, v)]—3 c-i[Q( o i,v )] dOi2 1 v h nd0i3

__r

V2i3 C

, d \ 2 d2 / d2 \ 3

f—r-1[Q(ei,u)]) -^c^Mei.v)]) -

d

- 181 C

1

[W( e i, !/)])

- ^ W l* )■

The following is the jth truncated LRF for Eq. (10):

f>i

CReSj(0i,v) = W(Oi, v)---

e

f>i

c

{C-1[W(di, u)])

V

d2 f d

2

r-i

d i2 d i

C-i[Wj(Oi, v)] x

d2 d3

x — C-i[W(01, V)]—3C-i[W(01, u)] d i3

d 0i2

c

'i dU i

. d \ 2 d2 / r)2 \3

1

- 1^C-i[nj (Oi, u)]j J- ^ W (Oi, V). (12)

In Eq. (11) and Eq. (12), use j = 1, 7 to find the undetermined coefficients (di, 0 2), and then solve the following:

lim (vjfi+iCResj(Oi, u)) =0.

x

5

1

The following outcomes obtained:

6( tfi)=eei, 6( ^i)=e01, & 0i)=ee i,

&( 0i)=e01, &( 0i)=e*1, &( 0i)=e*1.

In this way, we obtained the following 7th step approximate solution of Eq. (10) in Laplace transforms space:

°7( °1,v)=e 1 ( ^ + vзтт + vw + J+ +

i i i i A r .

+ 2,43+1 + v5/+i + v6/+i + ^7/3+T J . (13)

By applying C-1 to Eq. (13), we obtain the approximate 7th step solution in the original space, which has the following form:

, . ,3 . .23 . .33

>.v //1 \ 01 w w w

^ 1,w) = e'\ 1++ WTÎ] + wn + fMm +

w43 w53 w63 w73

+ , H1 + , H1 + , H1 +

T[4ft + 1] T[5f3 + 1] T[6f3 + 1] T[7f3 + 1] When ft = 1.0, the 7th step approximate solution is

.

//1 X 01 ^ w w2 w3 w4 w5 w6 w7 \ „X "7(01 ,w) = ee\1 + r2ï + rî3l + rî4l + rî5l + fï61 + fï7i + fï8l). (14)

The first eight terms of the series of the exact solution to d,w) = ed 1 +l are represented by Eq. (14).

Problem 2. In our second illustration, we take the linear TFPDE provided below [32]:

Dl3X(01,02,03, w) = 2^0101 (01, 02,03, w) + 2^0202 (P1,02,03, w) +

+ 2^0,0,(0i, 02, 03, u) + 02 + 022 + 02, (15) where 0 < ft ^ 1, (0i, 02, 03, u) G (R+)4, and with the following initial conditions: N(9i, 02,03, 0) = 0, D3N(6i, 02,03, 0) = 02 + 02 - 02. By applying C to Eq. (15),

C[D33N(01, 02, 03, u)] = C [ 102^0101 (0i, 02, 03, u) + 102^0202 (0i, 02, 03, u) +

+ 103^3*3(0i, 02, 03, u) + 02 + 02 + 02], (16)

By following the steps that are established in Section 3, we get the following result from Eq. (16):

1 02

di, 62, 03, v) = ^(02 + 02 - #2) + ^De^Q(01,02,03, v) +

2 2

+ (92 +022 + d2). (17)

Consider the series solutions of Eq. (17), which have the following form:

mei,02,03,V) = £^¡^, ,> 0.

r=0

The th truncated series is as

W ( 01, 02, fc, v) = t6 ( °3) ,V> 0. (18)

r=0

As a result of applying the Lemma 1 (iii) and Theorem1, we obtained the following results:

lim (u n(01, 02, 03, v)) = &( 0i,e2, 03) = X( 0i,02, 03, 0) = 0,

6( ft1, 02, 03) = D?X(002, 03, 0) = 02 + 02 - 02.

So, Eq. (18) becomes as follows:

n ( ft ft ft iA (°2 + ft2 - ft3) , ^ &(Pi, ft2, O3) 1 0 (1Q)

n3(fti, ft2, ft3, v) = -TJp+i-+ ^--, v> (1Q)

The following is the LRF for Eq. (17):

V

r=2

L Res(01, 02,03, v) = Q(01, 02,03, v) - (02 + 0% - 0?,) -2 2 ¡De1e1 0i, 02, 0з, v) - 0 2p,De2e2 02, 0з, v) -

2 v2?-»1»1'^ 2 vW

2 1

Dd303 01,02, 03, v)--2Ô+T ( + G"2 + &2).

2 v2!3+1

The following is the jth truncated LRF for Eq. (17):

1 "-2 , Q2 Û2\

CRes,(0i, 02, 03, v) = W(01, O2,03, v) - (02 + 02 - 0$) -2 2 - 2v2PDe1('2 W ( ®l, ®2, ®з, u) - 2y2pD0202 (01, ®2, 03,V) -

2 1 ^De^Qj(°i, °2, °3, v) - -3+1 (°2 + ^ + 03). (20)

In Eq. (19) and Eq. (20), use j = 1, 7 to find the undetermined coefficients £j (d1,0 2), and then solve the following:

lim (vj3+1CRes7(6U 62, 63, v» =0.

The following outcomes obtained:

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s,2(^ 03) = 02 + $2 + ù(6,l, ^ ^ = o\ + q2 - 6>2,

¿¡4(6,2, ^ = + #2 + ^5($1-, 6,2, ^ = #2 + #2 - ^3,

6 ( , 2 , 3 ) = 2 + 22 + 32 , 7 ( , 2 , 3 ) = 2 + 22 - 32 .

In this way, we obtained the following 7th step approximate solution of Eq. (17) in Laplace transforms space:

om o o v) d2 + - + d2 + + + d2 + ^2 - + °7(01, O3,v) = —v3+1— + —vw— + —v33+1— +

2 2 2 2 2 2 2 2 2 2 2 2 + frj + "2 + "2 + ^ + "2 - "2 + ^ + "2 + "2 + ^ + "2 - "2 (21)

+ v4 3+1 + v53+1 + v63+1 + v 73+1 . ( )

By applying C-1 to Eq. (21), we obtain the approximate 7th step solution in the original space, which has the following form:

&1,02,0 3,w) =

= ( f> 2 w3 w33 w53 w73 ^

= ( f2 + 02 + 1] + r[3^ + 1] + ^ + 1] + r[7^ + +

^ f w23 w43 w63 ^ + ( ^ + ^ + O3 ^^ + 1] +r[4^ + 1] +r[6^ + 1]J.

When fi = 1.0, the 7th step approximate solution is

3 5 7

^ 1, ™ = 2 + ^ - )( ri + H4j + m + ) +

+ («? + * + + m + (22)

,r[3] + r[5] + r[7] The first seven terms of the series of the exact solution to

N(d 1,92, 03,u) = (02 + 02 - 0s) sinhU + (^2 + #2 + ^2)(coshU - 1) are represented by Eq. (22).

Problem 3. In our third illustration, we take the nonlinear TFPDE provided below [33]:

Dl3a(9 1, d2,.) = d—^(a0101 (e 1,02,.)ae202(o 1,02,.)) -

- d—df2(°1,02,u)a«2(°1,°2,.)) - a(61,.), (23)

where 0 < ft ^ 1, (d1, d2,u) G (R+)3, and with the following initial conditions:

a(91,92,0) =e0102, D33a(91,92,0) = e0102.

By applying C to Eq. (23),

c[Dl3a(01,02,.) = c[d^(a0101 (01,02,w)a0202(61,02,.)) -

—2 1

(0102«^ (01, 02,w)a02 (01, 02,.)) -a(01, 02, .) . (24)

091d9-

By following the steps that are established in Section 3, we get the following result from Eq. (24):

ei?102 ei?102 Wu 02, V) = — + +

0 2

+ ^ C + v 23 C

JL C v23 C

Vd91—02

(D0101 C-1[0( 01,02, v)]D,202 C-1[0( 01,02, v)])

d

2

( 0102D.1 C-1[0(01,02, v)]D02C-1[0(01,02, v)])

1

- Q(01,02,1/). (25) Consider the series solutions of Eq. (25), which have the following form:

=o

The th truncated expansion is as

1. «2, v)=¿^S^ ■ v> 0.

=o

As a result of applying the Lemma 1(iii) and Theorem 1, we obtained the following results:

lim (uQ(91,02,v)) = N(0i,02,0) = &(0i) = e0102,6(01) = D/N(0i,02,0) = e0102.

V

So, Eq. (26) becomes

v V/3+1

r=2

v > 0.

(26)

The following is the LRF for Eq. (25):

CRes(Oi, 02,u) = Q(01,02, v) -

e0102 e@1@2

„¡3+1

1 ~2,8

c

d2

+ V2P C

VdO id Ô2 d2 .d did 02

{D0101 C-1[W(0i, 02, v)]Dd2e2C-1[W(0i, 02, v)]) ( 0i02DdlC-1\W(0i, 02, v)\Dd2C-1\W(01, 02, v)])

+ +

+ W3 »( ^ e2,V )-

The following is the jth truncated LRF for Eq. (25):

CResj(0i, 02, v) = »j(di, 02, v) -

e0102 e0102

__r

v2P

+ — C + V2H C

d2

d 1 d 2 d2

(D0101 C-1[Qj(0i, 02, v)]Dd2d2C-1[W(0i, 02, v)]) d0ld02 ^Do, C-1[W ( Oi, 02,v )]Do2 C-1[W (01, 02, u)])

+ +

+ W(01, 02, u). (27)

In Eq. (26) and Eq. (27), use j = 1, 7 to find the undetermined coefficients -j (01,0 2), and then solve the following:

lim (ujfi+1CReSj(Oi, 02, v)) = 0. The following outcomes obtained:

Î2(0i, 02) = -e0102, UQi, O2) = -e0102, U(01,02) =e0102,

-5(0i, 02) =e0102, -6(0i, 62) = -e0102, -7(0i, 02) = -e0102.

In this way, we obtained the following 7th step approximate solution of Eq. (25) in Laplace transforms space:

W7( eu 02,u )=e0102( ± + J+i

1

1

y 2/3+1 y 3/3+1

11

+ TâTT +

+

1

y4/3+1 1 y5/3+1 y6/3+1

u

M

7/3+1 ■

(28)

By applying C 1 to Eq. (28), we obtain the approximate 7th step solution in the original space, which has the following form:

v

«7(01,02,u)=ee 102 ( 1 +

U

2 3

U

3 3

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+

U

4 3

T[f3 + 1] T[2f3 + 1] r[3P + 1] T[4P + 1]

+

+

U

5 3

U

6 3

U

7 3

r[5P + 1] r[6P + 1] r[7P + 1],

When p = 1.0, the 7th step approximate solution is

«7(01,02,U)=ee 102( 1 +

U U

U3 U4 U5 U6

+ ^r +

U7

r[2] r[3] r[4] r[5] r[6] r[7] r[8]

J. (29)

The first eight terms of the series of the exact solution to ee 102 (cos u + sin u) are represented by Eq. (29).

5. Numerical Simulation and Discussion. In this section, the results of the approximate and exact solutions to the problems are examined graphically and numerically. Error functions can be used to evaluate the accuracy of the approximate analytical approach, so it is necessary to specify the errors in the approximate solutions provided by the LRPSM. We used the Abs-E, Rel-E, and Rec-E functions to demonstrate the accuracy and efficiency of LRPSM.

Fig. 1 depicts the 2D graphs of the comparative study of the exact and approximate solutions obtained by the proposed method in Problems 1-3. These figures show the 2D plots of the exact and 7th step approximate solutions attained by LRPSM for Problems 1-3, when p = 0.6, 0.7, 0.8, 0.9, and 1.0 in the range

0=0.6 ■ 0=0.9

0=0.7 ■ 0=1.0

0=0.6 ■ 0=0.9

0=0.7 ■

0=1.0

c

1.0 w

/3=0.8 Exact

1.0 u

0=0.8 Exact

1.0 w

3=0.6 ■ 0=0.9

0=0.7 ■ 0=1.0 b

0=0.8 Exact

Figure 1. The approximate and exact results of K(0i,w) (a), K(0i,02,03,w) (b), and K(01,02,w) (c) for various amounts of ft in the range u € [0,1.0], when 01 = 0.5 (b), 0i = 02 = 03 = 0.5 (b), and 0i = 02 = 0.5 (c)

a

u E [0,1.0]. These graphs indicate that when fî ^ 1.0 is applied, the approximative solution converges to the exact solution. The exact and approximation solutions overlap at fi = 1.0, demonstrating the accuracy and reliability of the proposed method.

Fig. 2 shows the Abs-E of the proposed method's 7th step approximate and exact solutions to Problems 1-3 in the range u E [0,0.5] for ft = 1.0.

Fig. 3 depicts a comparison of the Rel-E of the exact and 7th step approximate solutions to problems 1 - 3 with ft = 1.0 in the range u E [0,1.0]. The graphical analysis of the approximate and exact findings in the form of Abs-E and Rel-E demonstrates the reliability and precision of LRPSM.

Fig. 4 depicts the comparison study using the 3D plots in terms of the Abs-E of the approximate finding from the seven iterations and the exact result found using the suggested method to Problems 1-3, respectively, at ft = 1.0 in the ranges u E [0,0.5] and d E [0, 0.5].

Fig. 5 depicts the comparison study using the 3D curve in terms of the Rel-E of the approximate finding from the seven iterations and the exact result found using the suggested method to Problems 1-3, respectively, at fi = 1.0 in the range u E [0,0.5] and 9 E [0, 0.5].

The study has revealed that the 7th step approximate solutions of the proposed method are very similar to the exact solution. The reliability and accuracy of LRPSM is demonstrated by graphical analysis of approximate and exact results in the form of Abs-E and Rel-E.

Tables 1-3 show Abs-E and Rel-E in the range u E [0,1.0] between the approximate solution obtained from the seven iterations and the exact solution obtained by LRPSM at ft = 1.0 for appropriately chosen values. The amplitudes of Abs-E and Rel-E are shown in Table 1 which range from 2.29781 • 10-11 to 3.04568 • 10-3 and from 2.07914 • 10-11 to 4.55539 • 10-4, respectively, for Problem 1. The inter-

IN — N7|

7 10"8

6 10"8

5 10"8

4 10-8

3 10"8

2 10"8

1 10-8

o.i

0.2 0.3 0.4 0.5 W

a

|N-N'| 1•10"8

8■10-9

6■10-"

4•10~9

2■10"9 ;

Figure 2. The 2D curves of the Abs-E graph of K(01,u) (a), $(61,62,63,^) (b), and $(61 ,62,lS) (c) for the approximate finding obtained through seven iterations and the exact result in the range u € [0,0.5], when 61 = 0.25 (a), 61 = 62 = O3 = 0.25 (b), and O1 = O2 = 0.25 (c)

6■10~8 : 5■10"8 4•10-® 3■10-" 2■10"8 1•10"8

0.1

0.1

0.2 0.3 0.4 0.5 u b

0.2 0.3 0.4 0.5 w

c

IN - N7| N|

2.5 10"8

2 10"8 1

1

1.5 10"s /

/

1 10"8 /

/

5 10"9 /

T-

0.1 0.2 0.3 0.4

a

IN "N7| HI

3.5 10"8

3 10-8

2.5 10"8

2 10"8 /

/

1.5 10"8 /

1 10"8 /

/

5 10"9 /

|K - N7|

1.5 ■ 10"

1 ■ ID-

S' 10"

0.1 0.2 0.3 0.4

0.5 w

0.1 0.2 0.3 0.4 0.5 w b

Figure 3. The 2D curves of the Rel-E graph of N(0i,w) (a), N(01,02,03,w) (b), and N(0i, 02, w) (c) for the approximate finding obtained through seven iterations and the exact result in the range u € [0,0.5], when 0i = 0.25 (a), 0i = 02 = 03 = 0.25 (b), and 0i = 02 = 0.25 (c)

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c

b

a

Abs. Error

c

Figure 4. The 3D plots of the Abs-E of N(0i ,w) (a), N(01,02,03, w) (b), and N(01,02, w) (c) for the approximate finding obtained through seven iterations and exact result in the ranges w € [0, 0.5] and 0i € [0, 0.5], when 02 = 03 = 0.25 (b), and 02 = 0.25 (c)

Figure 5. The 3D plots of the Rel-E of K(0i,w) (a), K(0i,02,0s,w) (b), and K(0i,62,lS) (c) for the approximate finding obtained through seven iterations and exact result in the ranges u € [0, 0.5] and 01 € [0, 0.5], when 02 = 03 = 0.25 (b), and 02 = 0.25 (c)

b

a

c

vals of Abs-E and Rel-E are shown in Table 2 which are from 1.63156 ■ 10 13 to 2.93588■ 10-3 and from 1.21370■ 10-9 for 1.27164■ 10-3, respectively, to Problem 2. Table 3 shows the intervals of Abs-E and Rel-E which are from 2.19100 ■ 10-11 to 2.81468 ■ 10-3 and 2.08398 ■ 10-11 for 8.18227 ■ 10-4, respectively, to Problem 3. Tables 1-3 demonstrate that the 7th step approximate solutions to all numerical equations have remarkably minimal Abs-E and Rel-E. So, the suggested method is very useful for the analysis of different FODEs with a physical interest in the areas of applied mathematics and engineering. As shown in Tables 4-6, Rec-E has been used to numerically demonstrate the process by which the approximate solutions of the Problems 1-3 converge to the exact solution for selected values in the range w e [0,1]. As the order of the fractional derivative is increased, the approximate solution of the seven iterations produced using the suggested method quickly converges to the exact solution. The graphical and numerical findings show the accuracy and reliability of the LRPSM.

Table 1 displays the Abs-E and Rel-E at appropriate grid locations in the ranges w e [0, 1.0] and d1 e [0, 1.0] of the approximate solution attained from the seven iterations and the exact solution to Problem 1 at ft = 1.0 using the LRPSM.

Table 2 displays the Abs-E and Rel-E at appropriate grid locations in the ranges w e [0,1.0], 01 e [0,1.0], 6>2 e [0,1.0] as well as 6>3 e [0,1.0] of the ap-

Table 1

The Abs-E and Rel-E for Problem 1

(0i,w) Abs. Errors Rel. Errors

(0.05,0.05) 2.29781 10-11 2.07914 • 10-11

(0.15,0.15) 1.87820 10-8 1.39140 • 10-8

(0.25,0.25) 4.51442 10-7 2.73814 • 10-7

(0.35,0.35) 3.81249 10-6 1.89322 • 10-6

(0.45,0.45) 1.93189 10-5 7.85450 • 10-6

(0.55, 0.55) 7.22544 10-5 2.40514 • 10-5

(0.65,0.65) 2.20912 10-4 6.02057 • 10-5

(0.75,0.75) 5.85105 10-4 1.30554 • 10-4

(0.85,0.85) 1.39181 10-3 2.54261 • 10-4

(0.95,0.95) 3.04568 10-3 4.55539 • 10-4

Table 2

The Abs-E and Rel-E for Problem 2

(0i,02,#3,w) Abs. Errors Rel. Errors

(0.05,0.05,0.05, 0.05) 1.63156 • 10- 13 1.21370 10- 9

(0.15,0.15,0.15, 0.15) 1.07593 10- -9 2.59356 10- 7

(0.25,0.25,0.25, 0.25) 6.44068 10- 8 2.97104 10- 6

(0.35,0.35,0.35, 0.35) 9.56001 10- -7 1.43769 10- 5

(0.45,0.45,0.45, 0.45) 7.18225 10- 6 4.58092 10- 5

(0.55,0.55,0.55, 0.55) 3.59959 10- 5 1.14039 10- 4

(0.65,0.65,0.65, 0.65) 1.37909 10- 4 2.41227 10- 4

(0.75,0.75,0.75, 0.75) 4.36368 10- 4 4.54630 10- 4

(0.85,0.85,0.85, 0.85) 1.19656 10- 3 7.86128 10- 4

(0.95,0.95,0.95, 0.95) 2.93588 10- 3 1.27164 10- 3

Table 3

The Abs-E and Rel-E for Problem 3

(0!,02,w) Abs. Errors Rel. Errors

(0.05, 0.05, 0.05) 2.19100 • 10-11 2.08398 • 10-11

(0.15,0.05, 0.15) 1.65204 10-8 1.41915 • 10-8

(0.25, 0.05, 0.25) 3.73431 10-7 2.88416 • 10-7

(0.35, 0.05, 0.35) 3.02361 10-6 2.08615 • 10-6

(0.45, 0.05, 0.45) 1.49760 10-5 9.15876 • 10-6

(0.55, 0.05, 0.55) 5.58162 10-5 2.99928 • 10-5

(0.65, 0.05, 0.65) 1.73376 10-4 8.10919 • 10-5

(0.75,0.05, 0.75) 4.75627 10-4 1.91749 • 10-4

(0.85, 0.05, 0.85) 1.19473 10-3 4.11041 • 10-4

(0.95, 0.05, 0.95) 2.81468 10-3 8.18227 • 10-4

Table 4

The Rec-E for K(01 , w) at different values of ft for Problem 1

(0i, w) ft = 0.7 ft = 0.8 ft = 0.9 ft= 1.0

(0.02,0.02) 9.92308 ■ 10-8 6.80134 ■ 10-9 4.41026 10- 10 2.72054 10- 11

(0.12,0.12) 5.80237 ■ 10-5 9.74157 ■ 10-6 1.54730 ■ 10- 6 2.33798 ■ 10- -7

(0.22,0.22) 5.35032 ■ 10-4 1.21625 ■ 10-4 2.61571 ■ 10- 5 5.35152 ■ 10- 6

(0.32,0.32) 2.19460 ■ 10-3 6.01676 ■ 10-4 1.56060 ■ 10- 4 3.85073 ■ 10- 5

(0.42,0.42) 6.28249 ■ 10-3 1.97328 ■ 10-3 5.86366 ■ 10- 4 1.65756 ■ 10- 4

(0.52,0.52) 1.46622 ■ 10-2 5.12431 ■ 10-3 1.69430 ■ 10- 3 7.39038 ■ 10- 4

(0.62,0.62) 2.99909 ■ 10-2 1.14451 ■ 10-2 4.13208 ■ 10- 3 1.80237 ■ 10- 3

(0.72,0.72) 5.59386 ■ 10-2 2.30044 ■ 10-2 8.95017 ■ 10- 3 3.90397 ■ 10- 3

(0.82,0.82) 9.74598 ■ 10-2 4.27726 ■ 10-2 1.77593 ■ 10- 2 7.74645 ■ 10- 3

(0.92,0.92) 1.61125 ■ 10-1 7.49016 ■ 10-2 3.29412 ■ 10- 2 1.43686 ■ 10- 2

proximate solution obtained from the seven iterations and the exact solution to Problem 2 at P = 1.0 using the LRPSM.

Table 3 displays the Abs-E and Rel-E at appropriate grid locations in the ranges w e [0,1.0], 01 e [0,1.0] as well as 02 e [0,1.0] of the approximate solution obtained from the seven iterations and the exact solution to Problem 3 at ft = 1.0 using the LRPSM.

Table 4 shows the Rec-E between the approximate solution attained from the seven iterations and exact solutions of Problem 1 acquired by LRPSM at appropriate grid locations in the ranges w e [0,1.0], and 01 e [0,1.0].

Table 5 shows the Rec-E between the approximate solution obtained from the seven iterations and exact solutions of Problem 2 acquired by LRPSM at appropriate grid locations in the ranges w e [0,1.0], 01 e [0,1.0], 02 e [0,1.0], and 03 e [0,1.0].

Table 6 shows the Rec-E between the approximate solution from the 5th iteration and exact solutions of Problem 3 acquired by LRPSM at appropriate grid locations in the ranges w e [0,1.0], 01 e [0,1.0], and 02 e [0,1.0].

6. Conclusion. We used the Laplace transform with the residual power series method to solve time-fractional partial differential equations with variable coefficients in the sense of the Gerasimov-Caputo fractional derivative. Graphics and tables show that the 7th step approximate and exact solutions are in perfect agreement, which demonstrated the efficiency and reliability of the Laplace residual power series method.

Finally, in conclusion, the main features of our recommended method are the following. The residual power series method is useful for obtaining approximate analytical solutions to fractional order problems, but it requires the residual function's (n — 1)yS derivative to determine the coefficients of the series solution, whereas more widely used methods such as the homotopy perturbation, varia-tional iterational, and Adomian decomposition methods require integration. We are all aware of how challenging it is to find the fractional derivatives and the integration, but our method only requires the concept of an infinite limit, which is relatively simple. Therefore, the problem can be solved using our recommended method, which provides a quick and simple way to figure out the coefficients of the series solution. It is not essential to make any significant physical or parametric assumptions related to the problem. Therefore, our method overcomes some of

The Rec-E for N(0i,02,w) at different values of ß for Problem 2

Table 5

(01, 02, 03, U) ß = 3.7 ß = 3.8 ß = 0.9 ß = L.O

(0.02, 0.02, o.02, 0.02) 3.89064 io- ll 2.66667 io- 12 1.72917- 10- 13 1.06667 lo- 14

(0.12,0.12,0.12,0.12) 7.41059 • 10" -7 1.24416 • 10- -7 1.97616 • 10- -8 2.98598 • lo- -9

(0.22,0.22,0.22,0.22) 2.07817 • 10" -5 4.72416 • 10- -6 1.01599 • 10- -6 2.07863 • lo- -7

(0.32,0.32,0.32,0.32) 1.63185 • 10" -4 4.47392 • 10- -5 1.16043 • 10- -5 2.86331 • lo- -6

(0.42,0.42,0.42,0.42) 7.28160 • 10" -4 2.28710 • 10- -4 6.79616 • 10- -5 1.92116 • lo- -5

(0.52,0.52,0.52,0.52) 2.35708 • 10- -3 8.23775 • 10- -3 2.72374 • 10- -4 8.56726 • 10- -5

(0.62,0.62,062,0.62) 6.20169 • 10- -3 2.36668 • 10- -3 8.54455 • 10- -4 2.93468 • 10- -4

(0.72,0.72,0.72,0.72) 1.41151 • 10- -2 5.80475 • 10- -3 2.25842 • 10- -3 8.35884 • 10- -4

(0.82,0.82,0.82,0.82) 2.88624 • 10- -2 1.26669 • 10- -2 5.25936 • 10- -3 2.07738 • 10- -3

(0.92,0.92,0.92,0.92) 5.43487 • lo- -2 2.52648 • 10- -2 1.11113 • 10- -2 4.64872 • 10- -3

Table 6

The Rec-E for N(0i,02,w) at different values of ß for Problem 3

(Ol,0 2,w) ß = 0.7 ß = 0.8 ß = 3.9 ß = L.O

(0.02,0.02,0.02) 9.73048 io- -8 6.66933 10- -9 4.32466 lo- 10 2.66773 io- ii

(0.12,0.12,0.12) 5.22088 io- -5 8.76532 10- -6 1.39224 • 10- -6 2.10368 • io- -7

(0.22,0.22,0.22) 5.06660 io- -4 1.02447 10- -4 2.20326 • 10- -5 4.50767 • io- -6

(0.32,0.32,0.32) 1.76544 io- -3 4.84017 10- -4 1.25542 • 10- -4 3.09771 • io- -5

(0.42,0.42,0.42) 4.92422 io- -3 1.54666 10- -3 4.59594 • 10- -4 1.29920 • io- -4

(0.52,0.52,0.52) 1.14235 io- -2 3.99241 10- -3 1.32005 • 10- -3 4.15211 • io- -4

(0.62,0.62,0.62) 2.36957 io- -2 9.04270 10- -3 3.26474 • 10- -3 1.12130 • io- -3

(0.72,0.72,0.72) 4.57254 io- -2 1.88043 10- -2 7.31607 • 10- -3 2.70782 • io- -3

(0.82,0.82,0.82) 8.40860 io- -2 3.69032 10- -2 1.53223 • 10- -2 6.05212 • 10" -3

(0.92,0.92,0.92) 1.49692 10" -1 6.95868 10- -2 3.06038 • 10" -2 1.28040 • lO- -2

the inherent limitations of conventional perturbation approaches and works with both weak and strongly nonlinear systems. The He and Adomian polynomials do not need our method, so nonlinear problems can be solved with a relatively small number of calculations. As a result, it performs noticeably better than various series solution methods based on Adomian decomposition and homotopy perturbation methods. In contrast to various analytic approximate methods, the Laplace residual power series method may give analytical expansion solutions for both linear and nonlinear problems without the need for perturbation, linearization, or discretization.

Therefore, our method is simple to apply, accurate and reliable in its results. In the future, as new fractional-order problems emerge in various situations, we plan to solve them using the Laplace residual power series method.

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Competing interests. The authors declare that they have no competing interests. Authors' contributions and responsibilities. The authors declare that the study was realized in collaboration with equal responsibility. All authors read and approved the final manuscript.

Availability of Data and Materials. No data were generated or analyzed during the current study.

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Вестн. Сам. гос. техн. ун-та. Сер. Физ.-мат. науки. 2023. Т. 27, № 2. С. 214-240 ISSN: 2310-7081 (online), 1991-8615 (print) d https://doi.org/10.14498/vsgtu2009

EDN: XAVFLR

УДК 519.642.2

Эффективный метод аналитического исследования линейных и нелинейных дробно-временных уравнений в частных производных с переменными коэффициентами

М. I. ЫаааЬ12, А. Акдп13'4'5, Е. Уп. Рговчпгуакоу6'7'8'9

Правительственный колледж Университета, Лахор, 54600, Пакистан. Национальный колледж делового администрирования и экономики, Лахор, 54660, Пакистан.

Ливанский Американский университет, Бейрут, 1102 2801, Ливан. Университет Сиирта, Сиирт, 56100, Турция. 5 Ближневосточный университет, Никосия, 99138, Турция.

Уральский федеральный университет, Екатеринбург, 620137, Россия. Институт машиноведения УрО РАН, Екатеринбург, 620049, Россия. Уральский государственный университет путей сообщения, Екатеринбург, 620034, Россия.

Удмуртский федеральный исследовательский центр УрО РАН, Ижевск, 426067, Россия.

Аннотация

Метод остаточных степенных рядов эффективен для получения приближенных аналитических решений дифференциальных уравнений дробного порядка. Вычисление дробной производной для коэффициентов степенного ряда, аппроксимирующего точное решение дифференциального уравнения, является недостатком этого метода. Другие известные методы приближенного интегрирования, такие как гомотопическое возмущение, разложение Адомиана и методы вариационных итераций, основываются на интегрировании для получения степенного ряда. Известна сложность вычисления дробных производных и интегрирования функций при построении степенного ряда для решения уравнений математической физики дробного порядка, поэтому использование упомянутых выше методов ограничено спецификой решаемой задачи. В настоящей статье получены приближенные и точные аналитические решения уравнений в частных производных переменными коэффициентами при использовании метода рядов остаточных степеней Лапласа в смысле дробной производной Герасимова-Капуто для времени. Этот метод

Дифференциальные уравнения и математическая физика Научная статья

© Коллектив авторов, 2023 © СамГТУ, 2023 (составление, дизайн, макет)

3 ©® Контент публикуется на условиях лицензии Creative Commons Attribution 4.0

International (https://creativecommons.org/licenses/by/4.0/deed.ru) Образец для цитирования

Liaqat M. I., A kg ul A., Prosviryakov E. Yu. An efficient method for the analytical study

of linear and nonlinear time-fractional partial differential equations with variable coefficients, Vestn. Samar. Gos. Tekhn. Univ., Ser. Fiz.-Mat. Nauki [J. Samara State Tech. Univ., Ser. Phys. Math. Sci.], 2023, vol. 27, no. 2, pp. 214-240. EDN: XAVFLR. DOI: 10.14498/vsgtu2009.

Сведения об авторах

Muhammad Imran Liaqat © https://orcid.org/0000-0002-5732-9689

PhD Student, Abdus Salam School of Mathematical Sciences1; Lecturer, Dept. of Mathematics2; e-mail: [email protected]

помог преодолеть ограничения упомянутых выше способов интегрирования уравнений дробного порядка. Метод остаточных степенных рядов Лапласа лучше использовать при вычислении коэффициентов членов в решении ряда, применяя принцип прямого предела на бесконечности. Он также более эффективен, чем различные методы решения, если не использовать полиномы Адомиана и Не для решения нелинейных задач дробного порядка. В статье исследуются относительные, повторяющиеся и абсолютные ошибки для трех задач математической физики для оценки достоверности предложенного метода. Результаты показывают, что сконструированный метод является альтернативой различным методам для построения решения рядами при решении уравнений в частных производных с дробным временем.

Ключевые слова: преобразование Лапласа, метод остаточных степенных рядов, уравнение в частных производных, производная Герасимова-Капуто.

Получение: 18 марта 2023 г. / Исправление: 12 июня 2023 г. / Принятие: 19 июня 2023 г. / Публикация онлайн: 27 июня 2023 г.

Конкурирующие интересы. Авторы заявляют, что у них нет конкурирующих интересов.

Авторский вклад и ответственность. Авторы заявляют, что исследование было проведено в сотрудничестве с равной ответственностью. Все авторы прочитали и одобрили окончательную рукопись.

Доступность данных и материалов. В ходе текущего исследования не было получено или проанализировано никаких данных.

Ali Akgulfa ©https://orcid.org/0000-0001-9832-1424

PhD in Math, Full Professor; Dept. of Computer Science and Mathematics3; Dept. of Mathematics, Art and Science Faculty4; Dept. of Mathematics, Mathematics Research Center5; e-mail: [email protected]

Evgenii Yu. Prosviryakov © https://orcid.org/0000-0002-2349-7801

Dr. Phys. & Math. Sci.; Dept. of Information Technologies and Control Systems6; Sect. of Nonlinear Vortex Hydrodynamics7; Dept. of Natural Sciences8; Lab. of Physical and Chemical Mechanics9; e-mail: [email protected]

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