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Computer Physics Communications 180 (2009) 1539–1544 Contents lists available at ScienceDirect Computer Physics Communications www.elsevier.com/locate/cpc New analytical method for solving Burgers’ and nonlinear heat transfer equations and comparison with HAM M.M. Rashi di , E. Erfani Engineering Faculty of Bu-Ali Sina University, PO Box 651 75-41 61 Hamedan, Iran a r t i c l e i n f o a b s t r a c t  Article history: Received 22 January 2009 Accepted 15 April 2009 Available online 17 April 2009 Keywords: Differential transform method (DTM) Burgers’ equation Nonlinear differential equation Homotopy analysis method (HAM) Fin In this study, we present a numerical comparison between the differential transform method (DTM) and the homotopy anal ysis method (HAM) for solving Burgers’ and nonli near heat transfer problems. The rst differential equation is the Burgers’ equation serves as a useful model for many interesting problems in applied mathematics. The second one is the modeling equation of a straight n with a temperature depe ndent therma l condu ctiv ity . In orde r to show the effec tiv enes s of the DTM, the results obtained from the DTM is compared with available solutions obtained using the HAM [M.M. Rashidi, G. Domairry, S. Dinarvand, Commun. Nonlinear Sci. Numer. Simul. 14 (2009) 708–717; G. Domairry, M. Fazeli, Commun. Nonl inea r Sci. Numer . Simu l. 14 (2009) 489–499] and whit exa ct solutions . The method can easi ly be applied to many linear and nonlinear problems. It illustrates the validity and the great potential of the diffe rent ial tra nsfor m meth od in solv ing nonli near part ial diffe rent ial equa tion s. The obta ined res ults reveal that the technique introduced here is very effective and convenient for solving nonlinear partial diffe rent ial equatio ns and nonli near ordina ry diffe rent ial equ atio ns that we are found to be in good agreement with the exact solutions. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Most phenomena in real world are described through nonlinear equ atio ns. Non linea r pheno mena play impo rtan t role s in appli ed mathematics, physics and in engineering problems in which each para met er vari es depen ding on differ ent fact ors. The impo rtance of obtaining the exact or approximate solutions of nonlinear par- tial differential equations (NLPDEs) in physics and mathematics, it is sti ll a hot spo t to seek new me thods to obta in new exact or approximate solutions. Large class of nonlinear equations does not have a precise analytic solution, so numerical methods have largely bee n use d to han dle the se equa tio ns. The re are also some ana- lytic techniques for nonlinear equations. Some of the classic ana- lytic methods are the Lyapunov’s articial small parameter method, pertu rbation tec hniq ues and  δ -ex pansi on method. In the rece nt years, many authors mainly had paid attention to study solutions of nonlinear partial differential equations by using various meth- ods. Among these are the Adomian decomposition method (ADM), tanh meth od, homo top y pertu rbati on met hod (HPM) , sinh– cosh method, HAM, DTM and variational iteration method (VIM). In 1992, Lia o  [1]  emp loyed the bas ic ide as of homotopy in topology to propose a general analytic method for nonlinear prob- lems, namel y the HAM. Based on homoto py of topo logy , the va- *  Corresponding author. Tel.: +98 811 8257409; fax: +98 811 8257400. E-mail address: [email protected] (M.M. Rashidi). lidity of the HAM is ind epe nde nt of whe the r or not the re exist small parameters in the considered equation. Therefore, the HAM can overcome the foregoing restrictions of perturbation methods. In recent years, the HAM has been successfully employed to solve man y types of nonli near problems, see  [2–6]  and the refe rences therein. The concept of differential transform method method was rst intro duced by Zhou  [7]  in 1986 and it wa s us ed to sol ve bo th linear and nonlinear initial value problems in electric circuit anal- ysis. The main advantage of this method is that it can be applied direc tly to NLPDE s witho ut req uirin g linea rizat ion, discretiza tion , or pertu rbat ion. It is a semi analytic al–numerical tech niqu e that formulizes Tay lor serie s in a very different manner . This method constructs, for differential equations, an analytical solution in the form of a polynomial. Not like the traditional high order Taylor se- ries method that req uires symbo lic comp utation, the DTM is an iter ati ve proc edur e for obta ining Ta ylor serie s solutions. Anot her important advantage is that this method reducing the size of com- putational work while the Taylor series method is computationally taken long time for large orders. This method is well addressed in [23–30]. The Burgers’ equation is a nonlinear partial differential equation of second order. Burgers’ equation was rst introduced by Bateman [8]  and then treated by Burgers’  [9,10]  as a mathematical model for turbulenc e. This equati on has a larg e vari ety of applic atio ns in mode ling of wat er in unsaturated soil, dynamic of soil water , statistics of ow problems, mixing and turbulent diffusion, cosmol- 0010-4655/$ – see front matter  © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.cpc.2009.04.009

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Computer Physics Communications 180 (2009) 1539–1544

Contents lists available at ScienceDirect

Computer Physics Communications

www.elsevier.com/locate/cpc

New analytical method for solving Burgers’ and nonlinear heat transfer equations

and comparison with HAM

M.M. Rashidi ∗, E. Erfani

Engineering Faculty of Bu-Ali Sina University, PO Box 65175-4161 Hamedan, Iran

a r t i c l e i n f o a b s t r a c t

Article history:

Received 22 January 2009Accepted 15 April 2009

Available online 17 April 2009

Keywords:

Differential transform method (DTM)

Burgers’ equation

Nonlinear differential equation

Homotopy analysis method (HAM)

Fin

In this study, we present a numerical comparison between the differential transform method (DTM) and

the homotopy analysis method (HAM) for solving Burgers’ and nonlinear heat transfer problems. The

first differential equation is the Burgers’ equation serves as a useful model for many interesting problems

in applied mathematics. The second one is the modeling equation of a straight fin with a temperature

dependent thermal conductivity. In order to show the effectiveness of the DTM, the results obtained

from the DTM is compared with available solutions obtained using the HAM [M.M. Rashidi, G. Domairry,

S. Dinarvand, Commun. Nonlinear Sci. Numer. Simul. 14 (2009) 708–717; G. Domairry, M. Fazeli, Commun.

Nonlinear Sci. Numer. Simul. 14 (2009) 489–499] and whit exact solutions. The method can easily be

applied to many linear and nonlinear problems. It illustrates the validity and the great potential of the

differential transform method in solving nonlinear partial differential equations. The obtained results

reveal that the technique introduced here is very effective and convenient for solving nonlinear partial

differential equations and nonlinear ordinary differential equations that we are found to be in good

agreement with the exact solutions.

© 2009 Elsevier B.V. All rights reserved.

1. Introduction

Most phenomena in real world are described through nonlinear

equations. Nonlinear phenomena play important roles in applied

mathematics, physics and in engineering problems in which each

parameter varies depending on different factors. The importance

of obtaining the exact or approximate solutions of nonlinear par-

tial differential equations (NLPDEs) in physics and mathematics, it

is still a hot spot to seek new methods to obtain new exact or

approximate solutions. Large class of nonlinear equations does not

have a precise analytic solution, so numerical methods have largely

been used to handle these equations. There are also some ana-

lytic techniques for nonlinear equations. Some of the classic ana-

lytic methods are the Lyapunov’s artificial small parameter method,perturbation techniques and δ-expansion method. In the recent

years, many authors mainly had paid attention to study solutions

of nonlinear partial differential equations by using various meth-

ods. Among these are the Adomian decomposition method (ADM),

tanh method, homotopy perturbation method (HPM), sinh–cosh

method, HAM, DTM and variational iteration method (VIM).

In 1992, Liao [1] employed the basic ideas of homotopy in

topology to propose a general analytic method for nonlinear prob-

lems, namely the HAM. Based on homotopy of topology, the va-

* Corresponding author. Tel.: +98 811 8257409; fax: +98 811 8257400.

E-mail address: [email protected] (M.M. Rashidi).

lidity of the HAM is independent of whether or not there exist

small parameters in the considered equation. Therefore, the HAM

can overcome the foregoing restrictions of perturbation methods.

In recent years, the HAM has been successfully employed to solve

many types of nonlinear problems, see [2–6] and the references

therein.

The concept of differential transform method method was first

introduced by Zhou [7] in 1986 and it was used to solve both

linear and nonlinear initial value problems in electric circuit anal-

ysis. The main advantage of this method is that it can be applied

directly to NLPDEs without requiring linearization, discretization,

or perturbation. It is a semi analytical–numerical technique that

formulizes Taylor series in a very different manner. This method

constructs, for differential equations, an analytical solution in theform of a polynomial. Not like the traditional high order Taylor se-

ries method that requires symbolic computation, the DTM is an

iterative procedure for obtaining Taylor series solutions. Another

important advantage is that this method reducing the size of com-

putational work while the Taylor series method is computationally

taken long time for large orders. This method is well addressed in

[23–30].

The Burgers’ equation is a nonlinear partial differential equation

of second order. Burgers’ equation was first introduced by Bateman

[8] and then treated by Burgers’ [9,10] as a mathematical model

for turbulence. This equation has a large variety of applications

in modeling of water in unsaturated soil, dynamic of soil water,

statistics of flow problems, mixing and turbulent diffusion, cosmol-

0010-4655/$ – see front matter © 2009 Elsevier B.V. All rights reserved.

doi:10.1016/j.cpc.2009.04.009

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ogy and seismology [11–13]. The Burgers’ equation is a nonlinear

equation, very similar to the Navier–Stokes equation and there is

analogy between the Burgers’ equation and Navier–Stokes equation

due to the form of nonlinear terms. This single equation has a con-

vection term, a diffusion term, and a time-dependent term.

In Burgers’ equation, discontinuities may appear in finite time,

even if the initial condition is smooth. They give rise to the phe-

nomenon of shock waves with important applications in physics[14]. These properties make Burgers’ equation a proper model for

testing numerical algorithms in flows where severe gradients or

shocks are anticipated. Several numerical methods to solve this

system have been given such as algorithms based on cubic spline

function technique [15], the explicit–implicit method [16], Adomi-

an’s decomposition method [17]. The variational iteration method

was used to solve the 1D Burgers’ and coupled Burgers’ equations

[18]. Rashidi and et al. [19] used the HAM to solve Burgers’ equa-

tion.

Fins or extended surfaces are frequently used to enhance the

rate of heat transfer from the primary surface. The rectangular fin

is widely used, probably, due to simplicity of its design and it is

less difficult in manufacturing process. However, it is well-known

fact that the rate of heat transmission from a fin base diminishesalong its length. Kern and Kraus [20] made an extensive review on

this issue. Aziz and Hug [21] used the regular perturbation method

and a numerical solution method to compute a closed form so-

lution for a straight convective fin with temperature-dependent

thermal conductivity. The HAM was used by Domairry and Fazeli

to solve Rectangular purely convective fin with temperature depen-

dent thermal conductivity [22].

In this paper, we extend the application of the differential

transform method to construct analytical approximate solutions

of the Burgers’ equation (5) and the modeling equation of a

straight fin with a temperature-dependent thermal conductivity

equation (15). Then we compare our results with the previously

obtained results by using the HAM in [19,22] and exact solutions.

With this technique, it is possible to obtain highly accurate resultsor exact solutions for differential equations.

2. Basic idea of the differential transform method

The basic definitions and fundamental operations of the two-

dimensional differential transform are defined in [23–30]. Consider

a function of two variable w( x, y) be analytic in the domain Ω and

let ( x, y) = ( x0, y0) in this domain. The function w( x, y) is then

represented by one series whose centre at located at w( x0, y0).

The differential transform of the function is the form

W (k, h) =1

k!h!

∂k+h w( x, y)

∂k x∂h y

( x0, y0)

, (1)

where w( x, y) is the original function and W (k, h) is the trans-

formed function. The transformation is called T-function and the

lower case and upper case letters represent the original and trans-

formed functions respectively. Then its inverse transform is defined

as

w( x, y) =

k=0

h=0

W (k, h)( x− x0)k( y − y0)h. (2)

The relations (1) and (2) imply that

w( x, y) =

∞k=0

∞h=0

1

k!h!

∂k+h w( x, y)

∂k x∂h y

( x0, y0)

( x− x0)k( y − y0)h. (3)

In a real application and when ( x0, y0) are taken as (0, 0), then

the function w( x, y) is expressed by a finite series and Eq. (2) can

be written as

w( x, y) ∼=

mk=0

nh=0

W (k, h) xk yh, (4)

in addition, Eq. (4) implies that ∞

k=m+1∞

h=n+1 W (k, h) xk yh is

negligibly small. Usually, the values of m and n are decided byconvergences of the series coefficients.

3. Application

3.1. The Burgers’ equation

Consider the Burgers’ equation [31]

ut + uu x − u xx = 0, x ∈ R, (5)

with the exact solution [32]

u( x, t ) =1

2 −

1

2 tanh

1

4

x−

1

2t

, (6)

and with the initial condition

u( x, 0) =1

2 −

1

2 tanh

x

4

. (7)

Taking the two-dimensional transform of Eq. (5) by using the re-

lated definitions in Table 1, we have

(h + 1)U (k, h + 1)+

kr =0

hs=0

(k − r + 1)U (r , h − s)U (k − r + 1, s)

− (k + 1)(k + 2)U (k + 2, h) = 0, (8)

by applying the differential transform into Eq. (7), the initial trans-

formation coefficients are thus determined by

Table 1

The operations for the two-dimensional differential transform method.

Original function Transformed function

w( x, y) = u( x, y)± v( x, y) W (k, h) = U (k, h)± V (k, h)

w( x, y) = λu( x, y) W (k, h) = λU (k, h), λ is a constant

w( x, y) = ∂u( x, y)

∂ x W (k, h) = (k+ 1)U (k+ 1, h)

w( x, y) = ∂u( x, y)

∂ y W (k, h) = (h + 1)U (k, h + 1)

w( x, y) = ∂ r +s u( x, y)

∂ xr ∂ ys W (k, h) = (k+ 1)(k + 2) . . . (k+ r )(h + 1)(h + 2) . . . (h + s)U (k+ r , h+ s)

w( x, y) = u( x, y)v( x, y) W (k, h) =k

r =0

hs=0 U (r , h − s)V (k − r , s)

w( x, y) = ∂u( x, y)

∂ x∂ v( x, y)

∂ x W (k, h) =k

r =0

hs=0(r + 1)(k − r + 1)U (r + 1, h − s)V (k− r + 1, s)

w( x, y) = ∂u( x, y)

∂ x∂ v( x, y)

∂ y W (k, h) =

kr =0

hs=0(k− r + 1)(h − s + 1)U (k − r , s)V (r , h− s + 1)

w( x, y) = u( x, y)∂ v( x, y)

∂ x W (k, h) =kr =0 h

s=0(k− r + 1)U (r , h − s)V (k − r + 1, s)

w( x, y) = u( x, y)∂ 2 v( x, y)

∂ x W (k, h) =k

r =0

hs=0(k− r + 2)(k − r + 1)U (r , h− s)V (k− r + 2, s)

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∞k=0

U (k, 0) xk=

1

2 −

x

8 +

x3

384 −

x5

15360 +

17 x7

10321920

−31 x9

743178240 +

691 x11

653996851200 + · · · . (9)

Hence from Eq. (9)

U (k, 0) = 0, if k = 2, 4, 6, . . . ,

U (1, 0) =−1

8, U (3, 0) =

1

384,

U (5, 0) =−1

15360, . . . . (10)

Substituting Eq. (10) in Eq. (8), and by recursive method we

can calculating another values of U (k, h), some results are listed as

follows in Table 2. Hence, substituting all U (k, h) into Eq. (4) we

have series solution as below

Table 2

Some values of U (k, h) of Example 3.1.

U (1, 1) = 0 U (2, 3) = 13!×211 U (5, 6) = 691

3!3×224×52 U (1, 8) =− 31

3!2×224×5×7

U (2, 2) = 0 U (3, 2) =− 1

3!×210 U (6, 5) =− 691

3!3×223×52 U (8, 1) = 31

3!2×217×5×7

U (3, 3) = 0 U (3, 4) = 173!×217 U (2, 5) =−

173!×219×5

U (3, 6) =− 31

3!3×219×5

u( x, t ) ∼=

mk=0

nh=0

U (k, h) xkt h

= U (0, 0)+ U (1, 0) x+ U (0, 1)t

+ U (1, 1) xt +· · · + U (m, n) xmt n

=1

2

+t

16

−t 3

3072

+t 5

491520

− x

8

+t 2 x

512

−t 4 x

49152

−tx2

256

+t 3 x2

12888 −

17t 5 x2

15728640 +

x3

384 −

t 2 x3

6144 +

17t 4 x3

4718592 +

tx4

6144

−17t 3 x4

2359296 +

31t 5 x4

188743680 −

x5

15360

+17t 2 x5

1966080 −

31t 4 x5

94371840 + · · · . (11)

Our approximation has one more interesting property, if we ex-

pand exact solution (6) using Taylor’s expansion about (0, 0), we

have the series same as the our approximation (11).

In Fig. 1, we study the diagrams of the results obtained by the

DTM for m = 50, n = 50 in comparison with the HAM [19] and

exact solution (6).

Note that the solution series obtained by the HAM contains theauxiliary parameter h, which provides us with a simple way to ad-

just and control the convergence of the solution series. As pointed

Fig. 1. The results obtained by the DTM (m = 50, n = 50) Eq. (11) and the HAM [19] by 9th-order approximate solution, in comparison with the exact solution (6), when

5 t 12, (a) x = 0.25; (b) x = 0.75; (c) x = 1; (d) x = 1.5.

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Table 3

Comparison of the exact solution (6) whit the DTM (m = 50, n = 50) and the HAM (h =−0.6) by 9th-order approximate solution in case of x = 0.5, x = 1.5 and 0 t 12.

t x = 0.5 x = 1.5

Exact HAM (h =−0.6) DTM Exact HAM (h =−0.6) DTM

1 0.500000000 0.499967668 0.500000000 0.377540668 0.377496222 0.377540668

2 0.562176500 0.562186654 0.562176500 0.437823499 0.437785782 0.437823499

3 0.622459331 0.622618884 0.622459331 0.500000000 0.500133672 0.499999999

4 0.679178699 0.679494353 0.679178699 0.562176500 0.562684851 0.5621765005 0.731058578 0.731289069 0.731058578 0.622459331 0.623385326 0.622459331

6 0.777299861 0.776880106 0.777299861 0.679178699 0.680114881 0.679178699

7 0.817574476 0.815694315 0.817574476 0.731058578 0.730852749 0.731058578

8 0.851952801 0.847843276 0.851952801 0.777299861 0.773875815 0.777299861

9 0.880797077 0.874236662 0.880797060 0.817574476 0.807988448 0.817574479

10 0.904650535 0.896665720 0.904646851 0.851952801 0.832782589 0.851953323

11 0.924141819 0.917848146 0.923677794 0.880797077 0.848926292 0.880854270

12 0.939913349 0.941425185 0.901792839 0.904650535 0.858478394 0.908702365

Fig. 2. The comparison of the errors in answers results by the DTM ( m = 50, n = 50)

and the HAM (h =−0.6) by 9th-order approximate solution at t = 10.

in [19], the valid region of h in this case is −1.6 < h < −0.4. Whenh =−1, the solution by the HAM is as the same solution series ob-

tained by HPM, which proposed in 1998 by Dr. He [33]. Therefore,

the HAM logically contains the HPM. We can find that the best

value of h in this case is −0.6.

In Table 3, we present a numerical comparison between the

HAM (h =−0.6) by 9th-order approximate solution, the DTM (m =

50, n = 50), and exact solution (6) in this case of x = 0.5, x = 1.5

and 0 t 12.

Table 3 indicates that the results obtained by the DTM for the

case of 0 t 8 have nine digits precision whit the exact solu-

tions.

In Figs. 2 and 3, we present the comparison of the errors

in answers results by the DTM (m = 50, n = 50) and the HAM

(h =−0.6) by 9th-order approximate solution at t = 10 and t = 11respectively for the case of −1 x 1. Considering these two fig-

ures, we find out that errors of the DTM are very less than those

of the HAM even for large t .

3.2. Rectangular purely convective fin with temperature dependent

thermal conductivity

Consider a straight fin with a temperature-dependent thermal

conductivity, arbitrary constant cross-sectional area Ac , perimeter

P , and length b (see Fig. 4). The fin is attached to a base surface of

temperature T b , extends into a fluid of temperature T a and its tip

is insulated. The one-dimensional energy balance equation is given

Ac d

dx

k(T )

dT

dx

− P h(T b − T a) = 0. (12)

Fig. 3. The comparison of the errors in answers results by the DTM ( m = 50, n = 50)

and the HAM (h =−0.6) by 9th-order approximate solution at t = 11.

Fig. 4. Geometry of a straight fin.

The thermal conductivity of the fin material is assumed a linear

function of temperature according to

k(T ) = ka

1+ λ(T − T a)

, (13)

where ka is the thermal conductivity at the ambient fluid temper-

ature of the fin and k is the parameter describing the variation of

the thermal conductivity.

Employing the following dimensionless parameters

θ =T − T a

T b − T a, ζ =

x

b, β = λ(T b − T a), ψ =

h P b2

ka Ac

1/2

.

(14)

The formulation of the problem reduces to

d2θ

dζ 2 + βθ

d2θ

dζ 2 + β

2−ψ 2θ = 0, (15a)

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Table 4

Comparison of the dimensionless temperature errors in answers results by the DTM (k = 15) and the HAM by 12th-order approximate solution for the case of constant

thermal conductivity, i.e. β = 0.

ζ ψ = 0.5 ψ = 1

DTM HAM (h =−1) HAM (h =−0.92) DTM HAM (h =−1) HAM (h =−0.791)

0 0.000000000 1.3600 × 10−12 4.8849 × 10−15 2.0095 × 10−14 1.7793×10−5 4.5732× 10−11

0.1 0.000000000 1.3433× 10−12 4.6629 × 10−15 2.0317× 10−14 1.7574× 10−5 4.6543× 10−11

0.2 0.000000000 1.2936× 10−

12 4.4408 × 10−

15 2.0539× 10−

14 1.6922×10−

5 4.7738× 10−

11

0.3 0.000000000 1.2121× 10−12 3.1086× 10−15 2.0983 × 10−14 1.5854×10−5 4.5748 × 10−11

0.4 1.1102×10−16 1.1013 × 10−12 2.9976× 10−15 2.1649 × 10−14 1.4395×10−5 3.5230× 10−11

0.5 0.000000000 9.6378 × 10−13 2.3314× 10−15 2.2648 × 10−14 1.2582×10−5 1.0373× 10−11

0.6 0.000000000 8.0147 × 10−13 5.2180× 10−15 2.3869× 10−14 1.0458×10−5 3.2824× 10−11

0.7 1.1102×10−16 6.2105× 10−13 6.7723 × 10−15 2.5091 × 10−14 8.0782×10−6 9.1056× 10−11

0.8 1.1102×10−16 4.2377× 10−13 1.2212 × 10−14 2.5979× 10−14 5.4985×10−6 1.4602× 10−10

0.9 1.1102×10−16 2.1505× 10−13 3.9968 × 10−15 2.3092× 10−14 2.7835×10−6 1.4952× 10−10

1. 0.000000000 6.9944 × 10−15 7.7715× 10−15 0.0000000000 0.000000000 5.3290× 10−15

dζ = 0 at ζ = 0, (15b)

θ = 1 at ζ = 1. (15c)

Taking the one-dimensional transform of Eq. (15a) by using the

related definitions, we have

(k + 1)(k + 2)Θ(k + 2)

+ β

kr =0

(k − r + 2)(k − r + 1)Θ(r )Θ(k − r + 2)

+ β

kr =0

(r + 1)(k − r + 1)Θ(r + 1)Θ(k − r + 1)

−ψ2Θ(k) = 0, (16)

where dimensionless temperature is given by

θ(ζ) =

k=0

Θ (k)ζ k. (17)

Additionally, applying the DTM to Eq. (15b) the boundary condition

is given as follow

Θ(1) = 0, (18)

by assuming

Θ(0) = α, (19)

moreover, substituting Eqs. (18) and (19) into Eq. (16) and by re-

cursive method we can calculating another values of Θ(k), some

results are listed as follows

Θ(k) = 0, if k = 3, 5, 7, . . . ,

Θ(2) =αψ2

2!(1+αβ),

Θ(4) =α(1− 2αβ)ψ 4

4!(1+αβ)3 ,

Θ(6) =α(2αβ − 1)(14αβ − 1)ψ6

6!(1+ αβ)5 ,

Θ(8) =α(2αβ − 1)(1 + 4αβ(112αβ − 19))ψ8

8!(1+ αβ)7 ,

.

.

.. (20)

By applying the boundary condition (15c), we can obtain α .

Hence, substituting all Θ(k) into (17) we have series solutionas below

Fig. 5. The comparison of the dimensionless temperature errors in answers results

by the DTM (k = 15) and the HAM by 12th-order approximate solution (ψ = 1, β =

0)

.

θ(ζ) ∼=

mk=0

Θ(k)ζ k = α +αψ2

2!(1+ αβ)ζ 2 +

α(1− 2αβ)ψ 4

4!(1+αβ)3 ζ 4

+α(2αβ − 1)(14αβ − 1)ψ6

6!(1+ αβ)5 ζ 6

+α(2αβ − 1)(1 + 4αβ(112αβ − 19))ψ8

8!(1+ αβ)7 ζ 8

+· · · . (21)

When the thermal conductivity is constant, i.e. β = 0 Eq. (15)

becomes a linear equation for which analytical solution is avail-

able. The analytical solution for dimensionless temperature distri-

bution θ(ζ) is

θ(ζ)analytical =eψζ + e−ψζ

eψ + e−ψ . (22)

In Table 4, numerical comparison of the dimensionless temper-

ature errors in answers results by the DTM and the HAM [22] were

compared for ψ = 0.5 and ψ = 1. Note that the solution series

obtained by the HAM contains the auxiliary parameter h, which

influence its convergence region and rate. We should therefore fo-

cus on the choice of h by plotting of errors in answers results by

the HAM for some values of h.

As pointed in [22], the valid region of h for the case of ψ = 0.5

and constant thermal conductivity is −1.3 < h < 0 and for the case

of ψ = 1 and constant thermal conductivity is −1.6 < h < −0.1.

In Fig. 5, we present the comparison of the errors in answersresults by the DTM (m = 15) and the HAM (h =−0.78, h =−0.785

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Fig. 6. Comparison for dimensionless temperature variation for ψ = 1.

and h = −0.791) by 12th-order approximate solution for the case

of the constant thermal conductivity.From Table 4 and Fig. 5, it can be concluded that approximate

the DTM expression presented as a solution in this study gives

better results than the HAM approximation. We observe that the

best value of h is −0.791 for the case of (ψ = 1, β = 0) Fig. 5 and

−0.92 for the case of (ψ = 0.5, β = 0).

When conductivity varies whit temperature, Eq. (15) becomes

a nonlinear equation for which analytical solution is not avail-

able. Hence, in this paper a second analysis is also conducted via

the classical fourth-order Runge–Kutta for the purpose of testing

this method. In Fig. 6, dimensionless temperature distribution is

compared for ψ = 1 with various β values. From Fig. 6 it is seen

that, when the problem becomes nonlinear the obtained results by

those the DTM and the HAM agreement with numerical results.

4. Conclusions

In this paper, we presented a reliable algorithm based on

the DTM to solve some nonlinear equations. Some examples are

given to illustrate the validity and accuracy of this procedure. The

present method reduces the computational difficulties of the other

methods (same as the HAM, VIM, ADM and HPM) and all the

calculations can be made simple manipulations. The accuracy of

the method is very good. The method has been applied directly

without requiring linearization, discretization, or perturbation. The

obtained results demonstrate the reliability of the algorithm and

gives it a wider applicability to nonlinear differential equations.

References

[1] S.J. Liao, The proposed homotopy analysis technique for the solution of nonlin-

ear problems, Ph.D. thesis, Shanghai Jiao Tong University, 1992.

[2] S.J. Liao, Beyond Perturbation: An Introduction to Homotopy Analysis Method,

Chapman Hall/CRC Press, Boca Raton, 2003.

[3] M.M. Rashidi, G. Domairry, S. Dinarvand, The homotopy analysis method for

explicit analytical solutions of Jaulent–Miodek equations, Numerical Methods

for Partial Differential Equations 25 (2) (2009) 430–439.

[4] M.M. Rashidi, S. Dinarvand, Purely analytic approximate solutions for steady

three-dimensional problem of condensation film on inclined rotating disk by

homotopy analysis method, Nonlinear Analysis Real World Applications 10 (4)

(2009) 2346–2356.

[5] S.J. Liao, On the homotopy analysis method for nonlinear problems, Appl. Math.

Comput. 147 (2004) 499–513.

[6] T. Hayat, M. Sajid, On analytic solution for thin film flow of a fourth grade fluid

down a vertical cylinder, Phys. Lett. A 361 (2007) 316–322.

[7] J.K. Zhou, Differential Transformation and its Applications for Electrical Circuits,

Huazhong Univ. Press, Wuhan, China, 1986 (in Chinese).

[8] H. Bateman, Some recent researches on the motion of fluids, Mon. WeatherRev. 43 (1915) 163–170.

[9] J.M. Burgers, Mathematical examples illustrating relations occurring in the the-

ory of turbulent fluid motion, Trans. R. Neth. Acad. Sci. Amst. 17 (1939) 1–53.

[10] J.M. Burgers, A Mathematical Model Illustrating the Theory of Turbulence,

in: Advances in Applied Mechanics, vol. I, Academic Press, New York, 1948,

pp. 171–199.

[11] N. Su, J.P.C. Watt, K.W. Vincent, M.E. Close, R. Mao, Analysis of turbulent

flow patterns of soil water under field conditions using Burgers’ equation and

porous suction-cup samplers, Aust. J. Soil Res. 42 (1) (2004) 9–16.

[12] N.J. Zabusky, M.D. Kruskal, Interaction of solitons in a collisionless plasma and

the recurrence of initial states, Phys. Rev. 15 (1965) 240–243.

[13] P.F. Zhao, M.Z. Qin, Multisymplectic geometry and multisymplectic Preissmann

scheme for the KdV equation, J. Phys. A 33 (18) (2000) 3613–3626.

[14] H. Brezis, F. Browder, Partial differential equations in the 20th century, Adv.

Math. 135 (1998) 76–144.

[15] P.C. Jain, D.N. Holla, Numerical solution of coupled Burgers 1 equations, Int. J.

Numer. Methods Eng. 12 (1978) 213–222.[16] F.W. Wubs, E.D. de Goede, An explicit–implicit method for a class of time-

dependent partial differential equations, Appl. Numer. Math. 9 (1992) 157–181.

[17] C.A.J. Fletcher, Generating exact solutions of the two-dimensional Burgers’

equation, Int. J. Numer. Methods Fluids 3 (1983) 213–216.

[18] M.A. Abdou, A.A. Soliman, Variational iteration method for solving Burgers and

coupled Burgers equations, J. Comput. Appl. Math. 181 (2) (2005) 245–251.

[19] M.M. Rashidi, G. Domairry, S. Dinarvand, Approximate solutions for the Burg-

ers’ and regularized long wave equations by means of the homotopy analysis

method, Communications in Nonlinear Science and Numerical Simulation 14

(2009) 708–717.

[20] D.Q. Kern, D.A. Kraus, Extended Surface Heat Transfer, McGraw-Hill, New York,

1972.

[21] A.A. Aziz, E. Hug, Perturbation solution for convecting fin with variable thermal

conductivity, J. Heat Transfer 97 (1995) 300–310.

[22] G. Domairry, M. Fazeli, Homotopy analysis method to determine the fin ef-

ficiency of convective straight fins with temperature-dependent thermal con-

ductivity, Communications in Nonlinear Science and Numerical Simulation 14(2009) 489–499.

[23] C.K. Chen, S.H. Ho, Solving partial differential equations by two-dimensional

differential transform method, Appl. Math. Comput. 106 (1999) 171–179.

[24] M.J. Jang, C.L. Chen, Y.C. Liu, Two-dimensional differential transform for partial

differential equations, Appl. Math. Comput. 121 (2001) 261–270.

[25] A.H. Hassan, Different applications for the differential transformation in the

differential equations, Appl. Math. Comput. 129 (2002) 183–201.

[26] F. Ayaz, On two-dimensional differential transform method, Appl. Math. Com-

put. 143 (2003) 361–374.

[27] F. Ayaz, Solution of the system of differential equations by differential trans-

form method, Appl. Math. Comput. 147 (2004) 547–567.

[28] A. Kurnaz, G. Oturnaz, M.E. Kiris, n-Dimensional differential transformation

method for solving linear and nonlinear PDE’s, Int. J. Comput. Math. 82 (2005)

369–380.

[29] A.H. Hassan, Comparison differential transform technique with Adomian de-

composition method for linear and nonlinear initial value problems, Chaos

Solitons & Fractals 36 (2008) 53–65.[30] F. Kangalgil, F. Ayaz, Solitary wave solutions for the KdV and mKdV

equations by differential transform method, Chaos Solitons & Fractals,

doi:10.1016/j.chaos.2008.02.009.

[31] E. Hopf, The partial differential equation ut + uux = uxx, Commun. Pure. Appl.

Math. 3 (1950) 201–230.

[32] P.G. Drazin, R.S. Johnson, Soliton: an Introduction, Cambridge University Press,

Cambridge, 1989.

[33] J.H. He, Homotopy perturbation technique, Comput. Meth. Appl. Mech.

Eng. 178 (3/4) (1999) 257–262.