- About this Journal ·
- Abstracting and Indexing ·
- Aims and Scope ·
- Annual Issues ·
- Article Processing Charges ·
- Articles in Press ·
- Author Guidelines ·
- Bibliographic Information ·
- Citations to this Journal ·
- Contact Information ·
- Editorial Board ·
- Editorial Workflow ·
- Free eTOC Alerts ·
- Publication Ethics ·
- Reviewers Acknowledgment ·
- Submit a Manuscript ·
- Subscription Information ·
- Table of Contents

Journal of Applied Mathematics

Volume 2012 (2012), Article ID 878349, 13 pages

http://dx.doi.org/10.1155/2012/878349

## Approximate Analytic Solution for the KdV and Burger Equations with the Homotopy Analysis Method

^{1}Department of Mathematical Sciences, Faculty of Science, Universiti Teknologi Malaysia, Johor, 81310 Johor Bahru, Malaysia^{2}Department of Mathematics, Faculty of Science, University of Kordofan, North Kordofan State, Elobeid 51111, Sudan^{3}Ibnu Sina Institute for Fundamental Science Studies, Universiti Teknologi Malaysia, Johor, 81310 Johor Bahru, Malaysia^{4}Department of Computer Science and Information System, Universiti Teknologi Malaysia, Johor, 81310 Johor Bahru, Malaysia

Received 11 June 2012; Accepted 25 July 2012

Academic Editor: Saeid Abbasbandy

Copyright © 2012 Mojtaba Nazari et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### Abstract

The homotopy analysis method (HAM) is applied to obtain the approximate analytic solution of the Korteweg-de Vries (KdV) and Burgers equations. The homotopy analysis method (HAM) is an analytic technique which provides us with a new way to obtain series solutions of such nonlinear problems. HAM contains the auxiliary parameter , which provides us with a straightforward way to adjust and control the convergence region of the series solution. The resulted HAM solution at 8th-order and 14th-order approximation is then compared with that of the exact soliton solutions of KdV and Burgers equations, respectively, and shown to be in excellent agreement.

#### 1. Introduction

It is difficult to solve nonlinear problems, especially by analytic technique. The homotopy analysis method (HAM) [1, 2] is an analytic technique for nonlinear problems, which was first introduced by Liao in 1992. This method has been successfully applied to many nonlinear problems in engineering and science, such as the magnetohydrodynamics flows of non-Newtonian fluids over a stretching sheet [3], boundary layer flows over an impermeable stretched plate [4], nonlinear model of combined convective and radiative cooling of a spherical body [5], exponentially decaying boundary layers [6], and unsteady boundary layer flows over a stretching flat plate [7]. Thus the validity, effectiveness, and flexibility of the HAM are verified via all of these successful applications. Also, many types of nonlinear problems were solved with HAM by others [8–22].

The Korteweg-de Vries equation (KdV equation) describes the theory of water wave in shallow channels, such as canal. It is an important mathematical model in nonlinear wave's theory and nonlinear optics. The same examples are widely used in solid-state physics, fluid physics, plasma physics, and quantum field theory.

The Burgers equation is a fundamental partial differential equation from fluid mechanics. It occurs in various areas of applied mathematics, such as modeling of gas dynamics and traffic flow. The first steady-state solution of Burgers equation was given by Bateman [23] in 1915. Although, the equation gets its name from the immense research of Burgers [24] beginning in 1939. The study of the general properties of the Burgers equation can be used as a model for any nonlinear wave diffusion problem subject to destruction [25]. Depending on the problem being modeled, this destruction may result from elasticity, gas dynamics, heat conduction, chemical reaction, or other resource.

In this paper, we employ the homotopy analysis method to obtain the solutions of the Korteweg-de Vries (KdV) and Burgers equations so as to provide us a new analytic approach for nonlinear problems.

#### 2. Basic Ideas of Homotopy Analysis Method (HAM)

Consider a nonlinear equation in a general form:
where is a nonlinear operator, is unknown function. Let denote an initial guess of the exact solution , an auxiliary parameter an auxiliary function, and an auxiliary linear operator, as an embedding parameter by means of homotopy analysis method, we construct the so-called *zeroth-order deformation* equation
It is very significant that one has great freedom to choose auxiliary objects in HAM. Clearly, when it holds that
respectively. Then as long as increase from 0 to 1, the solution varies from initial guess to the exact solution .

Liao [2] by Taylor theorem expanded in a power series of as follow: where

The convergence of the series (2.4) depends upon the auxiliary parameter , auxiliary function , initial guess , and auxiliary linear operator . If they were chosen properly, the series (2.4) is convergence at one has
According to definition (2.5), the governing equation can be inferred from the *zeroth-order deformation* equation (2.2). Define the vector

Differentiating the zero-order deformation equation (2.2) -times with respect to and dividing them by and finally setting we obtain the so-called -*order deformation* equation
where

Theorem 2.1 (Liao [2]). *As long as the series (2.6) is convergent, it is convergent to exact solution of (2.1).**Note that homotopy analysis method contains the auxiliary parameter , which provide us with that control and adjustment of the convergence of the series solution (2.6).*

#### 3. Exact Solution

The Korteweg-de Vries equation (KdV equation) describes the theory of water wave in shallow channels, such as canal. It is a nonlinear equation which governed by subject to We will suppose that the solution with its derivative, tends to zero [26, 27] when .

In 2001, Wazwaz [28] provided an exact solution or equivalently The Burgers equation is describe by subject to The exact solution of this equation is [29]

#### 4. HAM Solution

##### 4.1. The KdV Equation

For HAM solution of KdV equation we choose as the initial guess and as the auxiliary linear operator satisfying where is a constant.

We consider auxiliary function
*zeroth-order deformation problem**th-order deformation problem*

We can use software Mathematica for solving the set of linear equation (4.6) with condition (4.7). It is found that the solution in a series form is given by

The analytical solution given by (4.8) contains the auxiliary parameter , which influences the convergence region and rate of approximation for the HAM solution. In Figure 1, the -curves are plotted for when at 8th-order approximation.

As pointed out by Liao [2], the valid region of is a horizontal line segment. It is clear that the valid region for this case is . According to Theorem 2.1, the solution series (4.8) must be exact solution, as long as it is convergent. In this case, for and , the exact solution and HAM solution are the same, as shown in Figure 2. The obtained numerical results are summarized in Table 1.

In Figure 3, we study the diagrams of the results obtained by HAM for , and in comparison with the exact solution (3.1); we can see the best value for in this case is .

##### 4.2. The Burgers Equation

In this section, for HAM solution of the Burgers equation we choose as the initial guess and as the auxiliary linear operator satisfying where is a constant.

We consider auxiliary function
*zeroth-order deformation problem**th-order deformation problem*

We can use software Mathematica for solving the set of linear equation (4.14) with condition (4.15). It is found that the solution in a series form is given by

The analytical solution given by (4.16) contains the auxiliary parameter , which influences the convergence region and the rate of approximation for the HAM solution. In Figure 4, the -curve is plotted for , when at 14th-order approximation.

It is clear that the valid region for this case is . According to Theorem 2.1, the solution series (4.16) must be exact solution, as long as it is convergent. In this case, for and , the exact solution and HAM solution are the same, as shown in Figure 5. The obtained numerical results are summarized in Table 2.

In Figure 6, we study the diagrams of the results obtained by HAM for and in comparison with the exact solution (3.5); we can see the best value for in this case is .

#### 5. Conclusion

In this paper, the homotopy analysis method (HAM) [2] is applied to obtain the solitary solution of the KdV and Burger equations. HAM provides us with a convenient way to control the convergence of approximation series, which is a fundamental qualitative difference in analysis between HAM and other methods. So, these examples show the flexibility and potential of the homotopy analysis method for complicated nonlinear problems in engineering.

#### Acknowledgments

This research is partially funded by MOHE FRGS Vot no. 78675 and UTM RUG Vot no. PY/2011/02418. The authors wish to thank the anonymous reviewers whose comments led to some improvement to the presentation of the results.

#### References

- S. J. Liao,
*The proposed homotopy analysis technique for the solution of nonlinear problems [Ph.D. thesis]*, Shanghai Jiao University, 1992. View at Zentralblatt MATH - S. J. Liao, Ed.,
*Beyond Perturbation: Introduction to the Homotopy Analysis Method Boca Raton*, Chapman & Hall, Boca Raton, Fla, USA, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. J. Liao, “On the analytic solution of magnetohydrodynamic flows of non-Newtonian fluids over a stretching sheet,”
*Journal of Fluid Mechanics*, vol. 488, pp. 189–212, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. J. Liao, “A new branch of solutions of boundary-layer flows over an impermeable stretched plate,”
*International Journal of Heat and Mass Transfer*, vol. 48, no. 12, pp. 2529–2539, 2005. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus - S. J. Liao, J. Su, and A. T. Chwang, “Series solutions for a nonlinear model of combined convective and radiative cooling of a spherical body,”
*International Journal of Heat and Mass Transfer*, vol. 49, no. 15-16, pp. 2437–2445, 2006. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus - S. J. Liao and E. Magyari, “Exponentially decaying boundary layers as limiting cases of families of algebraically decaying ones,”
*Zeitschrift für Angewandte Mathematik und Physik*, vol. 57, no. 5, pp. 777–792, 2006. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. J. Liao, “Series solutions of unsteady boundary-layer flows over a stretching flat plate,”
*Studies in Applied Mathematics*, vol. 117, no. 3, pp. 239–263, 2006. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. Abbasbandy, “The application of homotopy analysis method to nonlinear equations arising in heat transfer,”
*Physics Letters A*, vol. 360, no. 1, pp. 109–113, 2006. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. Abbasbandy, “The application of homotopy analysis method to solve a generalized Hirota-Satsuma coupled KdV equation,”
*Physics Letters A*, vol. 361, no. 6, pp. 478–483, 2007. View at Publisher · View at Google Scholar · View at Scopus - S. Abbasbandy, “Homotopy analysis method for heat radiation equations,”
*International Communications in Heat and Mass Transfer*, vol. 34, no. 3, pp. 380–387, 2007. View at Publisher · View at Google Scholar · View at Scopus - M. Ayub, A. Rasheed, and T. Hayat, “Exact flow of a third grade fluid past a porous plate using homotopy analysis method,”
*International Journal of Engineering Science*, vol. 41, no. 18, pp. 2091–2103, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - T. Hayat and M. Khan, “Homotopy solutions for a generalized second-grade fluid past a porous plate,”
*Nonlinear Dynamics*, vol. 42, no. 4, pp. 395–405, 2005. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - T. Hayat, M. Khan, and M. Ayub, “On non-linear flows with slip boundary condition,”
*Zeitschrift für Angewandte Mathematik und Physik*, vol. 56, no. 6, pp. 1012–1029, 2005. View at Publisher · View at Google Scholar - S. Asghar, M. Mudassar Gulzar, and T. Hayat, “Rotating flow of a third grade fluid by homotopy analysis method,”
*Applied Mathematics and Computation*, vol. 165, no. 1, pp. 213–221, 2005. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - M. Sajid, T. Hayat, and S. Asghar, “On the analytic solution of the steady flow of a fourth grade fluid,”
*Physics Letters A*, vol. 355, no. 1, pp. 18–26, 2006. View at Publisher · View at Google Scholar · View at Scopus - Y. Tan and S. Abbasbandy, “Homotopy analysis method for quadratic Riccati differential equation,”
*Communications in Nonlinear Science and Numerical Simulation*, vol. 13, no. 3, pp. 539–546, 2008. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus - S. Abbasbandy and T. Hayat, “Solution of the MHD Falkner-Skan flow by homotopy analysis method,”
*Communications in Nonlinear Science and Numerical Simulation*, vol. 14, no. 9-10, pp. 3591–3598, 2009. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - C. Wang, Y. Y. Wu, and W. Wu, “Solving the nonlinear periodic wave problems with the Homotopy Analysis Method,”
*Wave Motion*, vol. 41, no. 4, pp. 329–337, 2005. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at Scopus - S. Abbasbandy and A. Shirzadi, “A new application of the homotopy analysis method: solving the Sturm-Liouville problems,”
*Communications in Nonlinear Science and Numerical Simulation*, vol. 16, no. 1, pp. 112–126, 2011. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. Abbasbandy and A. Shirzadi, “Homotopy analysis method for multiple solutions of the fractional Sturm-Liouville problems,”
*Numerical Algorithms*, vol. 54, no. 4, pp. 521–532, 2010. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - S. Abbasbandy and A. Shirzadi, “Homotopy analysis method for a nonlinear chemistry problem,”
*Studies in Nonlinear Sciences*, vol. 1, no. 4, pp. 127–132, 2010. View at Google Scholar - S. Abbasbandy and A. Shirzadi, “The series solution of problems in the calculus of variations via the homotopy analysis method,”
*Zeitschrift fur Naturforschung*, vol. 64, no. 1-2, pp. 30–36, 2009. View at Google Scholar · View at Scopus - H. Bateman, “Some recent researches on the motion of fluids,”
*Monthly Weather Review*, vol. 43, pp. 163–170, 1915. View at Publisher · View at Google Scholar - J. M. Burgers,
*Mathematical Examples Illustrating Relations Occurring in the Theory of Turbulent Fluid Motion*, vol. 17, Transitions of Royal Netherlands Academy of Arts and Sciences, Amsterdam, The Netherlands, 1939, Reprinted in F. T. M. Nieuwstadt and J. A. Steketee, Selected papers of J. M. Burgers, Kluwer Academic, Dordrecht, The Netherlands, pp. 281–334, 1995. - C. A. J. Fletcher, “Burgers' equation: a model for all reasons,” in
*Numerical Solutions of Partial Differential Equations*, North-Holland, Amsterdam, The Netherlands, 1982. View at Google Scholar · View at Zentralblatt MATH - M. J. Ablowitz and H. Segur, Eds.,
*Solitons and the Inverse Scattering Transform*, Society for Industrial and Applied Mathematics, Philadelphia, Pa, USA, 1981. - M. J. Ablowitz and P. A. Clarkson, Eds.,
*Solitons, Nonlinear Evolution Equations and Inverse Scattering*, Cambridge University Press, New York, NY, USA, 1991. View at Publisher · View at Google Scholar - A. M. Wazwaz, “Construction of solitary wave solutions and rational solutions for the KdV equation by Adomian decomposition method,”
*Chaos, Solitons and Fractals*, vol. 12, no. 12, pp. 2283–2293, 2001. View at Publisher · View at Google Scholar · View at Zentralblatt MATH - P. G. Drazin and R. S. Jonson,
*Soliton: An Introduction*, Cambridge University Press, New York, NY, USA, 1993.