Abstract and Applied Analysis

Volume 2014 (2014), Article ID 295936, 14 pages

http://dx.doi.org/10.1155/2014/295936

## An Efficient Numerical Approach for Solving Nonlinear Coupled Hyperbolic Partial Differential Equations with Nonlocal Conditions

^{1}Department of Mathematics, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia^{2}Department of Mathematics, Faculty of Science, Beni-Suef University, Beni-Suef 62511, Egypt

Received 20 January 2014; Accepted 22 February 2014; Published 9 April 2014

Academic Editor: Dumitru Baleanu

Copyright © 2014 A. H. Bhrawy 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

One of the most important advantages of collocation method is the possibility of dealing with nonlinear partial differential equations (PDEs) as well as PDEs with variable coefficients. A numerical solution based on a Jacobi collocation method is extended to solve nonlinear coupled hyperbolic PDEs with variable coefficients subject to initial-boundary nonlocal conservation conditions. This approach, based on Jacobi polynomials and Gauss-Lobatto quadrature integration, reduces solving the nonlinear coupled hyperbolic PDEs with variable coefficients to a system of nonlinear ordinary differential equation which is far easier to solve. In fact, we deal with initial-boundary coupled hyperbolic PDEs with variable coefficients as well as initial-nonlocal conditions. Using triangular, soliton, and exponential-triangular solutions as exact solutions, the obtained results show that the proposed numerical algorithm is efficient and very accurate.

#### 1. Introduction

For several decades, numerical methods have been developed to obtain more accurate solutions of differential and integral equations. Spectral method [1–9] is one of the family of weighted residual numerical methods for solving various problems, including variable coefficient and nonlinear differential equations [10, 11], integral equations [12, 13], integrodifferential equations [14, 15], fractional orders differential equations [16–19], and function approximation and variational problems [20]. The collocation method [21–28] can be classified as a special type of spectral methods. In the last few years, the collocation method has been introduced as a powerful approximation method for numerical solutions of all kinds of initial-boundary value problems.

Exact solutions for initial value problem for some nonconservative hyperbolic systems are presented in [29], while the analytical study of variable coefficient mixed hyperbolic partial differential problems is discussed in [30]. The solitary and periodic wave solutions have been studied for some kinds of hyperbolic Klein-Gordon equations in [31, 32]. Other numerical methods based on the boundary integral equation [33] and numerical integration techniques [34] are used to numerically solve different types of hyperbolic partial differential problems. In [35, 36], finite difference scheme is considered to numerically solve hyperbolic equations. Pseudospectral methods are used in [37–40] to solve Klein-Gordon equations. In [41], Dehghan and Shokri used the radial basis functions to solve a two-dimensional Sine-Gordon equation; moreover in [42] they developed numerical scheme to solve the one-dimensional nonlinear Klein-Gordon equation with quadratic and cubic nonlinearity using collocation points and approximating the solution using Thin Plate Splines and RBFs.

There are no results on Jacobi-Gauss-Lobatto collocation (J-GL-C) method for solving nonlinear coupled hyperbolic PDEs with variable coefficients subject to initial-boundary and nonlocal conditions. Therefore, the objective of this work is to present this method to numerically solve four nonlinear coupled hyperbolic PDEs with variable coefficients. By using collocation method, exponential convergence for the spatial variables can be achieved to approximate the solution of PDE. The computerized mathematical algorithm is the main key to apply this method for solving the problem. Moreover, the nonlocal conservation conditions are efficiently treated by Jacobi-Gauss-Lobatto quadrature rule at nodes to obtain a system of ODEs in time and then proper initial value software can be applied to solve this system of ODEs. Several illustrative problems with various kinds of exact solutions such as triangular, soliton, and exponential-triangular solutions are presented for demonstrating the high accuracy of this scheme. Moreover, with the freedom of selecting the Jacobi indexes and , the scheme can be calibrated for a wide variety of problems. Finally, the accuracy of the proposed method is demonstrated by solving some test nonlinear problems.

A brief outline of this paper is as follows. We present some properties of Jacobi polynomials in the next section. The third section is divided into two subsections: the first one deals with coupled nonlinear hyperbolic PDE with initial-boundary conditions. The numerical treatment of solve initial-nonlocal conservation conditions is developed in Section 3.2. In Section 4 the proposed method is applied to four different test problems to show the accuracy of our method. In the last section, we present some observations and conclusions.

#### 2. Jacobi Polynomials

Some basic properties of Jacobi polynomials have been recalled in this section. A basic property of the Jacobi polynomials is that they are the eigenfunctions to a singular Sturm-Liouville problem: We recall that the Jacobi polynomials satisfy the following recurrence relation: where Beside the following relations Moreover, the th derivative of can be obtained from Let ; then we define the weighted space as usual. The inner product and the norm of with respect to the weight function are defined as follows: The set of Jacobi polynomials forms a complete -orthogonal system, and

#### 3. The Problem and the Numerical Algorithm

In this section, we approximate the solution of coupled nonlinear hyperbolic types equations with two different kinds of boundary conditions for space variable by using the Jacobi collocation method.

##### 3.1. Initial-Boundary Conditions

In what follows, we propose an efficient numerical algorithm to solve the coupled nonlinear hyperbolic types equations in the following form: related to the initial conditions, and the boundary conditions, Starting with the transformations . Problem (8)–(10) will be a new problem in the spatial variable . This transformation enable us to use the Jacobi collocation method on , subject to a new set of initial and boundary conditions,

Now, we are interested in using the J-GL-C method to transform the previous coupled PDEs into system of ODEs. In order to do this, we approximate the spatial variable using J-GL-C method at some nodal points. The node points are the set of points in a specified domain where the dependent variable values are approximated. In general, the choice of the location of the node points is optional, but taking the roots of the Jacobi orthogonal polynomials referred to as Jacobi collocation points gives particularly accurate solutions for the spectral methods. Now, we outline the main step of the J-GL-C method for solving couples hyperbolic problem. Let us expand the dependent variable in a Jacobi series, And, in virtue of (6)-(7), we evaluate and by The Jacobi-Gauss-Lobatto quadrature has been used to evaluate the previous integrals accurately. For any , we have that For any positive integer , stands for the set of polynomials of degree at most , () and () are used as the nodes and the corresponding Christoffel numbers in the interval , respectively. Thanks to (6), the coefficients in terms of the solution at the collocation points can be approximated by Due to (17), the approximate solution can be written as Furthermore, if we differentiate (18) once and evaluate it at the first Jacobi-Gauss-Lobatto collocation points, it is easy to compute the first spatial partial derivative of the numerical solution in terms of the values at these collocation points as where Accordingly, one can obtain the second spatial partial derivative as where In the proposed J-GL-C method the residual of (11) is set to zero at of Jacobi-Gauss-Lobatto points; moreover, the boundary conditions (13) will be enforced at the two collocation points and . Therefore, the approximation of (11)–(13) is where This approach provides a system of second order ODEs in the expansion coefficients , , with the following initial conditions: or in matrix notation as with where The system of second order (27)-(28) can be solved by using diagonally implicit Runge-Kutta-Nyström (DIRKN).

##### 3.2. Initial-Nonlocal Conservation Conditions

Here, we will implement the J-GL-C algorithm for the coupled nonlinear hyperbolic type equations with nonlocal conditions: subject to the initial conditions, and the boundary conditions, while the other two boundary conditions have the nonlocal conservation form Again, we used the change of variables , to reduce problem (30)–(33) into related to the new initial conditions, the boundary conditions, and the nonlocal conservation conditions, The problem now is how to deal with the nonlocal conditions (37). For this purpose, let us introduce a collocation treatment for the integral conservation conditions (37) as The above equations may be rearranged as or briefly where Consequently, and are expressed as the following expansion of and , : Based on the information included in this subsection and the recent one, we obtain the following system of ODEs: with the following initial conditions: where , , , and are given in (36) and (42).

#### 4. Test Problems

We test the numerical accuracy of the proposed method by introducing four test problems with different types of exact solutions.

##### 4.1. Triangular Solution

As a first example, we consider the coupled nonlinear hyperbolic equation (8) with the following functions: subject to The exact solutions of this problem are The absolute errors in the given tables are where and are the exact and approximate solutions at the point , respectively. Moreover, the maximum absolute error is given by The root mean square (RMS) and errors may be given by Maximum absolute, root mean square, and errors of (45) are introduced in Table 1 using J-GL-C method with three different choices of , and in the interval . The approximate solutions and of problem (45) have been plotted in Figures 1 and 2, with values of parameters listed in their captions. Moreover, we plot the curves of approximate and exact solutions of at different values of and in Figures 3 and 4. Again, the curves of approximate and exact solutions of at different values of and are displayed in Figures 5 and 6.

##### 4.2. Soliton Solution

Secondly, consider the coupled nonlinear hyperbolic equation (8) with the following functions: subject to The exact solutions are Table 2 shows the accurate results for maximum absolute, root mean square, and errors of (51) for various choices of , and in the interval . Figures 7 and 8 show that the absolute errors and are very small with values of parameters listed in their captions. We also plot the curves of approximate and exact solutions of at different values of and in Figures 9 and 10. Moreover, in Figures 11 and 12, the approximate and exact solutions of are plotted at different values of and .

##### 4.3. Exponential-Triangular Solution

In the third example, consider the coupled nonlinear hyperbolic equations (8)-(9) with the following functions: the initial-boundary conditions (9) and (10) may be given by The exact solutions of this problem are More accurate results for maximum absolute, root mean square, and errors of (55) are given in Table 3, for different choices of Jacobi parameters; even we use limited values of . The approximate solutions and of problem (55) are plotted in Figures 13 and 14 with values of parameters listed in their captions. In addition, Figures 15 and 16 present the approximate and exact solutions of ; moreover, the corresponding figures for at parameters listed in their captions are displayed in Figures 17 and 18.

##### 4.4. Triangular Solution

In the last example, consider the coupled nonlinear hyperbolic equation (30) with the following functions: related to the initial conditions (31), and the boundary conditions (32), while the nonlocal conservation conditions are (33) The exact solutions of (30) are Maximum absolute, root mean square, and errors of (57) are introduced in Table 4 using J-GL-C method with various choices of , and in the interval . From numerical results of this table, it can be concluded that the numerical solutions for problems with nonlocal conservation conditions are in good agreement with the exact solutions.

#### 5. Conclusion

For boundary and nonlocal conditions, we have proposed an efficient and accurate numerical algorithm based on Jacobi-Gauss-Lobatto spectral method to get high accurate solutions for nonlinear coupled hyperbolic equations. The method is based upon reducing the mentioned problem into a system of second order ODEs in the expansion coefficient of the solution. The use of the Jacobi-Gauss-Lobatto points as collocation nodes saves the spectral convergence for the spatial variable in the approximate solution. Numerical examples were also provided to illustrate the effectiveness of the derived algorithm. The numerical experiments show that the Jacobi collocation approximation is very accurate with a limited number of collocation nodes.

#### Conflict of Interests

The authors declare that there is no conflict of interests regarding the publication of this paper.

#### Acknowledgments

This paper was funded by the Deanship of Scientific Research DSR, King Abdulaziz University, Jeddah. The authors, therefore, acknowledge with thanks DSR technical and financial support.

#### References

- K. Krastev and M. Schäfer, “A multigrid pseudo-spectral method for incompressible Navier-Stokes flows,”
*Comptes Rendus—Mecanique*, vol. 333, no. 1, pp. 59–64, 2005. View at Publisher · View at Google Scholar · View at Scopus - E. H. Doha, A. H. Bhrawy, D. Baleanu, and R. M. Hafez, “A new Jacobi rational–Gauss collocation method for numerical solution of generalized pantograph equations,”
*Applied Numerical Mathematics*, vol. 77, pp. 43–54, 2014. View at Publisher · View at Google Scholar · View at MathSciNet - E. H. Doha, A. H. Bhrawy, M. A. Abdelkawy, and R. A. Van Gorder, “Jacobi-Gauss-Lobatto collocation method for the numerical solution of $1+1$ nonlinear Schrödinger equations,”
*Journal of Computational Physics*, vol. 261, pp. 244–255, 2014. View at Publisher · View at Google Scholar · View at MathSciNet - A. Saadatmandi, “Bernstein operational matrix of fractional derivatives and its applications,”
*Applied Mathematical Modelling. Simulation and Computation for Engineering and Environmental Systems*, vol. 38, no. 4, pp. 1365–1372, 2014. View at Publisher · View at Google Scholar · View at MathSciNet - E. H. Doha and A. H. Bhrawy, “An efficient direct solver for multidimensional elliptic Robin boundary value problems using a Legendre spectral-Galerkin method,”
*Computers & Mathematics with Applications*, vol. 64, no. 4, pp. 558–571, 2012. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - W. M. Abd-Elhameed, E. H. Doha, and Y. H. Youssri, “New wavelets collocation method for solving second-order multipoint boundary value problems using Chebyshev polynomials of third and fourth kinds,”
*Abstract and Applied Analysis*, vol. 2013, Article ID 542839, 9 pages, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - W. M. Abd-Elhameed, E. H. Doha, and M. A. Bassuony, “Two Legendre-Dual-Petrov-Galerkin algorithms for solving the integrated forms of high odd-order boundary value problems,”
*The Scientific World Journal*, vol. 2013, Article ID 309264, 11 pages, 2013. View at Publisher · View at Google Scholar - D. Baleanu, A. H. Bhrawy, and T. M. Taha, “Two efficient generalized Laguerre spectral algorithms for fractional initial value problems,”
*Abstract and Applied Analysis*, vol. 2013, Article ID 546502, 10 pages, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - K. Schneider, S. Neffaa, and W. J. T. Bos, “A pseudo-spectral method with volume penalisation for magnetohydrodynamic turbulence in confined domains,”
*Computer Physics Communications*, vol. 182, no. 1, pp. 2–7, 2011. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - A. H. Bhrawy, “A Jacobi-Gauss-Lobatto collocation method for solving generalized Fitzhugh-Nagumo equation with time-dependent coefficients,”
*Applied Mathematics and Computation*, vol. 222, pp. 255–264, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - M. Dehghan and F. Fakhar-Izadi, “The spectral collocation method with three different bases for solving a nonlinear partial differential equation arising in modeling of nonlinear waves,”
*Mathematical and Computer Modelling*, vol. 53, no. 9-10, pp. 1865–1877, 2011. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - A. H. Bhrawy, E. Tohidi, and F. Soleymani, “A new Bernoulli matrix method for solving high-order linear and nonlinear Fredholm integro-differential equations with piecewise intervals,”
*Applied Mathematics and Computation*, vol. 219, no. 2, pp. 482–497, 2012. View at Publisher · View at Google Scholar · View at MathSciNet - K. Maleknejad, B. Basirat, and E. Hashemizadeh, “A Bernstein operational matrix approach for solving a system of high order linear Volterra-Fredholm integro-differential equations,”
*Mathematical and Computer Modelling*, vol. 55, no. 3-4, pp. 1363–1372, 2012. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - Y. Jiang and J. Ma, “Spectral collocation methods for Volterra-integro differential equations with noncompact kernels,”
*Journal of Computational and Applied Mathematics*, vol. 244, pp. 115–124, 2013. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - S. Yüzbaşı, M. Sezer, and B. Kemancı, “Numerical solutions of integro-differential equations and application of a population model with an improved Legendre method,”
*Applied Mathematical Modelling*, vol. 37, no. 4, pp. 2086–2101, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - A. H. Bhrawy and M. A. Alghamdi, “A shifted Jacobi-Gauss-Lobatto collocation method for solving nonlinear factional Langevin equation involving two fractional orders in different intervals,”
*Boundary Value Problems*, vol. 2012, article 62, 2012. View at Publisher · View at Google Scholar - M. H. Heydari, M. R. Hooshmandasl, C. Cattani, and M. Li, “Legendre wavelets method for solving fractional population growth model in a closed system,”
*Mathematical Problems in Engineering*, vol. 2013, Article ID 161030, 8 pages, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - E. H. Doha, A. H. Bhrawy, D. Baleanu, and S. S. Ezz-Eldien, “On shifted Jacobi spectral approximations for solving fractional differential equations,”
*Applied Mathematics and Computation*, vol. 219, no. 15, pp. 8042–8056, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - A. H. Bhrawy and A. S. Alofi, “The operational matrix of fractional integration for shifted Chebyshev polynomials,”
*Applied Mathematics Letters*, vol. 26, no. 1, pp. 25–31, 2013. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - C. Canuto, M. Y. Hussaini, A. Quarteroni, and T. A. Zang,
*Spectral Methods: Fundamentals in Single Domains*, Scientific Computation, Springer, New York, NY, USA, 2006. View at MathSciNet - R. C. Mittal and R. Bhatia, “Numerical solution of second order one dimensional hyperbolic telegraph equation by cubic B-spline collocation method,”
*Applied Mathematics and Computation*, vol. 220, pp. 496–506, 2013. View at Publisher · View at Google Scholar · View at MathSciNet - L. Yi and Z. Wang, “Legendre-Gauss-type spectral collocation algorithms for nonlinear ordinary/partial differential equations,”
*International Journal of Computer Mathematics*, 2013. View at Publisher · View at Google Scholar - L. Yi and Z. Wang, “Legendre spectral collocation method for second-order nonlinear ordinary/ partial differential equations,”
*Discrete and Continuous Dynamical Systems B*, vol. 19, pp. 299–322, 2014. View at Google Scholar - E. H. Doha, A. H. Bhrawy, R. M. Hafez, and M. A. Abdelkawy, “A Chebyshev-Gauss-Radau scheme for nonlinear hyperbolic system of first order,”
*Applied Mathematics & Information Sciences*, vol. 8, no. 2, pp. 535–544, 2014. View at Publisher · View at Google Scholar · View at MathSciNet - Y.-S. Sun and B.-W. Li, “Prediction of radiative heat transfer in 2D irregular geometries using the collocation spectral method based on body-fitted coordinates,”
*Journal of Quantitative Spectroscopy and Radiative Transfer*, vol. 113, pp. 2205–2212, 2012. View at Google Scholar - Z.-Q. Wang and B.-Y. Guo, “Legendre-Gauss-Radau collocation method for solving initial value problems of first order ordinary differential equations,”
*Journal of Scientific Computing*, vol. 52, no. 1, pp. 226–255, 2012. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - E. Tohidi, A. H. Bhrawy, and K. Erfani, “A collocation method based on Bernoulli operational matrix for numerical solution of generalized pantograph equation,”
*Applied Mathematical Modelling*, vol. 37, no. 6, pp. 4283–4294, 2013. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - M. Kamrani and S. M. Hosseini, “Spectral collocation method for stochastic Burgers equation driven by additive noise,”
*Mathematics and Computers in Simulation*, vol. 82, no. 9, pp. 1630–1644, 2012. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - K. T. Joseph and P. L. Sachdev, “Exact solutions for some non-conservative hyperbolic systems,”
*International Journal of Non-Linear Mechanics*, vol. 38, no. 9, pp. 1377–1386, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - M. J. Rodriguez-Alvarez, G. Rubio, and L. Jódar, “Exact solution of variable coefficient mixed hyperbolic partial differential problems,”
*Applied Mathematics Letters*, vol. 16, no. 3, pp. 309–312, 2003. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - Z.-Y. Zhang, J. Zhong, S. S. Dou, J. Liu, D. Peng, and T. Gao, “Abundant exact travelling wave solutions for the Klein-Gordon-Zakharov equations via the tanh-coth expansion method and Jacobi elliptic function expansion method,”
*Romanian Journal of Physics*, vol. 58, no. 7-8, pp. 749–765, 2013. View at Google Scholar · View at MathSciNet - Z.-Y. Zhang, J. Zhong, S. S. Dou, J. Liu, D. Peng, and T. Gao, “A new method to construct travelling wave solutions for the Klein-Gordon-Zakharov equations,”
*Romanian Journal of Physics*, vol. 58, no. 7-8, pp. 766–777, 2013. View at Google Scholar · View at MathSciNet - M. Dehghan and A. Ghesmati, “Solution of the second-order one-dimensional hyperbolic telegraph equation by using the dual reciprocity boundary integral equation (DRBIE) method,”
*Engineering Analysis with Boundary Elements*, vol. 34, no. 1, pp. 51–59, 2010. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - E. Ponsoda, L. Jódar, and S. Jerez, “Numerical solution with a priori error bounds of coupled time dependent hyperbolic systems,”
*Computers & Mathematics with Applications*, vol. 47, no. 2-3, pp. 233–246, 2004. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - M. A. M. Lynch, “Large amplitude instability in finite difference approximations to the Klein-Gordon equation,”
*Applied Numerical Mathematics*, vol. 31, no. 2, pp. 173–182, 1999. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - X. Cui, J.-Y. Yue, and G.-W. Yuan, “Nonlinear scheme with high accuracy for nonlinear coupled parabolic-hyperbolic system,”
*Journal of Computational and Applied Mathematics*, vol. 235, no. 12, pp. 3527–3540, 2011. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - E. H. Doha, A. H. Bhrawy, D. Baleanu, and M. A. Abdelkawy, “Numerical treatment of coupled nonlinear hyperbolic Klein-Gordon equations,”
*Romanian Journal of Physics*, vol. 59, no. 3-4, 2014. View at Google Scholar - E. H. Doha, A. H. Bhrawy, D. Baleanu, and M. A. Abdelkawy, “An accurate Legendre collocation scheme for coupled hyperbolic equations with variable coefficients,”
*Romanian Journal of Physics*. In press. - G. Ben-Yu, L. Xun, and L. Vázquez, “A Legendre spectral method for solving the nonlinear Klein-Gordon equation,”
*Mathematics Applied and Computation*, vol. 15, no. 1, pp. 19–36, 1996. View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - X. Li and B. Y. Guo, “A Legendre pseudospectral method for solving nonlinear Klein-Gordon equation,”
*Journal of Computational Mathematics*, vol. 15, no. 2, pp. 105–126, 1997. View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - M. Dehghan and A. Shokri, “A numerical method for solution of the two-dimensional sine-Gordon equation using the radial basis functions,”
*Mathematics and Computers in Simulation*, vol. 79, no. 3, pp. 700–715, 2008. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet - M. Dehghan and A. Shokri, “Numerical solution of the nonlinear Klein-Gordon equation using radial basis functions,”
*Journal of Computational and Applied Mathematics*, vol. 230, no. 2, pp. 400–410, 2009. View at Publisher · View at Google Scholar · View at Zentralblatt MATH · View at MathSciNet