Advances in Numerical Analysis

Volume 2015 (2015), Article ID 367056, 8 pages

http://dx.doi.org/10.1155/2015/367056

## The Exponential Cubic B-Spline Algorithm for Korteweg-de Vries Equation

Department of Mathematics-Computer, Faculty of Science and Art, Eskişehir Osmangazi University, 26480 Eskişehir, Turkey

Received 16 September 2014; Revised 5 January 2015; Accepted 18 January 2015

Academic Editor: Yinnian He

Copyright © 2015 Ozlem Ersoy and Idris Dag. 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 exponential cubic B-spline algorithm is presented to find the numerical solutions of the Korteweg-de Vries (KdV) equation. The problem is reduced to a system of algebraic equations, which is solved by using a variant of Thomas algorithm. Numerical experiments are carried out to demonstrate the efficiency of the suggested algorithm.

#### 1. Introduction

The splines consist of piecewise functions defined on the distributed knots on problem domain and have certain continuity inside problem subdomain and at the knots. Until now, some types of splines have been developed and especially polynomial splines. The exponential splines are defined as more general splines by McCartin [1–3]. The basis of the exponential splines known as the exponential B-splines is also given in the studies of McCartin. Existence of the free parameter in the exponential B-splines yields the different shapes of the splines functions. He has also showed a reliable algorithm by using the exponential spline functions to solve the hyperbolic conservation laws, McCartin and Jameson [4]. However, McCartin stated that application of the exponential spline/exponential B-spline functions has been neglected in the numerical analysis. So, use of the exponential spline in the numerical methods for finding solutions of the differential equations is not common and few papers exist in the literature. McCartin has shown that the exponential splines admit a basis known as the exponential B-splines. These B-splines have been started using to form approximates functions recently which are adapted to set up the numerical methods to find solutions of the differential equations recently. An application of the simple exponential splines is considered for setting up the collocation method to solve the numerical solution of singular perturbation problem [5]. Cardinal exponential B-splines are applied in solving singularly perturbed boundary problems [6]. A variant of B-spline exponential collocation method was also built up for computing numerical solutions of the singularly perturbed boundary value problem [7]. Very recently, the exponential B-spline collocation method has been applied to obtain the solutions of the one-dimensional linear convection-diffusion equation [8].

Types of spline functions are utilized to form approximate solutions for Korteweg-de Vries equation (KdVE). The standard Galerkin formulation using the smooth splines on uniform mesh is set up for 1-periodic solutions of KdVE by Baker and his coauthors [9]. The Galerkin finite element method together with the cubic B-splines is used to solve the KdVE in the paper [10]. The quadratic B-spline Galerkin method is built up to find solutions of the KdVE [11]. A collocation solution of the Korteweg-de Vries equation using septic B-splines is proposed by Soliman [12]. A variant of the Galerkin finite element method is designed for solving the KdVE by Aksan and Özdeş [13]. The collocation method using quintic B-splines is developed to solve the KdVE [14]. A numerical method is developed for the KdVE by using splitting finite difference technique and quintic B-spline functions [15]. The spline finite element method using quadratic polynomial spline for the numerical solution of the KdVE is given by G. Micula and M. Micula [16]. A cubic B-spline Taylor-Galerkin method is developed to find numerical solution of the KdVE by Canıvar et al. in [17]. A study based on cubic B-spline finite element method for the solution of the KdVE is suggested by Kapoor et al. [18]. A Bubnov-Galerkin finite element method with quintic B-spline functions taken as element shape and weight functions is presented for the solution of the KdVE [19]. The paper deals with the numerical solution of the KdVE using quartic B-splines Galerkin method as both shape and weight functions over the finite intervals [20]. A blended spline quasi-interpolation scheme is employed to solve the one-dimensional nonlinear KdVE [21]. A multilevel quartic spline quasi-interpolation scheme is fulfilled to exhibit a large number of physical phenomena for KdVE [22].

The aim of the present paper is to develop an approximate solution of KdVE by collocation method. In Section 2, the exponential B-spline collocation algorithm is defined for the KdVE. In Section 3, the three numerical experiments are constructed to demonstrate the efficiency of the proposed method and the results are documented in tables and graphs are depicted.

We will solve the KdVE: where , are positive parameters and the subscripts and denote differentiation. The boundary conditions will be chosen as

KdVE is prototypical example of exactly solvable mathematical model of waves on shallow water surface. It arises for evolution, interaction of waves, and generation in physics. Due to the term , (1) is called the evolution equation, the nonlinear term causes the steepness of the wave, and the dispersive term defines the spreading of the wave. It is known that the effect of the steepness and spreading results in soliton solutions for the KdVE.

#### 2. Exponential B-Spline Collocation Method

The region is partitioned into equal subintervals by points , . On these points together with additional points , outside the domain, the exponential B-splines, , can be defined as where

forms a basis for the exponential spline space on the interval . On the four consecutive subintervals, an exponential B-spline is defined and it is second-order continuously differentiable functions.

In Table 1, the values of , , and at the points , which can be obtained from (3) are listed where denotes differentiation with respect to space variable .