<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE article  PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "http://dtd.nlm.nih.gov/publishing/3.0/journalpublishing3.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" dtd-version="3.0" xml:lang="en" article-type="research article"><front><journal-meta><journal-id journal-id-type="publisher-id">AM</journal-id><journal-title-group><journal-title>Applied Mathematics</journal-title></journal-title-group><issn pub-type="epub">2152-7385</issn><publisher><publisher-name>Scientific Research Publishing</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="doi">10.4236/am.2017.812128</article-id><article-id pub-id-type="publisher-id">AM-81217</article-id><article-categories><subj-group subj-group-type="heading"><subject>Articles</subject></subj-group><subj-group subj-group-type="Discipline-v2"><subject>Physics&amp;Mathematics</subject></subj-group></article-categories><title-group><article-title>
 
 
  Chelyshkov-Tau Approach for Solving Bagley-Torvik Equation
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Mohamed</surname><given-names>El- Gamel</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref><xref ref-type="corresp" rid="cor1"><sup>*</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Mahmoud</surname><given-names>Abd-El-Hady</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Magdy</surname><given-names>El-Azab</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib></contrib-group><aff id="aff1"><addr-line>Department of Mathematical Sciences, Faculty of Engineering, Mansoura University, Mansoura, Egypt</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>gamel_eg@yahoo.com(MEG)</email>;</corresp></author-notes><pub-date pub-type="epub"><day>04</day><month>12</month><year>2017</year></pub-date><volume>08</volume><issue>12</issue><fpage>1795</fpage><lpage>1807</lpage><history><date date-type="received"><day>26,</day>	<month>October</month>	<year>2017</year></date><date date-type="rev-recd"><day>18,</day>	<month>December</month>	<year>2017</year>	</date><date date-type="accepted"><day>21,</day>	<month>December</month>	<year>2017</year></date></history><permissions><copyright-statement>&#169; Copyright  2014 by authors and Scientific Research Publishing Inc. </copyright-statement><copyright-year>2014</copyright-year><license><license-p>This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/</license-p></license></permissions><abstract><p>
 
 
  
    There are few numerical techniques available to solve the Bagley-Torvik equation which occurs considerably frequently in various offshoots of applied mathematics and mechanics. In this paper, we show that Chelyshkov-tau method is a very effective tool in numerically solving this equation. To show the accuracy and the efficiency of the method, several problems are implemented and the comparisons are given with other methods existing in the recent literature. The results of numerical tests confirm that Chelyshkov-tau method is superior to other existing ones and is highly accurate. 
  
 
</p></abstract><kwd-group><kwd>Chelyshkov</kwd><kwd> Tau Method</kwd><kwd> Bagley-Torvik</kwd><kwd> Caputo Derivative</kwd><kwd> Residual Functions</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>Recently, the fractional derivative has attracted a lot of attentions due to widely applied in various fields of physics and engineering. Fractional derivative is an excellent tool to describe memory and genetic characteristics of various materials and processes. Many phenomena in various fields of science and engineering such as control, porous media, electrochemistry, viscoelasticity, electromagnetic, etc. can be described by Fractional differential Equation (FDE). The evolution of effective and perfectly appropriate method for numerically solving FDEs has received great attention over the past years.</p><p>In this paper, we develop a new approach called Chelyshkov-tau method for solving Bagley-Torvik equation of the form</p><p>A 2   u ″ ( x ) + A 1   u ( 3 / 2 ) ( x ) + A 0   u ( x ) = f ( x ) ,   x ∈ [ 0 , 1 ] (1)</p><p>subject to the boundary conditions</p><p>∑ j = 0 1       α i j   u ( j ) ( 0 ) +   β i j   u ( j ) ( 1 ) = γ i ,   i = 0 , 1 (2)</p><p>where A 2 ≠ 0 represents mass of the thin rigid plate immersed in a Newtonian fluid, A 1 is constant depending on area of the thin rigid, viscosity and density of fluid and A 0 represents stiffness of the spring. f ( x ) is a given function. u ( x ) represents motion of the rigid plate. The questions of existence and uniqueness of the solution to this initial value problem have been discussed in [<xref ref-type="bibr" rid="scirp.81217-ref1">1</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref2">2</xref>] , so there is no need to go into these matters here.</p><p>Several numerical and analytical methods of Equation (1) were considered by many authors, such as finite difference method [<xref ref-type="bibr" rid="scirp.81217-ref3">3</xref>] , collocation method based on M&#252;ntz polynomials [<xref ref-type="bibr" rid="scirp.81217-ref4">4</xref>] , Tau approximate [<xref ref-type="bibr" rid="scirp.81217-ref5">5</xref>] , Adomian decomposition method [<xref ref-type="bibr" rid="scirp.81217-ref6">6</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref7">7</xref>] , variational iteration method [<xref ref-type="bibr" rid="scirp.81217-ref8">8</xref>] , the generalized block pulse operational matrix [<xref ref-type="bibr" rid="scirp.81217-ref9">9</xref>] , homotopy perturbation method [<xref ref-type="bibr" rid="scirp.81217-ref10">10</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref11">11</xref>] , generalized differential transform method [<xref ref-type="bibr" rid="scirp.81217-ref12">12</xref>] , Legendre-collocation method [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] , Laplace transforms [<xref ref-type="bibr" rid="scirp.81217-ref14">14</xref>] , Fourier transforms [<xref ref-type="bibr" rid="scirp.81217-ref15">15</xref>] , eigenvector expansion [<xref ref-type="bibr" rid="scirp.81217-ref16">16</xref>] , fractional differential transform method [<xref ref-type="bibr" rid="scirp.81217-ref17">17</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref18">18</xref>] , the fractional iteration method [<xref ref-type="bibr" rid="scirp.81217-ref19">19</xref>] , power series method [<xref ref-type="bibr" rid="scirp.81217-ref20">20</xref>] , Bessel collocation method [<xref ref-type="bibr" rid="scirp.81217-ref21">21</xref>] , wavelet [<xref ref-type="bibr" rid="scirp.81217-ref22">22</xref>] and the Haar wavelet method [<xref ref-type="bibr" rid="scirp.81217-ref23">23</xref>] .</p><p>Orthogonal polynomials play an important role in mathematics as well as in applications in mathematical physics, engineering and computer science. Chelyshkov polynomials are the most recent set of orthogonal polynomials. Chelyshkov polynomials have become increasingly important in numerical analysis. The efficiency of the method has been officially established by many researchers [<xref ref-type="bibr" rid="scirp.81217-ref24">24</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref25">25</xref>] . With these backgrounds, we extend Chelyshkov-tau method for solving Bagley-Torvik equation of Equation (1).</p><p>The efficiency and accuracy of the numerical scheme is assessed on specific test problems. The numerical outcomes indicate that the method yields highly accurate results. The numerical solutions are compared with analytical and other existing numerical solutions in the literature.</p><p>The paper is organized as follows. Section 2 preliminarily provides some definitions which are crucial to the following discussion. In Section 3 we apply Chelyshkov-tau method for solving the model equation. In Section 4, we present numerical examples to exhibit the accuracy and the efficiency of the present method. where the numerical results presented in this paper are computed by Matlab programming. The conclusion is presented in the final section.</p></sec><sec id="s2"><title>2. Preliminaries</title><sec id="s2_1"><title>2.1. Basic Definitions of Fractional</title><p>In this section, we introduce the basic necessary definitions and primary facts of the fractional calculus theory which will be more used in this work [<xref ref-type="bibr" rid="scirp.81217-ref26">26</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref27">27</xref>] .</p><p>Definition 1. The Riemann-Liouville fractional integral operator J α of order α on a usual Lebesgue space L 1 [ a , b ] is given by</p><p>J α ψ ( t ) = 1 Γ ( α ) ∫ 0 t ( t − s ) α − 1 ψ ( s ) d s</p><p>Some characteristics of this operator are:</p><p>J 0 ψ ( t ) = ψ ( t ) ,     J α   J β ψ ( t ) = J α + β ψ ( t ) ,     J α   J β ψ ( t ) = J β   J α ψ ( t ) ,     ( α , β ≥ 0 ) J α ( t − s ) μ = Γ ( μ + 1 ) Γ ( α + μ + 1 ) ( t − s ) α + μ ,   ( μ &gt; − 1 )</p><p>The Riemann-Liouville fractional derivative operator D α is given by</p><p>D α ψ ( t ) = ( d d t ) m ( J m − α ψ (t))</p><p>where m is an integer, provided that m − 1 &lt; α ≤ m .</p><p>However, its derivative has Some drawbacks when we try to make a model for a real phenomenon using fractional differential equations. Therefore, we will provide a modified fractional differential operator D α proposed by by Caputo [<xref ref-type="bibr" rid="scirp.81217-ref28">28</xref>] .</p><p>Definition 2. The Caputo derivative definition is defined as</p><p>D α   ψ ( t ) = 1 Γ ( m − α )   ∫ 0 x   ( t − s ) m − α − 1   ψ ( m ) ( s ) d s   ,   m − 1 &lt; α ≤ m , m ∈ ℕ (3)</p><p>Hence, α &gt; 0 and m is the smallest integer greater than or equal to α . For the Caputo fractional derivative we have</p><p>D α c = 0 ,   ( c   is   constant ) , D α J α ψ ( t ) = ψ ( t ) , J α D α ψ ( t ) = ψ ( t ) − ∑ i = 0 m − 1     ψ ( i ) ( 0 + ) ( t − s ) i i ! , D α t β = { 0                                                       for   β &lt; ⌈ α ⌉ , Γ ( β + 1 ) Γ ( β + 1 − α )   t β − α ,         for       β ≥ ⌈ α ⌉ . (4)</p><p>It can be said when α ∈ ℕ , the Caputo differential operator matches with the integer-order differential operator.</p><p>For more details on fractional derivative definitions, theorems and its properties, you can see [<xref ref-type="bibr" rid="scirp.81217-ref26">26</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref27">27</xref>] .</p></sec><sec id="s2_2"><title>2.2. Some Properties of Chelyshkov Polynomials</title><p>We first review some important concepts and basics of the Chelyshkov function and conclude useful results that are important to this paper. Recently, these polynomials have established by Chelyshkov in [<xref ref-type="bibr" rid="scirp.81217-ref29">29</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref30">30</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref31">31</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref32">32</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref33">33</xref>] , which are orthogonal over the interval [ 0,1 ] , and are explicitly defined by</p><p>C N j ( x ) = ∑ i = 0 N − j   ( − 1 ) i   ( N − j i )   ( N + j + k + 1 N − j )   x N + k ,   j = 0 , 1 , ⋯ , N (5)</p><p>This gives the Rodrigues formula</p><p>C N j ( x ) = 1 ( N − j ) !   1 x j + 1   d N − j d x N − j   [ x N + j + 1   ( 1 − x ) N − j ] ,   j = 0 , 1 , ⋯ , N</p><p>and the orthogonality condition of Chelyshkov polynomials [<xref ref-type="bibr" rid="scirp.81217-ref32">32</xref>] is</p><p>∫ 0 1     C N j ( x ) C N k ( x ) d x = { 1 j + k + 1 ,       for     j = k ,     j , k = 0 , 1 , ⋯ , N , N + 1 0 ,                           for     j ≠ k . (6)</p><p>Also it follows from this relation that</p><p>∫ 0 1   C N j ( x ) d x = ∫ 0 1   x j d x = 1 j + 1</p><p>By using the Cauchy integral formula for derivative and the Rodrigues type representation, we can get the integral relation</p><p>C N j ( x ) = 1 2 π i 1 x j + 2 ∫ Ω 1 s &#175; N + j + 2   ( 1 − s ) N − j ( s − x − 1 ) N − j + 1 d s</p><p>such that the point s = x − 1 . lies in closed curve Ω 1 .</p><p>Chelyshkov polynomials C N j ( x ) provide a natural way to solve, expand, and interpret solutions. Actually, these polynomials can be expressed in terms of the Jacobi polynomials P k ( α , β ) by the following relation,</p><p>C N j ( x ) = x j P N − j ( 2 j , 1 ) ( 1 − 2 x ) ,   j = 0 , 1 , ⋯ , N</p><p>Let function u ( x ) , square integrable in [ 0,1 ] , can be expressed in terms of Chelyshkov polynomials as</p><p>u ( x ) ≅ u N ( x ) = ∑ j = 0 N     a j C N j ( x ) , (7)</p><p>where the coefficients a j are the unknown Chelyshkov coefficients and C N j , j = 0 , 1 , ⋯ , N are Chelyshkov orthogonal polynomials of the degree N such that N ≥ 2 . Also,</p><p>u ′ N ( x ) = ∑ j = 0 N     a j C ′ N j ( x ) , u ″ N ( x ) = ∑ j = 0 N     a j C ″ N j ( x ) (8)</p><p>Then we can convert the solution expressed by (7) and its derivative (8) to matrix form</p><p>[ u ( x ) ] = C ( x )   A       or   [ u ( x ) ] = X C A [ u ′ ( x ) ] = d   C ( x ) d x   A   or   [ u ′ ( x ) ] = X M C A [ u ″ ( x ) ] = d 2   C ( x ) d x 2   A   or   [ u ″ ( x ) ] = X M 2 C A (9)</p><p>where</p><p>A = [ a 0 , ⋯ , a N ] τ     and     C ( x ) = [ C N 0 ( x ) C N 1 ( x ) C N 2 ( x ) ⋯ C N N ( x ) ]</p><p>and</p><p>X = [ 1 x x 2 ⋯ x N ] ,   M = [ 0 1 0 … 0 0 0 2 … 0 0 0 0 ⋱ 0 0 0 0 … N 0 0 0 … 0 ] ( N + 1 ) &#215; ( N + 1 )</p><p>if N is odd,</p><p></p><p>if N is even,</p><p></p><p>Theorem 1. For C N j ( x ) defined in (5) then the finite series can be converted</p><p>u ( 3 / 2 ) ( x ) ≅ u N ( 3 / 2 ) ( x ) = ∑ j = 0 N     a j C N j ( 3 / 2 ) (x)</p><p>into matrix form</p><p>[ u ( 3 / 2 ) ( x ) ] = X D ( 3 / 2 ) C A (10)</p><p>where</p><p>D ( 3 / 2 ) = [ 0 0 0 0 0 ⋯ 0 0 0 0 0 0 ⋯ 0 0 0 Γ ( 3 ) Γ ( 3 2 )   x − 3 / 2 0 0 ⋯ 0 0 0 0 Γ ( 4 ) Γ ( 5 2 )   x − 3 / 2 0 ⋯ 0 ⋮ ⋮ ⋮ ⋮ ⋮ ⋱ ⋮ 0 0 0 0 0 … Γ ( N + 1 ) Γ ( 2 N − 1 2 )   x − 3 / 2 ] ( N + 1 ) &#215; ( N + 1 ) (11)</p><p>Proof. The proof is straightforward using Equation (4).</p></sec></sec><sec id="s3"><title>3. The Description of Chelyshkov Scheme</title><p>Let us seek the solution of (1) expressed in terms of Chelyshkov polynomials as</p><p>u ( x ) ≅ u N ( x ) = ∑ n = 0 N     a n C N n ( x ) .</p><p>Replacing each terms of (1) with the corresponding approximations defined in (7), (8) and (10) and we obtain the following theorem.</p><p>Theorem 2. If the assumed approximate solution of the boundary-value problem (1)-(2) is (3), the discrete Chelyshkov-tau system for the determination of the unknown coefficients { a n } n = 0 N is given by</p><p>A 2   ∑ n = 0 N     a n C N n ( 2 ) ( x ) + A 1   ∑ n = 0 N     a n C N n ( 3 / 2 ) ( x ) + A 0   ∑ n = 0 N     a n C N n ( x ) = ∑ n = 0 N     f n C N n ( x ) (12)</p><p>Equation (12), which can be written in the matrix form</p><p>A 2 X M 2 C A + A 1 X D ( 3 / 2 ) C A + A 0 X C A = X C F (13)</p><p>where</p><p>F = [ f 0 , f 1 , ⋯ , f N ] τ</p><p>The residual R N ( x ) for Equation (13) can be written as</p><p>R N ( x ) = X [ A 2 M 2 C A + A 1 D ( 3 / 2 ) C A + A 0 C A − C F ] (14)</p><p>As in a typical tau method [<xref ref-type="bibr" rid="scirp.81217-ref34">34</xref>] we generate N-1 linear equations by applying</p><p>〈 R N ( x ) , C N n ( x ) 〉 = ∫ 0 1   R N ( x )   C N n ( x ) d x = 0 ,   n = 1 , 2 , ⋯ , N − 1 (15)</p><p>The boundary condition is derived from Equation (2) and matrices for conditions are</p><p>∑ j = 0 1     α i j X ( 0 ) M j C A + β i j   X ( 1 ) M j C A = γ i ,   i = 0 , 1 (16)</p><p>Equations (15) and (16) generate N + 1 set of linear equations, respectively. These linear equations can be solved for unknown coefficients of the vector A . Consequently, u ( x ) given in Equation (7) can be calculated..</p></sec><sec id="s4"><title>4. Numerical Results</title><p>In this section, we apply the Chelyshkov-tau method to various problems which were collected from the open literature [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref35">35</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref36">36</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref37">37</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref38">38</xref>] . Our primary interest is to compare our method with other methods on the same problems. All computations were carried out using Matlab on a personal computer. In the examples, the maximum absolute error at points is taken as</p><p>‖ E   Chelyshkov   ‖ = | u   Exact   − u   Chelyshkov   |</p><p>Example 1: [<xref ref-type="bibr" rid="scirp.81217-ref21">21</xref>] Consider the linear BVP</p><p>u ″ ( x ) + u ( 3 / 2 ) ( x ) + u ( x ) = x + 1 ,   0 &lt; x &lt; 1</p><p>subject to the boundary conditions</p><p>u ( 0 ) = 1       and     u ( 1 ) = 2</p><p>whose exact solution is</p><p>u = x + 1</p><p>the approximate solution u ( x ) by the truncated Chelyshkov polynomial for N = 2 is</p><p>u ( x ) = a 0   C 20 ( x ) + a 1   C 21 ( x ) + a 2   C 22 (x)</p><p>Here, we have</p><p>C = [ 3 0 0 − 12 4 0 10 − 5 1 ] ,   M = [ 0 1 0 0 0 2 0 0 0 ] ,   D ( 3 / 2 ) = 4 π [ 0 0 0 0 0 0 0 0 x − 3 / 2 ]</p><p>X = [ 1 x x 2 ] ,   F = [ 1 3 5 4 35 12 ] (17)</p><p>By applying Equation (15) We obtain</p><p>( 23 3 + 16 7   π ) a 0 − ( 10 3 + 8 7   π ) a 1 + ( 2 3 + 8 35   π ) a 2 − 1 3 = 0 (18)</p><p>By applying Equation (16), we have</p><p>3   a 0 − 1 = 0 (19)</p><p>a 0 − a 1 + a 2 − 2 = 0 (20)</p><p>By solving Equations (18)-(20), we get</p><p>a 0 = 1 3 ,   a 1 = 5 4 ,   a 2 = 35 12</p><p>Thus we can write</p><p>y ( x ) = [ 1 3 5 4 35 12 ] [ 10 x 2 − 12 x + 3 − 5 x 2 + 4 x x 2 ] = 1 + x</p><p>which is the exact solution.</p><p>Example 2: [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref35">35</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref36">36</xref>] Consider the linear BVP</p><p>A 2   u ″ ( x ) + A 1   u ( 3 / 2 ) ( x ) + A 0   u ( x ) = f ( x ) ,   0 &lt; x &lt; 1</p><p>with initial conditions</p><p>u ( 0 ) = 0     and       u ′ ( 0 ) = 0</p><p>which is known to have analytical solution as</p><p>u ( x ) = ∫ 0 x   G 3 ( x − τ ) f ( τ ) d τ   G 3 ( x ) = 1 A 2   ∑ k = 0 ∞ ( − 1 ) k k ! ( A 0   A 2   ) k x 2 k + 1 E 1 2 , 2 + 3 k 2 ( k )   ( − A 1   A 2   x )</p><p>where E λ , μ ( k ) ( u ) is the kth derivative of the Mittag-Leffler function with parameters λ and μ given by</p><p>E λ , μ ( k )   ( y ) = ∑ j = 0 ∞ ( j + k ) ! y j j ! Γ ( λ j + λ k + μ ) ,   k = 0 , 1 , 2 , ⋯</p><p>and the G 3 ( x ) three-term Green’s equation. Let A 2 = 1 , A 1 = A 0 = 0.5 and f ( x ) = 8 .</p><p><xref ref-type="table" rid="table1">Table 1</xref> exhibits a comparison between the exact, the results obtained by using Chelyshkov tau for N = 14 with analogous results of &#199;enesiz et al. [<xref ref-type="bibr" rid="scirp.81217-ref35">35</xref>] for underlying the generalized Taylor collocation method (GTCM) and Setia [<xref ref-type="bibr" rid="scirp.81217-ref36">36</xref>] , who used second kind Chebyshev wavelet method (CWM) and with analogous results of El-Gamel and Abd El-Hady [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] for underlying Legendre-collocation method.</p><p><xref ref-type="fig" rid="fig1">Figure 1</xref> displays the estimated absolute error function for N = 14 with the present method.</p><p>Example 3: [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] [<xref ref-type="bibr" rid="scirp.81217-ref19">19</xref>] Now we turn to IVP</p><p>u ″ ( x ) + u ( 3 / 2 ) ( x ) + u ( x ) = 7 x + 8 π x 3 / 2 + x 3 + 1 ,   0 &lt; x &lt; 1</p><p>subject to the boundary conditions</p><p>u ( 0 ) = 1     and       u ′ ( 0 ) = 1</p><p>whose exact solution is</p><p>u ( x ) = x 3 + x + 1</p><table-wrap id="table1" ><label><xref ref-type="table" rid="table1">Table 1</xref></label><caption><title> Results for Example 2</title></caption><table><tbody><thead><tr><th align="center" valign="middle" >x</th><th align="center" valign="middle" >Analytical solution [<xref ref-type="bibr" rid="scirp.81217-ref35">35</xref>]</th><th align="center" valign="middle" >Chelyshkov N = 14</th><th align="center" valign="middle" >Ref [<xref ref-type="bibr" rid="scirp.81217-ref35">35</xref>]</th><th align="center" valign="middle" >Ref [<xref ref-type="bibr" rid="scirp.81217-ref36">36</xref>]</th><th align="center" valign="middle" >Ref [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>]</th></tr></thead><tr><td align="center" valign="middle" >0.1</td><td align="center" valign="middle" >0.036487</td><td align="center" valign="middle" >0.036453</td><td align="center" valign="middle" >0.036485</td><td align="center" valign="middle" >0.036665</td><td align="center" valign="middle" >0.036471</td></tr><tr><td align="center" valign="middle" >0.2</td><td align="center" valign="middle" >0.140639</td><td align="center" valign="middle" >0.140575</td><td align="center" valign="middle" >0.140634</td><td align="center" valign="middle" >0.140795</td><td align="center" valign="middle" >0.140615</td></tr><tr><td align="center" valign="middle" >0.3</td><td align="center" valign="middle" >0.307484</td><td align="center" valign="middle" >0.307403</td><td align="center" valign="middle" >0.307476</td><td align="center" valign="middle" >0.307622</td><td align="center" valign="middle" >0.307434</td></tr><tr><td align="center" valign="middle" >0.4</td><td align="center" valign="middle" >0.533284</td><td align="center" valign="middle" >0.533252</td><td align="center" valign="middle" >0.533271</td><td align="center" valign="middle" >0.533404</td><td align="center" valign="middle" >0.533225</td></tr><tr><td align="center" valign="middle" >0.5</td><td align="center" valign="middle" >0.814756</td><td align="center" valign="middle" >0.814860</td><td align="center" valign="middle" >0.814735</td><td align="center" valign="middle" >0.814861</td><td align="center" valign="middle" >0.814661</td></tr><tr><td align="center" valign="middle" >0.6</td><td align="center" valign="middle" >1.148837</td><td align="center" valign="middle" >1.149069</td><td align="center" valign="middle" >1.148805</td><td align="center" valign="middle" >1.148927</td><td align="center" valign="middle" >1.148733</td></tr><tr><td align="center" valign="middle" >0.7</td><td align="center" valign="middle" >1.532565</td><td align="center" valign="middle" >1.532870</td><td align="center" valign="middle" >1.532521</td><td align="center" valign="middle" >1.532643</td><td align="center" valign="middle" >1.532424</td></tr><tr><td align="center" valign="middle" >0.8</td><td align="center" valign="middle" >1.963029</td><td align="center" valign="middle" >1.963440</td><td align="center" valign="middle" >1.962974</td><td align="center" valign="middle" >1.963094</td><td align="center" valign="middle" >1.962874</td></tr><tr><td align="center" valign="middle" >0.9</td><td align="center" valign="middle" >2.437334</td><td align="center" valign="middle" >2.437829</td><td align="center" valign="middle" >2.437455</td><td align="center" valign="middle" >2.437386</td><td align="center" valign="middle" >2.437134</td></tr></tbody></table></table-wrap><p><xref ref-type="table" rid="table2">Table 2</xref> exhibits a comparison between the results obtained by using Chelyshkov tau for N = 8 with analogous results of Mekkaoui and Hammouch [<xref ref-type="bibr" rid="scirp.81217-ref19">19</xref>] for underlying the variational iteration method (VIM), the fractional iteration method (FIM) and with analogous results of El-Gamel and Abd El-Hady [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>] for underlying Legendre-collocation method.</p><p><xref ref-type="fig" rid="fig2">Figure 2</xref> displays the estimated absolute error function for N = 8 with the present method.</p><p>Example 4: [<xref ref-type="bibr" rid="scirp.81217-ref38">38</xref>] Consider the linear BVP</p><p>u ″ ( x ) + 8 17 u ( 3 / 2 ) ( x ) + 13 51 u ( x ) = f ( x ) ,   0 &lt; x &lt; 1</p><p>where</p><p>f ( x ) = 1 89250   π   x [ 48   p ( x ) + 7 x   q ( x ) ]</p><p>p ( x ) = 16000   x 4 − 32480   x 3 + 21280   x 2 − 4746   x + 149</p><p>and</p><p>q ( x ) = 3250   x 5 − 9425   x 4 + 264880   x 3 − 448107 x 2 + 233262   x − 34578</p><p>and subject to the boundary conditions</p><p>y ( 0 ) = 0       and       y ( 1 ) = 0</p><p>whose exact solution is</p><p>y ( x ) = x 5 − 29 10   x 4 + 76 25 x 3 − 339 250   x 2 + 27 125   x</p><p><xref ref-type="table" rid="table3">Table 3</xref> exhibits a comparison between the absolute errors obtained by using Chelyshkov tau for N = 8 with analogous errors of Rehman and Ali Khan [<xref ref-type="bibr" rid="scirp.81217-ref38">38</xref>] for underlying Haar wavelets method.</p><p><xref ref-type="fig" rid="fig3">Figure 3</xref> displays the estimated absolute error function for N = 8 with the present method.</p><table-wrap id="table2" ><label><xref ref-type="table" rid="table2">Table 2</xref></label><caption><title> Results for Example 3</title></caption><table><tbody><thead><tr><th align="center" valign="middle" >x</th><th align="center" valign="middle" >Exact solution</th><th align="center" valign="middle" >Chelyshkov tau N = 8</th><th align="center" valign="middle" >Ref [<xref ref-type="bibr" rid="scirp.81217-ref19">19</xref>]</th><th align="center" valign="middle" >Ref [<xref ref-type="bibr" rid="scirp.81217-ref13">13</xref>]</th></tr></thead><tr><td align="center" valign="middle" >0.10</td><td align="center" valign="middle" >1.101000</td><td align="center" valign="middle" >1.101000</td><td align="center" valign="middle" >1.103763</td><td align="center" valign="middle" >1.101000</td></tr><tr><td align="center" valign="middle" >0.25</td><td align="center" valign="middle" >1.265625</td><td align="center" valign="middle" >1.265625</td><td align="center" valign="middle" >1.269040</td><td align="center" valign="middle" >1.265625</td></tr><tr><td align="center" valign="middle" >0.50</td><td align="center" valign="middle" >1.625000</td><td align="center" valign="middle" >1.625000</td><td align="center" valign="middle" >1.623997</td><td align="center" valign="middle" >1.625000</td></tr><tr><td align="center" valign="middle" >0.75</td><td align="center" valign="middle" >2.171875</td><td align="center" valign="middle" >2.171875</td><td align="center" valign="middle" >2.166900</td><td align="center" valign="middle" >2.171875</td></tr><tr><td align="center" valign="middle" >1.00</td><td align="center" valign="middle" >3.000000</td><td align="center" valign="middle" >3.000000</td><td align="center" valign="middle" >2.994988</td><td align="center" valign="middle" >3.000002</td></tr></tbody></table></table-wrap><table-wrap id="table3" ><label><xref ref-type="table" rid="table3">Table 3</xref></label><caption><title> Results for Example 4</title></caption><table><tbody><thead><tr><th align="center" valign="middle" >x</th><th align="center" valign="middle" >Haar wavelets ( N = 256 ) [<xref ref-type="bibr" rid="scirp.81217-ref38">38</xref>]</th><th align="center" valign="middle" >Chelyshkov tau ( N = 8 )</th></tr></thead><tr><td align="center" valign="middle" >0.1</td><td align="center" valign="middle" >6.49908E−7</td><td align="center" valign="middle" >5.92720E−14</td></tr><tr><td align="center" valign="middle" >0.2</td><td align="center" valign="middle" >6.35657E−7</td><td align="center" valign="middle" >1.18400E−13</td></tr><tr><td align="center" valign="middle" >0.3</td><td align="center" valign="middle" >3.71584E−7</td><td align="center" valign="middle" >1.77249E−13</td></tr><tr><td align="center" valign="middle" >0.4</td><td align="center" valign="middle" >9.48220E−7</td><td align="center" valign="middle" >2.35568E−13</td></tr><tr><td align="center" valign="middle" >0.5</td><td align="center" valign="middle" >1.59573E−6</td><td align="center" valign="middle" >2.17578E−13</td></tr><tr><td align="center" valign="middle" >0.6</td><td align="center" valign="middle" >1.05494E−6</td><td align="center" valign="middle" >2.92504E−13</td></tr><tr><td align="center" valign="middle" >0.7</td><td align="center" valign="middle" >6.34678E−7</td><td align="center" valign="middle" >3.82671E−13</td></tr><tr><td align="center" valign="middle" >0.8</td><td align="center" valign="middle" >1.88690E−6</td><td align="center" valign="middle" >3.82256E−13</td></tr><tr><td align="center" valign="middle" >0.9</td><td align="center" valign="middle" >3.13999E−6</td><td align="center" valign="middle" >2.90107E−13</td></tr></tbody></table></table-wrap></sec><sec id="s5"><title>5. Conclusion</title><p>In this paper, Chelyshkov operational matrix of fractional derivative has been derived. Our approach was based on the tau method. The proposed technique is easy to implement efficiently and yield accurate results. Moreover, only a small number of Chelyshkov polynomials is needed to obtain a satisfactory result. In addition, an interesting feature of this method is to find the analytical solution if the equation has an exact solution that is polynomial functions. Numerical examples are included and a comparison is made with an existing result.</p></sec><sec id="s6"><title>Cite this paper</title><p>El-Gamel, M., Abd-El-Hady, M. and El-Azab, M. (2017) Chelyshkov-Tau Approach for Solving Bagley-Torvik Equation. Applied Mathematics, 8, 1795-1807. https://doi.org/10.4236/am.2017.812128</p></sec></body><back><ref-list><title>References</title><ref id="scirp.81217-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">Luchko, Y. and Gorenflo, R. (1999) An Operational Method for Solving Fractional Differential Equations with the Caputo Derivatives. Acta Mathematica Vietnamica, 24, 207-233.</mixed-citation></ref><ref id="scirp.81217-ref2"><label>2</label><mixed-citation publication-type="other" xlink:type="simple">Podlubny, I. (1999) Fractional Differential Equations. Academic Press, San Diego.</mixed-citation></ref><ref id="scirp.81217-ref3"><label>3</label><mixed-citation publication-type="other" xlink:type="simple">Meerschaert, T. and Tadjeran, C. (2006) Finite Difference Approximations for Two-Sided Space-Fractional Partial Differential Equations. Applied Numerical Mathematics, 56, 80-90. &lt;br /&gt;https://doi.org/10.1016/j.apnum.2005.02.008</mixed-citation></ref><ref id="scirp.81217-ref4"><label>4</label><mixed-citation publication-type="other" xlink:type="simple">Esmaeili, S. and Shamsia, M. and Luchko, Y. (2011) Numerical Solution of Fractional Differential Equations with a Collocation Method Based on Müntz Polynomials. Computers &amp; Mathematics with Applications, 62, 918-929. 
https://doi.org/10.1016/j.camwa.2011.04.023</mixed-citation></ref><ref id="scirp.81217-ref5"><label>5</label><mixed-citation publication-type="other" xlink:type="simple">Vanani, S. and Aminataei, A. (2011) Tau Approximate Solution of Fractional Partial Differential Equations. Computers &amp; Mathematics with Applications, 62, 1075-1083. &lt;br /&gt;https://doi.org/10.1016/j.camwa.2011.03.013</mixed-citation></ref><ref id="scirp.81217-ref6"><label>6</label><mixed-citation publication-type="other" xlink:type="simple">Momani, S. and Al-Khaled, K. (2005) Numerical Solutions for Systems of Fractional Differential Equations by the Decomposition Method. Computers &amp; Mathematics with Applications, 162, 1351-1365. &lt;br /&gt;https://doi.org/10.1016/j.amc.2004.03.014</mixed-citation></ref><ref id="scirp.81217-ref7"><label>7</label><mixed-citation publication-type="other" xlink:type="simple">Ray, S. and Bera, R. (2005) Analytical Solution of the Bagley-Torvik Equation by Adomian Decomposition Method. Applied Mathematics and Computation, 168, 398-410. &lt;br /&gt;https://doi.org/10.1016/j.amc.2004.09.006</mixed-citation></ref><ref id="scirp.81217-ref8"><label>8</label><mixed-citation publication-type="other" xlink:type="simple">Odibat, Z. and Momani, S. (2006) Application of Variational Iteration Method to Nonlinear Differential Equations of Fractional Order. International Journal of Nonlinear Sciences and Numerical Simulation, 70, 27-34. 
https://doi.org/10.1515/IJNSNS.2006.7.1.27</mixed-citation></ref><ref id="scirp.81217-ref9"><label>9</label><mixed-citation publication-type="other" xlink:type="simple">Li, Y. and Sun, N. (2011) Numerical Solution of Fractional Differential Equations Using the Generalized Block Pulse Operational Matrix. Computers &amp; Mathematics with Applications, 62, 1046-1054. https://doi.org/10.1016/j.camwa.2011.03.032</mixed-citation></ref><ref id="scirp.81217-ref10"><label>10</label><mixed-citation publication-type="other" xlink:type="simple">Odibat, Z. (2008) Compact and Noncompact Structures for Nonlinear Fractional Evolution Equations. Physics Letters A, 372, 1219-1227. 
https://doi.org/10.1016/j.physleta.2007.09.022</mixed-citation></ref><ref id="scirp.81217-ref11"><label>11</label><mixed-citation publication-type="other" xlink:type="simple">Ganji, Z., Jafari, H. and Rostamian, M. (2008) Application of the Homotopy Perturbation Method to Coupled System of Partial Differential Equations with Time Fractional Derivatives. Topological Methods in Nonlinear Analysis, 31, 341-348.</mixed-citation></ref><ref id="scirp.81217-ref12"><label>12</label><mixed-citation publication-type="other" xlink:type="simple">Odibat, Z. and Odibat, S. (2008) Generalized Differential Transform Method for Linear Partial Differential Equations of Fractional Order. Applied Mathematics Letters, 31, 194-199. https://doi.org/10.1016/j.aml.2007.02.022</mixed-citation></ref><ref id="scirp.81217-ref13"><label>13</label><mixed-citation publication-type="other" xlink:type="simple">El-Gamel, M. and Abd El-Hady, M. (2017) Numerical Solution of the Bagley-Torvik Equation by Legendre-Collocation Method. SeMA Journal, 74, 371-383. 
https://doi.org/10.1007/s40324-016-0089-6</mixed-citation></ref><ref id="scirp.81217-ref14"><label>14</label><mixed-citation publication-type="other" xlink:type="simple">Uddin, M. and Ahmad S. (2017) On the Numerical Solution of Bagley-Torvik Equation via the Laplace Transform. Tbilisi Mathematical Journal, 10, 279-284. 
&lt;br /&gt;https://doi.org/10.1515/tmj-2017-0017</mixed-citation></ref><ref id="scirp.81217-ref15"><label>15</label><mixed-citation publication-type="other" xlink:type="simple">Gaul, L., Klein, P. and Kemple, S. (1991) Damping Description Involving Fractional Operators. Mechanical Systems and Signal Processing, 5, 81-88. 
&lt;br /&gt;https://doi.org/10.1016/0888-3270(91)90016-X</mixed-citation></ref><ref id="scirp.81217-ref16"><label>16</label><mixed-citation publication-type="other" xlink:type="simple">Suarez, L., Shokooh, A. and Kemple, S. (1991) An Eigenvector Expansion Method for the Solution of Motion Containing Fractional Derivatives. Journal of Applied Mechanics, 64, 629-635. https://doi.org/10.1115/1.2788939</mixed-citation></ref><ref id="scirp.81217-ref17"><label>17</label><mixed-citation publication-type="other" xlink:type="simple">Arikoglu, A. and Ozkol, I. (2009) Solution of Fractional Integro-Differential Equations by Using Fractional Differential Transform Method. Chaos, Solitons &amp; Fractals, 40, 521-529. &lt;br /&gt;https://doi.org/10.1016/j.chaos.2007.08.001</mixed-citation></ref><ref id="scirp.81217-ref18"><label>18</label><mixed-citation publication-type="other" xlink:type="simple">Mekkaouii, T. and Hammouch, Z. (2012) Application of Generalized Differential Transform Method to Multi-Order Fractional Differential Equations. Mathematics in Computer Science, 39, 251-256.</mixed-citation></ref><ref id="scirp.81217-ref19"><label>19</label><mixed-citation publication-type="other" xlink:type="simple">Mekkaouii, T. and Hammouch, Z. (2012) Approximate Analytical Solutions to the Bagley-Torvik Equation by the Fractional Iteration Method. Mathematics in Computer Science, 38, 251-256.</mixed-citation></ref><ref id="scirp.81217-ref20"><label>20</label><mixed-citation publication-type="other" xlink:type="simple">Odibat, Z. and Shawagfeh, N. (2007) Generalized Taylor Formula. Applied Mathematics and Computation, 186, 286-293. https://doi.org/10.1016/j.amc.2006.07.102</mixed-citation></ref><ref id="scirp.81217-ref21"><label>21</label><mixed-citation publication-type="other" xlink:type="simple">Yzba, S. and Shawagfeh, N. (2013) Numerical Solution of the Bagley-Torvik Equation by the Bessel Collocation Method. Mathematical Methods in the Applied Sciences, 36, 300-312. https://doi.org/10.1002/mma.2588</mixed-citation></ref><ref id="scirp.81217-ref22"><label>22</label><mixed-citation publication-type="other" xlink:type="simple">Wu, J.L. (2013) A Wavelet Operational Method for Solving Fractional Partial Differential Equations Numerically. Applied Mathematics and Computation, 214, 31-40.  
&lt;br /&gt;https://doi.org/10.1016/j.amc.2009.03.066</mixed-citation></ref><ref id="scirp.81217-ref23"><label>23</label><mixed-citation publication-type="other" xlink:type="simple">Lepik, H. (2009) Solving Fractional Integral Equations by the Haar Wavelet Method. Applied Mathematics and Computation, 214, 468-678.  
https://doi.org/10.1016/j.amc.2009.04.015</mixed-citation></ref><ref id="scirp.81217-ref24"><label>24</label><mixed-citation publication-type="other" xlink:type="simple">Oguz, C. and Sezer, M. (2015) Chelyshkov Collocation Method for a Class of Mixed Functional Integro-Differential Equations. Applied Mathematics and Computation, 259, 943-954. &lt;br /&gt;https://doi.org/10.1016/j.amc.2015.03.024</mixed-citation></ref><ref id="scirp.81217-ref25"><label>25</label><mixed-citation publication-type="other" xlink:type="simple">Oguz, C., Sezer, M. and Denk Oguz, A. (2015) Chelyshkov Collocation Approach to Solve the Systems of Linear Functional Differential Equations. NTMSCI, 3, 83-97.</mixed-citation></ref><ref id="scirp.81217-ref26"><label>26</label><mixed-citation publication-type="other" xlink:type="simple">Hilfer, R. (2000) Applications of Fractional Calculus in Physics. World Scientific Publishing Company, Singapore. https://doi.org/10.1142/3779</mixed-citation></ref><ref id="scirp.81217-ref27"><label>27</label><mixed-citation publication-type="other" xlink:type="simple">Diethelm, K. (1982) The Analysis of Fractional Differential Equations. Springer-Verlag, Berlin Heidelberg.</mixed-citation></ref><ref id="scirp.81217-ref28"><label>28</label><mixed-citation publication-type="other" xlink:type="simple">Caputo, M. and Sezer, M. (1967) Linear Models of Dissipation Whose Q Is Almost Frequency Independent. Part II. Geophysical Journal of the Royal Astronomical Society, 13, 529-539. https://doi.org/10.1111/j.1365-246X.1967.tb02303.x</mixed-citation></ref><ref id="scirp.81217-ref29"><label>29</label><mixed-citation publication-type="other" xlink:type="simple">Chelyshkov, V. and Sezer, M. (1974) Stability of the Rest Position of the Inner Cylinder in a Couette Flow. Fluid Dynamics, 6, 1003-1005.</mixed-citation></ref><ref id="scirp.81217-ref30"><label>30</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Chelyshkov</surname><given-names> V. </given-names></name>,<etal>et al</etal>. (<year>1982</year>)<article-title>Three-Dimensional Self-Oscillatory Regimes of Fluid Flows</article-title><source> Hydromech</source><volume> 4</volume>,<fpage> 53</fpage>-<lpage>57</lpage>.<pub-id pub-id-type="doi"></pub-id></mixed-citation></ref><ref id="scirp.81217-ref31"><label>31</label><mixed-citation publication-type="other" xlink:type="simple">Chelyshkov, V. (1986) Using the Method of Integration with Respect to a Small Parameter for Calculating a Laminar Boundary Layer on a Cylinder. USSR Computational Mathematics and Mathematical Physics, 26, 94-96.  
https://doi.org/10.1016/0041-5553(86)90047-9</mixed-citation></ref><ref id="scirp.81217-ref32"><label>32</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Chelyshkov</surname><given-names> V. </given-names></name>,<etal>et al</etal>. (<year>2006</year>)<article-title>Alternative Orthogonal Polynomials and Quadratures</article-title><source> ETNA</source><volume> 25</volume>,<fpage> 17</fpage>-<lpage>26</lpage>.<pub-id pub-id-type="doi"></pub-id></mixed-citation></ref><ref id="scirp.81217-ref33"><label>33</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Chelyshkov</surname><given-names> V. </given-names></name>,<etal>et al</etal>. (<year>1994</year>)<article-title>A Variant of Spectral Method in the Theory of Hydrodynamic Stability</article-title><source> Hydromech</source><volume> 68</volume>,<fpage> 105</fpage>-<lpage>109</lpage>.<pub-id pub-id-type="doi"></pub-id></mixed-citation></ref><ref id="scirp.81217-ref34"><label>34</label><mixed-citation publication-type="other" xlink:type="simple">Canuto, C., Hussaini, M. and Quarteroni, A. (1988) Spectral Method in Fluid Dynamic. Prentice-HLL, Englewood Cliffs. https://doi.org/10.1007/978-3-642-84108-8</mixed-citation></ref><ref id="scirp.81217-ref35"><label>35</label><mixed-citation publication-type="other" xlink:type="simple">?enesiz, Y., Keskin, Y. and Kurnaz, A. (2010) The Solution of the Bagley-Torvik Equation with the Generalized Taylor Collocation Method. Journal of the Franklin Institute, 347, 452-466. https://doi.org/10.1016/j.jfranklin.2009.10.007 </mixed-citation></ref><ref id="scirp.81217-ref36"><label>36</label><mixed-citation publication-type="other" xlink:type="simple">Setia, A., Liu, Y. and Vatsala, A. (2014) The Solution of the Bagley-Torvik Equation by Using Second Kind Chebyshev Wavelet. 11th International Conference on Information Technology.</mixed-citation></ref><ref id="scirp.81217-ref37"><label>37</label><mixed-citation publication-type="other" xlink:type="simple">Bagly, R. and Torvik, P. (1984) On the Appearance of the Fractionl Derivative in the Behavior of Real Materials. Journal of Applied Mechanics, 51, 294-298.  
https://doi.org/10.1115/1.3167615</mixed-citation></ref><ref id="scirp.81217-ref38"><label>38</label><mixed-citation publication-type="other" xlink:type="simple">Rehman, M. and Ali Khan, R. (2012) A Numerical Method for Solving Boundary Value Problems for Fractionl Differential Equation. Applied Mathematical Modelling, 36, 894-907. &lt;br /&gt;https://doi.org/10.1016/j.apm.2011.07.045</mixed-citation></ref></ref-list></back></article>