<?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.2012.34046</article-id><article-id pub-id-type="publisher-id">AM-18874</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>
 
 
  Some New Exact Traveling Wave Solutions for the Generalized Benney-Luke (GBL) Equation with Any Order
 
</article-title></title-group><contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>un-Jie</surname><given-names>Wang</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>Lian-Tang</surname><given-names>Wang</given-names></name><xref ref-type="aff" rid="aff2"><sup>2</sup></xref></contrib><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Kuan-De</surname><given-names>Yang</given-names></name><xref ref-type="aff" rid="aff1"><sup>1</sup></xref></contrib></contrib-group><aff id="aff2"><addr-line>Mathematics Department, Northwest University, Xi’an, China</addr-line></aff><aff id="aff1"><addr-line>Mathematics Department, Simao Teachers’ College, Pu’er, China</addr-line></aff><author-notes><corresp id="cor1">* E-mail:<email>wangjunjie6688@sina.com(UW)</email>;</corresp></author-notes><pub-date pub-type="epub"><day>27</day><month>04</month><year>2012</year></pub-date><volume>03</volume><issue>04</issue><fpage>309</fpage><lpage>314</lpage><history><date date-type="received"><day>December</day>	<month>5,</month>	<year>2011</year></date><date date-type="rev-recd"><day>February</day>	<month>22,</month>	<year>2012</year>	</date><date date-type="accepted"><day>February</day>	<month>29,</month>	<year>2012</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>
 
 
  In the paper, a auxiliary equation expansion method and its algorithm is proposed by studying a second order nonlinear ordinary differential equation with a four-degree term. The method is applied to the generalized Ben-ney-Luke (GBL) equation with any order. As a result, some new exact traveling wave solutions are obtained which singular solutions, triangular periodic wave solutions and jacobian elliptic function solutions .This algorithm can also be applied to other nonlinear wave equations in mathematical physics.
 
</p></abstract><kwd-group><kwd>Generalized Benney-Luke (GBL) Equation; Jacobian Elliptic Function; Singular Solution</kwd></kwd-group></article-meta></front><body><sec id="s1"><title>1. Introduction</title><p>Nonlinear phenomena that appear in many areas of scientific fields such as solid state physics, plasma physics, fluid dynamics, mathematical biology and chemical kinetics can be modeled by partial differential equation. A broad class of analytical solutions methods and numerical solutions methods were used in handle these problems. The investigation of exact traveling wave solution to nonlinear equations plays an important role in the study of nonlinear physical phenomena. Various methods for seeking traveling wave solutions to nonlinear partial differential equations are proposed such as inverse scattering transform method [<xref ref-type="bibr" rid="scirp.18874-ref1">1</xref>], B&#196;acklund and Darboux transform [2-6], Hirota method [<xref ref-type="bibr" rid="scirp.18874-ref7">7</xref>], Lie group method [8,9] and so on.</p><p>In the paper, we shall consider the following generalized Benney-Luke (GBL) equation [<xref ref-type="bibr" rid="scirp.18874-ref10">10</xref>]:</p><disp-formula id="scirp.18874-formula9953"><label>(1.1)</label><graphic position="anchor" xlink:href="1-7400685\a5f6e86e-baa4-4d04-a120-320ba3288426.jpg"  xlink:type="simple"/></disp-formula><p>The paper is organized as follows. In Section 2, we present the auxiliary equation method and its algorithm. In Section 3, we present some exact traveling wave solutions of system (1.1). Finally some conclusion are given.</p></sec><sec id="s2"><title>2. The Auxiliary Equation Algorithm</title><p>We outline our auxiliary equation algorithm:</p><p>Step I. For a given nonlinear wave equation with one physical field<img src="1-7400685\7e54d92c-3e22-4e5f-8b9d-cd08b5e1eaa9.jpg" />; in three variables <img src="1-7400685\7020498d-21ea-437a-9271-e6371a95fac9.jpg" /></p><disp-formula id="scirp.18874-formula9954"><label>(2.1)</label><graphic position="anchor" xlink:href="1-7400685\3cb269af-10df-4e57-95c6-4385527b9dda.jpg"  xlink:type="simple"/></disp-formula><p>We seek its special solution, traveling wave solution, in the form of</p><disp-formula id="scirp.18874-formula9955"><label>(2.2)</label><graphic position="anchor" xlink:href="1-7400685\1a383511-6b42-43b9-853e-387d2467041f.jpg"  xlink:type="simple"/></disp-formula><p>where <img src="1-7400685\a18427df-c8fc-4637-8ed3-769825ec4d63.jpg" /> is constant. Substitution (2.2) into (2.1) gives rise to a nonlinear ordinary differential equation</p><disp-formula id="scirp.18874-formula9956"><label>(2.3)</label><graphic position="anchor" xlink:href="1-7400685\5d44538f-bd07-47ff-ab8c-d47baaa26f19.jpg"  xlink:type="simple"/></disp-formula><p>Step II. To seek the traveling wave solution of (2.3), we assume that (2.3) has the solution in the form of</p><disp-formula id="scirp.18874-formula9957"><label>(2.4)</label><graphic position="anchor" xlink:href="1-7400685\33961823-f9dd-478b-94b4-eea6263ed58d.jpg"  xlink:type="simple"/></disp-formula><p>with the new variable <img src="1-7400685\aead69ec-3a7e-4cea-9802-825fb90a6f67.jpg" /> satisfying:</p><disp-formula id="scirp.18874-formula9958"><label>(2.5)</label><graphic position="anchor" xlink:href="1-7400685\a728edb9-eac2-483d-8426-b580b03a5e8f.jpg"  xlink:type="simple"/></disp-formula><p><img src="1-7400685\81a0d326-7905-4cf8-9c4a-2c2013025378.jpg" />are constants and <img src="1-7400685\9d289bef-ce7e-415f-a7a8-679819f20211.jpg" /> is the integer to be determined later.</p><p>Step III. Determined the parameter<img src="1-7400685\098982b9-07b9-4372-91b8-afcb3479c132.jpg" />. Substituing Equation (2.4) along with Equation (2.5) into Equation (2.3) and balancing the highest derivative term with the nonlinear terms in the Equation (2.3), we then obtain the value of<img src="1-7400685\c19c1ca1-4304-4d5e-b761-a2fc0e46d949.jpg" />.</p><p>Step IV. Determine the parameters</p><p><img src="1-7400685\2de39185-d8cb-40e7-bee1-ce6c1a39af42.jpg" /></p><p>Substitution Equation (2.4) along with Equation (2.5) into Equation (2.3) and setting the coefficients of all powers <img src="1-7400685\d71b86fc-a309-41de-be04-1ccb0d3d27e0.jpg" /> to zero, we will obtain a system of nonlinear algebraic equations (NAEs) with respect to the parameters</p><p><img src="1-7400685\b6942ad4-00f3-4b83-a498-1de7fbcf3a3e.jpg" /></p><p>By solving the NAEs if available, we can determine those parameters explicitly.</p></sec><sec id="s3"><title>3. Exact Traveling Wave Solutions for the Generalized Benney-Luke (GBL) Equation with Any Order</title><p>By considering that the traveling wave solutions of (1.1) propagate in the direction of the positive x-axis, i.e. <img src="1-7400685\ac391b10-fff2-4fca-b12f-fc5e4ffeaedb.jpg" />Ref. [<xref ref-type="bibr" rid="scirp.18874-ref10">10</xref>] gave the following traveling equation:</p><disp-formula id="scirp.18874-formula9959"><label>(3.1)</label><graphic position="anchor" xlink:href="1-7400685\8c34d218-2135-4533-9df5-8346eb607e30.jpg"  xlink:type="simple"/></disp-formula><p>In this paper, we will study the traveling wave solutions of (1.1) with the form:</p><p><img src="1-7400685\c49e315f-7c7a-4d9f-9e75-c8255ea4a79a.jpg" /></p><p>where c is the wave speed. Substituting it into (1.1) and noting (3.1), we have</p><disp-formula id="scirp.18874-formula9960"><label>(3.2)</label><graphic position="anchor" xlink:href="1-7400685\68f70966-48a1-46e3-b425-c71523502f4a.jpg"  xlink:type="simple"/></disp-formula><p>Integrating (3.2) once with respect to <img src="1-7400685\fc61c221-64d6-4670-8b85-f962f7b7cd4e.jpg" /> and taking the integral constant as zero, we obtain</p><disp-formula id="scirp.18874-formula9961"><label>(3.3)</label><graphic position="anchor" xlink:href="1-7400685\b0c63ecc-a4af-46a2-8bdb-a7dbf8633967.jpg"  xlink:type="simple"/></disp-formula><p>Letting</p><disp-formula id="scirp.18874-formula9962"><label>(3.4)</label><graphic position="anchor" xlink:href="1-7400685\e92ef91b-b98f-48f3-a11e-a7b44567d7e7.jpg"  xlink:type="simple"/></disp-formula><p>and writing</p><p><img src="1-7400685\76202dff-d2dc-4426-a0c2-9d4bdece64d3.jpg" /></p><p>then from (3.4), we have that</p><disp-formula id="scirp.18874-formula9963"><label>(3.5)</label><graphic position="anchor" xlink:href="1-7400685\63c590e8-0ce6-4a0a-8f1c-958c92564666.jpg"  xlink:type="simple"/></disp-formula><p>Let</p><p><img src="1-7400685\16c617c3-4754-4cc0-9844-3ba6241f1d72.jpg" /></p><p>We have</p><disp-formula id="scirp.18874-formula9964"><label>(3.6)</label><graphic position="anchor" xlink:href="1-7400685\e8b528ca-662f-4ec9-a275-9746ea20cb9d.jpg"  xlink:type="simple"/></disp-formula><p>We expand the solution of Equation (3.6) in form of Equation (2.4). Substitution Equation (2.4) along with Equation (2.5) and balancing the highest order derivative term.</p><p><img src="1-7400685\6fa1cbf1-4a1a-4e8e-ad25-1dd9f44080a4.jpg" />with nonlinear term <img src="1-7400685\1234c79b-050a-4fbe-acad-4328c6344b8b.jpg" /> in Equation (3.6) gives<img src="1-7400685\6ec2ef98-d5e7-4014-b045-6d6195ef0852.jpg" />. Hence, we have</p><disp-formula id="scirp.18874-formula9965"><label>(3.7)</label><graphic position="anchor" xlink:href="1-7400685\744697dc-1ed1-48ae-9bbf-210af4b4be51.jpg"  xlink:type="simple"/></disp-formula><p>where<img src="1-7400685\c8e59fe3-1f36-47ff-8ce5-6b7fd3f5ef7a.jpg" />are constant to be determined later; <img src="1-7400685\eabbef12-6ceb-4d2b-90d4-5c15bb8ac3af.jpg" />satifiyed Equation (2.5).</p><p>We can get the following equation by Step IV</p><disp-formula id="scirp.18874-formula9966"><label>(3.8)</label><graphic position="anchor" xlink:href="1-7400685\e317ca42-14c4-4657-bcc5-ad29e05e29e0.jpg"  xlink:type="simple"/></disp-formula><p>If<img src="1-7400685\07048cb6-1c33-43b3-9b52-d7d6cd7f21a7.jpg" />, we can get the following solution:</p><p><img src="1-7400685\df4c5e14-402c-4d28-b8b8-57bc3115ee44.jpg" /></p><p><img src="1-7400685\54a0bae3-d28c-4a6d-ac20-2d013d57e2fb.jpg" /></p><p><img src="1-7400685\8a7e86dd-2c33-40e9-9c00-7d7764949361.jpg" /></p><p><img src="1-7400685\bdceb404-67eb-44e7-b181-e0bd0e319cc7.jpg" /></p><p><img src="1-7400685\103cfb83-0186-41fa-ada4-1cacb8aa1fa2.jpg" /></p><disp-formula id="scirp.18874-formula9967"><label>(3.9)</label><graphic position="anchor" xlink:href="1-7400685\fa599402-2f88-4bc3-811c-491500efa49a.jpg"  xlink:type="simple"/></disp-formula><p>where</p><disp-formula id="scirp.18874-formula9968"><label>(3.10)</label><graphic position="anchor" xlink:href="1-7400685\0f9d6231-3232-4627-8734-d9f52937dbfd.jpg"  xlink:type="simple"/></disp-formula><p>Th 3.1. Suppose that</p><p><img src="1-7400685\4e256884-6911-48d7-9481-e7e5282afe8e.jpg" /></p><p>If<img src="1-7400685\0f70052f-3cbb-40f9-b1b5-1742ea7e0dc0.jpg" />, that Equation (1.1) has a kink profile solution</p><p><img src="1-7400685\b86bca77-4398-40f2-916d-d9a2e75c35fa.jpg" /></p><p>Th 3.2. 1) If</p><p><img src="1-7400685\0bcc2fae-edf6-49d4-89ca-8a285f34d2fc.jpg" /></p><p>that Equation (1.1) has two Jacobian elliptic function solutions</p><p><img src="1-7400685\ae82522e-04eb-41f7-bac7-08c6bf070ee2.jpg" /></p><p><img src="1-7400685\8520caf5-80ee-49f8-80c7-9aa2bb18fbdd.jpg" /></p><p>2) If</p><p><img src="1-7400685\69739832-8fa0-4e95-b302-455d91083249.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\1b7e92fe-ea10-42c9-a77c-41fa73d12d29.jpg" /></p><p>3) If</p><p><img src="1-7400685\075bfa02-5b91-48fa-b161-b06db95818a8.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\c675061f-7a54-462d-bb2f-0e748c70a7bc.jpg" /></p><p>4) If</p><p><img src="1-7400685\4a89ef62-84ff-4b61-bcff-b7b7157f4cca.jpg" /></p><p>that Equation (1.1) has two Jacobian elliptic function solutions</p><p><img src="1-7400685\d3fc9e2d-a05c-4ad5-9abc-4052ba62bf54.jpg" /></p><p><img src="1-7400685\dd5cc8b7-3551-48e0-8256-113ffecb28fd.jpg" /></p><p>5) If</p><p><img src="1-7400685\44230181-6054-4bea-ad2e-0d99fcb92ebd.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\e59e514f-5c50-4b4b-9909-9f2624d119ef.jpg" /></p><p>6) If</p><p><img src="1-7400685\6ca8fe7b-0f81-48e1-b449-1643400920b1.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\0dd621c5-8f75-405c-9203-449e6d135099.jpg" /></p><p>7) If</p><p><img src="1-7400685\a1e04768-e75c-4ac2-ba9f-aaec86c9a12a.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\e2387ee5-d041-43d8-835e-d361835fd2bf.jpg" /></p><p>8) If</p><p><img src="1-7400685\3d84d794-f6c1-4b6f-87a3-61153de75e56.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\064a78ab-8fda-4adb-9b58-5527883e323a.jpg" /></p><p>9) If</p><p><img src="1-7400685\d844bd50-7bf0-454c-ba80-0f8c4794eec1.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\acfb7ba1-afdb-442b-8a10-15bf60d2b3e6.jpg" /></p><p>10) If</p><p><img src="1-7400685\93d54457-fcbe-4ae9-ae00-58a7b048291d.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\1f1a6f45-8a32-4bbc-9f88-18a4838a6c50.jpg" /></p><p>11) If</p><p><img src="1-7400685\d28b9ebc-1ba6-44c4-bf4a-ab2bfa8b1124.jpg" /></p><p>that Equation (1.1) has four Jacobian elliptic function solutions</p><p><img src="1-7400685\54cb848e-ed74-49c4-a4e5-4bfdf352bd47.jpg" /></p><p><img src="1-7400685\028bf390-218e-49e6-94eb-2a9015c45e49.jpg" /></p><p><img src="1-7400685\2fe30c8a-951c-4a45-b796-cb0e810871a4.jpg" /></p><p><img src="1-7400685\54de662b-412c-458f-a03d-d18665590fbc.jpg" /></p><p>12) If</p><p><img src="1-7400685\6d59f489-f0cc-4986-9586-8f4d890e1853.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\1cbf3b2a-ecd4-4782-985d-df3bb294edf2.jpg" /></p><p>13) If</p><p><img src="1-7400685\daa69235-2f59-4afa-98c6-0e15e9f70f5b.jpg" /></p><p>that Equation (1.1) has three Jacobian elliptic function solutions</p><p><img src="1-7400685\ef8dd8c1-4bb0-4d35-8a44-dc3175b88380.jpg" /></p><p><img src="1-7400685\ed099f0e-e4d1-43ba-9f5b-1955ced073d4.jpg" /></p><p><img src="1-7400685\794559d5-aca4-4b53-b689-1e74f5a151bd.jpg" /></p><p>14) If</p><p><img src="1-7400685\98f63353-8d57-4b48-81e3-8aa809c65163.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\7a3603c4-93fd-422e-94b0-974e12ffabbf.jpg" /></p><p>15) If</p><p><img src="1-7400685\b52b6eb8-b01a-4429-a162-a7a06b907789.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\d16ae85e-d0e9-419a-ad38-874421bf6e8c.jpg" /></p><p>16) If</p><p><img src="1-7400685\04b87658-2873-4bf4-934e-3289ea44df2c.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\1521a3bb-7dd1-49d5-bdb6-8a914c68e7c6.jpg" /></p><p>17) If</p><p><img src="1-7400685\8c7e1c70-b30f-4884-b0ac-08bf9b541a4c.jpg" /></p><p>that Equation (1.1) has a Jacobian elliptic function solution</p><p><img src="1-7400685\916b95e9-f644-4f8b-8791-a2aa1e10e0b1.jpg" /></p></sec><sec id="s4"><title>4. Conclusion</title><p>In the paper, we apply the auxiliary equation method to study Equation (1.1), and get some new conclusions. Some new exact traveling wave solution of Equation (1.1) are obtain which include new singular solution, triangular periodic wave solutions and Jacobian elliptic function solutions. These solutions may be useful for describing certain nonlinear physical phenomena of Equation (1.1). The method which we have propose in this paper is standard, direct and computerized method ,which allow us to do complicated and tedious algebraic calculation.It is shown that the algorithm can be also applied to other nonlinear wave equations such as generalized BBM equation,</p><p><img src="1-7400685\5f8c6eb9-c0b6-4b3f-bca0-e42655911b11.jpg" /></p><p>and generalized Klein-Gordon equation:</p><p><img src="1-7400685\e6b72d85-7294-4bfb-96a0-3fc2f3b8b32b.jpg" /></p></sec><sec id="s5"><title>REFERENCES</title></sec></body><back><ref-list><title>References</title><ref id="scirp.18874-ref1"><label>1</label><mixed-citation publication-type="other" xlink:type="simple">M. J. Ablowitz and P. A. Clarkson, “Solution, Nonlinearn Evolution Equations and Inverse Scateing,” Cambridge University Press, Cambridge, 1991.  
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