Research Article Traveling Wave Solutions of a Generalized ...traveling wave system ( ) to get the...

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Research Article Traveling Wave Solutions of a Generalized Camassa-Holm Equation: A Dynamical System Approach Lina Zhang and Tao Song Department of Mathematics, Huzhou University, Huzhou, Zhejiang 313000, China Correspondence should be addressed to Lina Zhang; [email protected] Received 1 August 2015; Accepted 14 September 2015 Academic Editor: Maria Gandarias Copyright Β© 2015 L. Zhang and T. Song. is 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. We investigate a generalized Camassa-Holm equation (3, 2, 2): + + 1 + 2 ( 3 ) + 3 ( 2 ) + 3 ( 2 ) =0. We show that the (3, 2, 2) equation can be reduced to a planar polynomial differential system by transformation of variables. We treat the planar polynomial differential system by the dynamical systems theory and present a phase space analysis of their singular points. Two singular straight lines are found in the associated topological vector field. Moreover, the peakon, peakon-like, cuspon, smooth soliton solutions of the generalized Camassa-Holm equation under inhomogeneous boundary condition are obtained. e parametric conditions of existence of the single peak soliton solutions are given by using the phase portrait analytical technique. Asymptotic analysis and numerical simulations are provided for single peak soliton, kink wave, and kink compacton solutions of the (3, 2, 2) equation. 1. Introduction Mathematical modeling of dynamical systems processing in a great variety of natural phenomena usually leads to nonlinear partial differential equations (PDEs). ere is a special class of solutions for nonlinear PDEs that are of considerable interest, namely, the traveling wave solutions. Such a wave may be localized or periodic, which propagates at constant speed without changing its shape. Many powerful methods have been presented for finding the traveling wave solutions, such as the BΒ¨ acklund trans- formation [1], tanh-coth method [2], bilinear method [3], symbolic computation method [4], and Lie group analysis method [5]. Furthermore, a great amount of works focused on various extensions and applications of the methods in order to simplify the calculation procedure. e basic idea of those methods is that, by introducing different types of Ansatz, the original PDEs can be transformed into a set of algebraic equations. Balancing the same order of the Ansatz then yields explicit expressions for the PDE waves. However, not all of the special forms for the PDE waves can be derived by those methods. In order to obtain all possible forms of the PDE waves and analyze qualitative behaviors of solutions, the bifurcation theory plays a very important role in studying the evolution of wave patterns with variation of parameters [6–9]. To study the traveling wave solutions of a nonlinear PDE Ξ¦ (, , , , , , . . .) = 0, (1) let = βˆ’ and (, ) = (), where is the wave speed. Substituting them into (1) leads the PDE to the following ordinary differential equation: Ξ¦ 1 (, , , . . .) = 0. (2) Here, we consider the case of (2) which can be reduced to the following planar dynamical system: = = , = (, ) , (3) through integrals. Equation (3) is called the traveling wave system of the nonlinear PDE (1). So, we just study the Hindawi Publishing Corporation Mathematical Problems in Engineering Volume 2015, Article ID 610979, 19 pages http://dx.doi.org/10.1155/2015/610979

Transcript of Research Article Traveling Wave Solutions of a Generalized ...traveling wave system ( ) to get the...

  • Research ArticleTraveling Wave Solutions of a Generalized Camassa-HolmEquation: A Dynamical System Approach

    Lina Zhang and Tao Song

    Department of Mathematics, Huzhou University, Huzhou, Zhejiang 313000, China

    Correspondence should be addressed to Lina Zhang; [email protected]

    Received 1 August 2015; Accepted 14 September 2015

    Academic Editor: Maria Gandarias

    Copyright Β© 2015 L. Zhang and T. Song. This is an open access article distributed under the Creative Commons AttributionLicense, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properlycited.

    We investigate a generalized Camassa-Holm equation 𝐢(3, 2, 2): 𝑒𝑑+ π‘˜π‘’π‘₯+ 𝛾1𝑒π‘₯π‘₯𝑑

    + 𝛾2(𝑒3)π‘₯+ 𝛾3𝑒π‘₯(𝑒2)π‘₯π‘₯

    + 𝛾3𝑒(𝑒2)π‘₯π‘₯π‘₯

    = 0. Weshow that the 𝐢(3, 2, 2) equation can be reduced to a planar polynomial differential system by transformation of variables. We treatthe planar polynomial differential system by the dynamical systems theory and present a phase space analysis of their singularpoints. Two singular straight lines are found in the associated topological vector field. Moreover, the peakon, peakon-like, cuspon,smooth soliton solutions of the generalized Camassa-Holm equation under inhomogeneous boundary condition are obtained.Theparametric conditions of existence of the single peak soliton solutions are given by using the phase portrait analytical technique.Asymptotic analysis and numerical simulations are provided for single peak soliton, kink wave, and kink compacton solutions ofthe 𝐢(3, 2, 2) equation.

    1. Introduction

    Mathematical modeling of dynamical systems processing in agreat variety of natural phenomena usually leads to nonlinearpartial differential equations (PDEs).There is a special class ofsolutions for nonlinear PDEs that are of considerable interest,namely, the traveling wave solutions. Such a wave may belocalized or periodic, which propagates at constant speedwithout changing its shape.

    Many powerful methods have been presented for findingthe traveling wave solutions, such as the Bäcklund trans-formation [1], tanh-coth method [2], bilinear method [3],symbolic computation method [4], and Lie group analysismethod [5]. Furthermore, a great amount of works focusedon various extensions and applications of the methods inorder to simplify the calculation procedure. The basic ideaof those methods is that, by introducing different types ofAnsatz, the original PDEs can be transformed into a set ofalgebraic equations. Balancing the same order of the Ansatzthen yields explicit expressions for the PDE waves. However,not all of the special forms for the PDE waves can be derivedby those methods. In order to obtain all possible forms ofthe PDEwaves and analyze qualitative behaviors of solutions,

    the bifurcation theory plays a very important role in studyingthe evolution of wave patterns with variation of parameters[6–9].

    To study the traveling wave solutions of a nonlinear PDE

    Ξ¦(𝑒, 𝑒𝑑, 𝑒π‘₯, 𝑒π‘₯π‘₯, 𝑒π‘₯𝑑, 𝑒𝑑𝑑, . . .) = 0, (1)

    let πœ‰ = π‘₯ βˆ’ 𝑐𝑑 and 𝑒(π‘₯, 𝑑) = πœ‘(πœ‰), where 𝑐 is the wave speed.Substituting them into (1) leads the PDE to the followingordinary differential equation:

    Ξ¦1(πœ‘, πœ‘, πœ‘, . . .) = 0. (2)

    Here, we consider the case of (2) which can be reduced to thefollowing planar dynamical system:

    π‘‘πœ‘

    π‘‘πœ‰= πœ‘= 𝑦,

    𝑑𝑦

    π‘‘πœ‰= 𝐹 (πœ‘, 𝑦) ,

    (3)

    through integrals. Equation (3) is called the traveling wavesystem of the nonlinear PDE (1). So, we just study the

    Hindawi Publishing CorporationMathematical Problems in EngineeringVolume 2015, Article ID 610979, 19 pageshttp://dx.doi.org/10.1155/2015/610979

  • 2 Mathematical Problems in Engineering

    traveling wave system (3) to get the traveling wave solutionsof the nonlinear PDE (1).

    Let us begin with some well-known nonlinear waveequations. The first one is the Camassa-Holm (CH) equation[10]

    π‘’π‘‘βˆ’ 𝑒𝑑π‘₯π‘₯

    + 3𝑒𝑒π‘₯= 2𝑒π‘₯𝑒π‘₯π‘₯

    + 𝑒𝑒π‘₯π‘₯π‘₯

    (4)

    arising as a model for nonlinear waves in cylindrical axiallysymmetric hyperelastic rods, with 𝑒(π‘₯, 𝑑) representing theradial stretch relative to a prestressed state where Camassaand Holm showed that (4) has a peakon of the form 𝑒(π‘₯, 𝑑) =π‘π‘’βˆ’|π‘₯βˆ’π‘π‘‘|. Among the nonanalytic entities, the peakon, a

    soliton with a finite discontinuity in gradient at its crest, isperhaps the weakest nonanalyticity observable by the eye [11].

    To understand the role of nonlinear dispersion in theformation of patters in liquid drop, Rosenau and Hyman [12]introduced and studied a family of fully nonlinear dispersionKorteweg-de Vries equations

    𝑒𝑑+ (π‘’π‘š)π‘₯+ (𝑒𝑛)π‘₯π‘₯π‘₯

    = 0. (5)

    This equation, denoted by 𝐾(π‘š, 𝑛), owns the property that,for certainπ‘š and 𝑛, its solitary wave solutions have compactsupport [12]. That is, they identically vanish outside a finitecore region. For instance, the 𝐾(2, 2) equation admits thefollowing compacton solution:

    𝑒 (π‘₯, 𝑑) =

    {{

    {{

    {

    4𝑐

    3cos2 (π‘₯ βˆ’ 𝑐𝑑

    4) , |π‘₯ βˆ’ 𝑐𝑑| ≀ 2πœ‹,

    0, otherwise.(6)

    The Camassa-Holm equation, the 𝐾(2, 2) equation, andalmost all integrable dispersive equations have the sameclass of traveling wave systems which can be written in thefollowing form [13]:

    π‘‘πœ‘

    π‘‘πœ‰= 𝑦 =

    1

    𝐷2 (πœ‘)

    πœ•π»

    πœ•π‘¦,

    𝑑𝑦

    π‘‘πœ‰= βˆ’

    1

    𝐷2 (πœ‘)

    πœ•π»

    πœ•πœ‘= βˆ’

    𝐷(πœ‘) 𝑦2+ 𝑔 (πœ‘)

    𝐷2 (πœ‘),

    (7)

    where 𝐻 = 𝐻(πœ‘, 𝑦) = (1/2)𝑦2𝐷2(πœ‘) + ∫𝐷(πœ‘)𝑔(πœ‘)π‘‘πœ‘ is thefirst integral. It is easy to see that (4) is actually a special case of(3) with 𝐹(πœ‘, 𝑦) = βˆ’(1/𝐷2(πœ‘))(πœ•π»/πœ•πœ‘). If there is a functionπœ‘ = πœ‘

    𝑠such that 𝐷(πœ‘

    𝑠) = 0, then πœ‘ = πœ‘

    𝑠is a vertical straight

    line solution of the system

    π‘‘πœ‘

    π‘‘πœ= 𝑦𝐷 (πœ‘) ,

    𝑑𝑦

    π‘‘πœ= βˆ’π·(πœ‘) 𝑦2βˆ’ 𝑔 (πœ‘) ,

    (8)

    where π‘‘πœ‰ = 𝐷(πœ‘)π‘‘πœ for πœ‘ ΜΈ= πœ‘π‘ . The two systems have

    the same topological phase portraits except for the verticalstraight line πœ‘ = πœ‘

    𝑠and the directions in time. Consequently,

    we can obtain bifurcation and smooth solutions of thenonlinear PDE (1) through studying the system (8), if the

    corresponding orbits are bounded and do not intersect withthe vertical straight line πœ‘ = πœ‘

    𝑠. However, the orbits,

    which do intersect with the vertical straight line πœ‘ = πœ‘π‘ or

    are unbounded but can approach the vertical straight line,correspond to the non-smooth singular traveling waves. Itis worth of pointing out that traveling waves sometimes losetheir smoothness during the propagation due to the existenceof singular curves within the solution surfaces of the waveequation.

    Most of these works are concentrated on the nonlinearwave equationswith only a singular straight line [6–9]. But tillnow there have been few works on the integrable nonlinearequations with two singular straight lines or other types ofsingular curves [13–15].

    In 2004, Tian and Yin [16] introduced the following fullynonlinear generalized Camassa-Holm equation 𝐢(π‘š, 𝑛, 𝑝):

    𝑒𝑑+ π‘˜π‘’π‘₯+ 𝛾1𝑒π‘₯π‘₯𝑑

    + 𝛾2(π‘’π‘š)π‘₯+ 𝛾3𝑒π‘₯(𝑒𝑛)π‘₯π‘₯

    + 𝛾4𝑒 (𝑒𝑝)π‘₯π‘₯π‘₯

    = 0,

    (9)

    where π‘˜, 𝛾1, 𝛾2, 𝛾3, and 𝛾

    4are arbitrary real constants and π‘š,

    𝑛, and 𝑝 are positive integers. By using four direct ansatzs,they obtained kink compacton solutions, nonsymmetry com-pacton solutions, and solitary wave solutions for the𝐢(2, 1, 1)and 𝐢(3, 2, 2) equations.

    Generally, it is not an easy task to obtain a uniformanalytic first integral of the corresponding traveling wavesystem of (9). In this paper, we consider the cases π‘š = 3,𝑛 = 𝑝 = 2, and 𝛾

    3= 𝛾4. Then, (9) reduces to the 𝐢(3, 2, 2)

    equation

    𝑒𝑑+ π‘˜π‘’π‘₯+ 𝛾1𝑒π‘₯π‘₯𝑑

    + 𝛾2(𝑒3)π‘₯+ 𝛾3𝑒π‘₯(𝑒2)π‘₯π‘₯

    + 𝛾3𝑒 (𝑒2)π‘₯π‘₯π‘₯

    = 0.

    (10)

    Actually, we have already considered a special 𝐢(3, 2, 2)equation in [17], namely, 𝛾

    1= βˆ’1, 𝛾

    2= βˆ’3, and 𝛾

    3= βˆ’1,

    where the bifurcation of peakons are obtained by applyingthe qualitative theory of dynamical systems. In this work,a more general 𝐢(3, 2, 2) equation (10) is studied. Differentbifurcation curves are derived to divide the parameter spaceinto different regions associated with different types of phasetrajectories. Meanwhile, it is interesting to point out that thecorresponding traveling wave system of (10) has two singularstraight lines compared with (4), which therefore gives rise toa variety of nonanalytic traveling wave solutions, for instance,peakons, cuspons, compactons, kinks, and kink-compactons.

    This paper is organized as follows. In Section 2,we analyzethe bifurcation sets and phase portraits of correspondingtraveling wave system. In Section 3, we classify single peaksoliton solutions of (10) and give the parametric representa-tions of the smooth soliton solutions, peakon-like solutions,cuspon solutions, and peakon solutions. In Section 4, weobtain the kink wave and kink compacton solutions of (10).A short conclusion is given in Section 5.

  • Mathematical Problems in Engineering 3

    2. Bifurcation Sets and Phase Portraits

    In this section, we shall study all possible bifurcations andphase portraits of the vector fields defined by (10) in theparameter space. To achieve such a goal, let 𝑒(π‘₯, 𝑑) = πœ‘(πœ‰)with πœ‰ = π‘₯ βˆ’ 𝑐𝑑 be the solution of (10), then it follows that

    (π‘˜ βˆ’ 𝑐) πœ‘βˆ’ 𝛾1π‘πœ‘

    + 𝛾2(πœ‘3)

    + 𝛾3πœ‘(πœ‘2)

    + 𝛾3πœ‘ (πœ‘2)

    = 0,

    (11)

    where πœ‘ = πœ‘πœ‰, πœ‘ = πœ‘

    πœ‰πœ‰, and πœ‘ = πœ‘

    πœ‰πœ‰πœ‰. Integrating (11) once

    and setting the integration constant as 𝑔, we have

    (π‘˜ βˆ’ 𝑐) πœ‘ βˆ’ 𝛾1π‘πœ‘+ 𝛾2πœ‘3+ 𝛾3πœ‘ (πœ‘2)

    = βˆ’π‘”. (12)

    Clearly, (12) is equivalent to the planar system

    π‘‘πœ‘

    π‘‘πœ‰= 𝑦,

    𝑑𝑦

    π‘‘πœ‰=π›½πœ‘3+ πœ‘π‘¦2+ πœ–πœ‘ + 𝜎

    𝜌 βˆ’ πœ‘2,

    (13)

    where 𝜌 = 𝑐𝛾1/2𝛾3, 𝛽 = 𝛾

    2/2𝛾3, 𝜎 = 𝑔/2𝛾

    3, and πœ– = (π‘˜βˆ’π‘)/2𝛾

    3

    (𝛾3

    ΜΈ= 0). System (13) has the first integral

    𝐻(πœ‘, 𝑦) =𝛽

    4πœ‘4+1

    2πœ–πœ‘2+ πœŽπœ‘ +

    1

    2πœ‘2𝑦2βˆ’1

    2πœŒπ‘¦2= β„Ž. (14)

    Obviously, for 𝜌 > 0, system (13) is a singular travelingwave system [14]. Such a system may possess complicateddynamical behavior and thus generate many new travelingwave solutions. Hence, we assume 𝜌 > 0 in the rest of thispaper (𝜌 = 2, > 0). The phase portraits defined by thevector fields of system (13) determine all possible travelingwave solutions of (10). However, it is not convenient todirectly investigate (13) since there exist two singular straightlines πœ‘ = and πœ‘ = βˆ’ on the right-hand side of the secondequation of (13). To avoid the singular lines temporarily, wedefine a new independent variable 𝜁 by setting (π‘‘πœ‰/π‘‘πœ) =2βˆ’πœ‘2; then, system (13) is changed to a Hamiltonian system,

    written asπ‘‘πœ‘

    π‘‘πœ= (2βˆ’ πœ‘2) 𝑦,

    𝑑𝑦

    π‘‘πœ= πœ‘π‘¦2+ π›½πœ‘3+ πœ–πœ‘ + 𝜎.

    (15)

    System (15) has the same topological phase portraits as system(13) except for the singular lines πœ‘ = and πœ‘ = βˆ’.

    We now investigate the bifurcation of phase portraits ofthe system (15). Denote that

    𝑓 (πœ‘) = π›½πœ‘3+ πœ–πœ‘ + 𝜎. (16)

    Let 𝑀(πœ‘π‘’, 𝑦𝑒) be the coefficient matrix of the linearized

    system of (15) at the equilibrium point (πœ‘π‘’, 𝑦𝑒); then,

    𝑀(πœ‘π‘’, 𝑦𝑒) = (

    βˆ’2πœ‘π‘’π‘¦π‘’π‘¦2

    πœ–+ 𝑓(πœ‘π‘’)

    2βˆ’ πœ‘2

    𝑒2πœ‘π‘’π‘¦π‘’

    ) , (17)

    and at this equilibrium point, we have

    𝐽 (πœ‘π‘’, 𝑦𝑒) = det𝑀(πœ‘

    𝑒, 𝑦𝑒)

    = (πœ‘2

    π‘’βˆ’ 2) 𝑓(πœ‘π‘’) βˆ’ (3πœ‘

    2

    𝑒+ 2) 𝑦2

    𝑒.

    (18)

    By the theory of planar dynamical systems, for an equilibriumpoint of a Hamiltonian system, if 𝐽 < 0, then it is a saddlepoint, a center point if 𝐽 > 0, and a degenerate equilibriumpoint if 𝐽 = 0.

    From the above analysis, we can obtain the bifurcationcurves and phase portraits under different parameter condi-tions.

    Let

    𝛽1(𝜎) = βˆ’

    4πœ–3

    27𝜎2,

    𝛽2(𝜎) =

    𝜎 βˆ’ πœ–

    3,

    𝛽3(𝜎) =

    βˆ’πœŽ βˆ’ πœ–

    3.

    (19)

    Clearly, for 𝛽 > 𝛽1(𝜎), the function 𝑓(πœ‘) = 0 has three

    real roots πœ‘1, πœ‘2, and πœ‘

    3(πœ‘1

    > πœ‘2

    > πœ‘3); that is, system

    (15) has three equilibrium points 𝐸𝑖(πœ‘π‘–, 0), 𝑖 = 1, 2, 3 on

    the πœ‘-axis. When 𝛽 < 𝛽3(𝜎), (15) has two equilibrium

    points 𝑆1,2(, Β±π‘Œ

    1) on the straight line πœ‘ = βˆšπ‘Ž, where π‘Œ

    1=

    √(βˆ’πœŽ βˆ’ (πœ– + 𝛽2))/. When 𝛽 < 𝛽2(𝜎), system (15) has two

    equilibrium points 𝑆3,4(βˆ’, Β±π‘Œ

    2) on the straight line πœ‘ = βˆ’,

    where π‘Œ2= √(𝜎 βˆ’ (πœ– + 𝛽2))/. Notice that on making the

    transformation 𝜎 β†’ βˆ’πœŽ, πœ‘ β†’ βˆ’πœ‘, 𝜁 β†’ βˆ’πœ, system (15)is invariant. This means that, for 𝜎 < 0, the phase portraitsof (15) are just the reflections of the corresponding phaseportraits of (15) in the case 𝜎 > 0 with respect to the 𝑦-axis.Thus, we only need to consider the case 𝜎 β‰₯ 0. To knowthe dynamical behavior of the orbits of system (15), we willdiscuss two cases: πœ– > 0 and πœ– < 0.

    2.1. Case I: πœ– > 0

    Lemma 1. Suppose that πœ– > 0. Denote β„Ž+= 𝐻(, Β±π‘Œ

    1), β„Žβˆ’=

    𝐻(βˆ’, Β±π‘Œ2), and β„Ž

    𝑖= 𝐻(πœ‘

    𝑖, 0), 𝑖 = 1, 2, 3.

    (1) For 𝜎 > 0 and 𝛽1(𝜎) < 𝛽 < 𝛽

    3(𝜎), there exists one

    and only one curve 𝛽 = 𝛽4(𝜎) on the (𝜎, 𝛽)-plane on which

    β„Ž+

    = β„Ž2; for 𝜎 > 0 and 𝛽

    1(𝜎) < 𝛽 < 𝛽

    2(𝜎), there exists one

    and only one curve 𝛽 = 𝛽5(𝜎) on the (𝜎, 𝛽)-plane on which

    β„Žβˆ’

    = β„Ž2or β„Žβˆ’= β„Ž3.Moreover, the curves𝛽 = 𝛽

    1(𝜎),𝛽 = 𝛽

    2(𝜎),

    𝛽 = 𝛽4(𝜎), and 𝛽 = 𝛽

    5(𝜎) are tangent at the point (𝜎

    1𝑠, 𝛽1𝑠).

    The curve 𝛽 = 𝛽3(𝜎) intersects with the curves 𝛽 = 𝛽

    1(𝜎),

    𝛽 = 𝛽4(𝜎), and 𝛽 = 𝛽

    5(𝜎) at the points (𝜎

    2𝑠, 𝛽2𝑠), (𝜎3𝑠, 𝛽3𝑠),

    and (𝜎4𝑠, 𝛽4𝑠) (0 < 𝜎

    4𝑠< 𝜎3𝑠< 𝜎2𝑠< 𝜎1𝑠), respectively.

    (2) For 𝜎 = 0, there exists a bifurcation point 𝐴(0, βˆ’2πœ–/2)on (𝜎, 𝛽)-plane on which β„Ž+

    = β„Žβˆ’

    = β„Ž2when 𝛽 = βˆ’2πœ–/2,

    β„Ž+

    = β„Žβˆ’

    < β„Ž2when 𝛽 < βˆ’2πœ–/2, and β„Ž+

    = β„Žβˆ’

    > β„Ž2when

    βˆ’2πœ–/2< 𝛽 < βˆ’πœ–/

    2.

  • 4 Mathematical Problems in Engineering

    𝛽2(𝜎)

    (𝜎1s, 𝛽1s)

    𝛽3(𝜎)

    𝛽4(𝜎)𝛽5(𝜎)

    𝛽

    βˆ’2

    βˆ’2

    βˆ’4

    βˆ’4

    βˆ’6

    βˆ’8

    βˆ’10

    βˆ’12

    βˆ’14

    𝛽1(𝜎)

    𝜎2 4

    Figure 1: The bifurcation curves in the (𝜎, 𝛽)-parameter plane forπœ– > 0.

    According to the above analysis and Lemma 1, we obtainthe following proposition on the bifurcation curves of thephase portraits of system (15) for πœ– > 0.

    Proposition 2. When πœ– > 0, for system (15), in (𝜎, 𝛽)-parameter plane, there exist five bifurcation curves (see Fig-ure 1):

    𝛽 = 𝛽1(𝜎) = βˆ’

    4πœ–3

    27𝜎2,

    𝛽 = 𝛽2(𝜎) =

    𝜎 βˆ’ πœ–

    3,

    𝛽 = 𝛽3(𝜎) =

    βˆ’πœŽ βˆ’ πœ–

    3,

    𝛽 = 𝛽4(𝜎) (|𝜎| ≀ 𝜎

    3𝑠) ,

    𝛽 = 𝛽5(𝜎) .

    (20)

    These five curves divide the right-half (𝜎, 𝛽)-parameter planeinto thirty-one regions as follows:

    𝐴1: {(𝜎, 𝛽) | 𝜎1s < 𝜎 < πœ–, 𝛽 = 𝛽2(𝜎)},

    𝐴2: {(𝜎, 𝛽) | 𝜎 > 𝜎1s, 𝛽5(𝜎) < 𝛽 < 𝛽2(𝜎)},

    𝐴3: {(𝜎, b) | 𝜎 > 𝜎1s, 𝛽 = 𝛽5(𝜎)},

    𝐴4: {(𝜎, 𝛽) | 𝜎 > 𝜎1s, 𝛽1(𝜎) < 𝛽 < 𝛽5(𝜎)},

    𝐴5: {(𝜎, 𝛽) | 𝜎 > 𝜎1s, 𝛽 = 𝛽1(𝜎)},

    𝐴6: {(𝜎, 𝛽) | 𝜎 > 𝜎2s, 𝛽3(𝜎) < 𝛽 < 𝛽1(𝜎)},

    𝐴7: {(𝜎, 𝛽) | 𝜎 < 𝜎2s, 𝛽 = 𝛽3(𝜎)},

    𝐴8: {(𝜎, 𝛽) | 𝜎 > 0, 𝛽 < max{𝛽1(𝜎), 𝛽3(𝜎)}},

    𝐴9: (𝜎, 𝛽) = (𝜎2s, 𝛽2s),

    𝐴10: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎2s, 𝛽 = 𝛽1(𝜎)},

    𝐴11: {(𝜎, 𝛽) | 𝜎 < 𝜎2s, 𝛽1(𝜎) < 𝛽 < min{𝛽3(𝜎),

    𝛽4(𝜎)}},

    𝐴12: {(𝜎, 𝛽) | 𝜎 < 𝜎3s, 𝛽 = 𝛽4(𝜎)},

    𝐴13: {(𝜎, 𝛽) | 𝜎 > 0, 𝛽4(𝜎) < 𝛽 < 𝛽5(𝜎)},

    𝐴14: {(𝜎, 𝛽) | 𝜎 < 𝜎4s, 𝛽 = 𝛽5(𝜎)},

    𝐴15: {(𝜎, 𝛽) | 𝜎 > 0, 𝛽5(𝜎) < 𝛽 < 𝛽3(𝜎)},

    𝐴16: {(𝜎, 𝛽) | 𝜎 = 0, 𝛽 < βˆ’2πœ–/2},

    𝐴17: (𝜎, 𝛽) = (0, βˆ’2πœ–/2),

    𝐴18: {(𝜎, 𝛽) | 𝜎 = 0, βˆ’2πœ–/2 < 𝛽 < βˆ’πœ–/2},

    𝐴19: (𝜎, 𝛽) = (0, βˆ’πœ–/2),

    𝐴20: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎4s, 𝛽 = 𝛽3(𝜎)},

    𝐴21: (𝜎, 𝛽) = (𝜎4s, 𝛽4s),

    𝐴22: {(𝜎, 𝛽) | 𝜎4s < 𝜎 < 𝜎2s, 𝛽 = 𝛽3(𝜎)},

    𝐴23: {(𝜎, 𝛽) | 𝜎4s < 𝜎 < 𝜎1s, max{𝛽1(𝜎), 𝛽3(𝜎)} <

    𝛽 < 𝛽5(𝜎)},𝐴24: {(𝜎, 𝛽) | 𝜎

    s4 < 𝜎 < 𝜎1s, 𝛽 = 𝛽5(𝜎)},

    𝐴25: {(𝜎, 𝛽) | 𝜎4s < 𝜎 < 𝜎1s, max{𝛽3(𝜎), 𝛽5(𝜎)} <

    𝛽 < 𝛽2(𝜎)},𝐴26: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎1s, 𝛽 = 𝛽2(d)},

    𝐴27: (𝜎, 𝛽) = (𝜎1s, 𝛽1s),

    𝐴28: {(𝜎, 𝛽) | 0 ≀ 𝜎 < πœ–, 𝛽 > 𝛽2(𝜎)},

    𝐴29: {(𝜎, 𝛽) | 𝜎 ∈ R, 𝛽 > max{0, 𝛽2(𝜎)}},

    𝐴30: {(𝜎, 𝛽) | 𝜎 > πœ–, 𝛽 = 𝛽2(𝜎)},

    𝐴31: {(𝜎, 𝛽) | 𝜎 > πœ–, 0 < 𝛽 < 𝛽2(𝜎)}.

    In this case, the phase portraits of system (15) can beshown in Figure 2.

    2.2. Case II: πœ– < 0. In this case, we have the following.

    Proposition 3. When πœ– < 0, for system (15), in (𝜎, 𝛽)-parameter plane, there exist four parametric bifurcation curves(see Figure 3):

    𝛽 = 𝛽1(𝜎) = βˆ’

    4πœ–3

    27𝜎2,

    𝛽 = 𝛽2(𝜎) =

    𝜎 βˆ’ πœ–

    3,

    𝛽 = 𝛽3(𝜎) =

    βˆ’πœŽ βˆ’ πœ–

    3, 𝜎 = 0.

    (21)

    These four curves divide the right-half (𝜎, 𝛽)-parameter planeinto twenty-two regions:

    𝐡1: {(𝜎, 𝛽) | 𝜎1s < 𝜎 < πœ–, 𝛽 = 𝛽3(𝜎)},

    𝐡2: {(𝜎, 𝛽) | 𝜎 > 𝜎1s, max{0, 𝛽3(𝜎)} < 𝛽 < 𝛽1(𝜎)},

    𝐡3: {(𝜎, 𝛽) | 𝜎 > 𝜎1s, 𝛽 = 𝛽1(𝜎)},

    𝐡4: {(𝜎, 𝛽) | 𝜎 > 𝜎2s, 𝛽1(𝜎) < 𝛽 < 𝛽2(𝜎)},

    𝐡5: (𝜎, 𝛽) = (𝜎2s, 𝛽2s),

    𝐡6: {(𝜎, 𝛽) | 𝜎 > 𝜎2s, 𝛽 = 𝛽2(𝜎)},

    𝐡7: {(𝜎, 𝛽) | 𝜎 > 0, 𝛽 > max{𝛽1(𝜎), 𝛽2(𝜎)}},

    𝐡8: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎2s, 𝛽 = 𝛽1(𝜎)},

    𝐡9: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎2s, 𝛽2(𝜎) < 𝛽 < 𝛽1(𝜎)},

    𝐡10: {(𝜎, 𝛽) | 𝜎 = 0, 𝛽 > βˆ’πœ–/2},

  • Mathematical Problems in Engineering 5

    0 1 2 3

    0

    2

    4

    0 2 4

    0

    2

    4

    0 2 4

    0

    2

    4

    0 2 4

    0

    2

    4

    0 2 4

    0

    2

    4

    0 1

    0

    2

    4

    0.0 0.5 1.0

    0

    2

    4

    0.0 0.5 1.0

    0

    2

    4

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    2

    4

    6

    0.0 0.5 1.0

    0

    2

    4

    0.0 0.5 1.0

    0

    2

    4

    βˆ’3

    βˆ’3

    βˆ’2 βˆ’2 βˆ’2βˆ’1βˆ’4

    βˆ’4

    βˆ’2 βˆ’2

    βˆ’2

    βˆ’1

    βˆ’1

    βˆ’4βˆ’2βˆ’4

    βˆ’4 βˆ’4

    βˆ’2 βˆ’2 βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5 βˆ’1.0 βˆ’0.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5 βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’6

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘ πœ‘

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘ πœ‘

    yy

    y

    y yy

    yyy

    y

    y y

    (1) (𝜎, 𝛽) ∈ A1

    (4) (𝜎, 𝛽) ∈ A4

    (7) (𝜎, 𝛽) ∈ A7 (8) (𝜎, 𝛽) ∈ A8 (9) (𝜎, 𝛽) ∈ A9

    (5) (𝜎, 𝛽) ∈ A5

    (2) (𝜎, 𝛽) ∈ A2 (3) (𝜎, 𝛽) ∈ A3

    (6) (𝜎, 𝛽) ∈ A6

    (10) (𝜎, 𝛽) ∈ A10 (11) (𝜎, 𝛽) ∈ A11 (12) (𝜎, 𝛽) ∈ A12

    Figure 2: Continued.

  • 6 Mathematical Problems in Engineering

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    2

    4

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    0.0 0.5 1.0

    0

    1

    2

    0.0 0.5 1.0

    0

    1

    2

    0.0 0.5 1.0

    0

    1

    2

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    3

    βˆ’3

    βˆ’2

    βˆ’1

    βˆ’3

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’3

    βˆ’2

    βˆ’1

    βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5

    βˆ’1.0βˆ’1.5 βˆ’0.5 βˆ’1.0βˆ’1.5 βˆ’0.5

    βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5 βˆ’1.0 βˆ’0.5

    βˆ’1.0 βˆ’0.5 βˆ’1.0 βˆ’0.5

    βˆ’2

    βˆ’4

    y

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘ πœ‘

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘πœ‘

    yy

    y yy

    yy

    y

    yy

    y

    (13) (𝜎, 𝛽) ∈ A13

    (16) (𝜎, 𝛽) ∈ A16

    (19) (𝜎, 𝛽) ∈ A19 (20) (𝜎, 𝛽) ∈ A20

    (23) (𝜎, 𝛽) ∈ A23 (24) (𝜎, 𝛽) ∈ A24

    (21) (𝜎, 𝛽) ∈ A21

    (22) (𝜎, 𝛽) ∈ A22

    (17) (𝜎, 𝛽) ∈ A17 (18) (𝜎, 𝛽) ∈ A18

    (14) (𝜎, 𝛽) ∈ A14 (15) (𝜎, 𝛽) ∈ A15

    Figure 2: Continued.

  • Mathematical Problems in Engineering 7

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0 1 2

    0

    1

    2

    3

    0 1 2

    0

    1

    2

    3

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0 1 2

    0

    2

    4

    0 1 2

    0

    2

    4

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’2

    βˆ’4

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2 βˆ’1

    βˆ’2βˆ’3 βˆ’1

    βˆ’2

    βˆ’2

    βˆ’3

    βˆ’4

    βˆ’1

    βˆ’2 βˆ’1

    βˆ’1.0βˆ’1.5 βˆ’0.5 βˆ’1.0βˆ’1.5 βˆ’0.5

    βˆ’1.0βˆ’1.5 βˆ’0.5

    y

    yyy

    y y y

    πœ‘

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘ πœ‘

    (25) (𝜎, 𝛽) ∈ A25

    (28) (𝜎, 𝛽) ∈ A28 (29) (𝜎, 𝛽) ∈ A29

    (31) (𝜎, 𝛽) ∈ A31

    (30) (𝜎, 𝛽) ∈ A30

    (26) (𝜎, 𝛽) ∈ A26 (27) (𝜎, 𝛽) ∈ A27

    Figure 2: The bifurcation of phase portraits of system (15) when πœ– > 0 and 𝜎 β‰₯ 0.

    𝐡11: (𝜎, 𝛽) = (0, βˆ’πœ–/2),

    𝐡12: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎2s, 𝛽 = 𝛽2(𝜎)},

    𝐡13: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎1s, 𝛽3(𝜎) < 𝛽 < min{𝛽1(𝜎),

    𝛽2(𝜎)}},

    𝐡14: {(𝜎, 𝛽) | 𝜎4s < 𝜎 < 𝜎1s, 𝛽 = 𝛽1(𝜎)},

    𝐡15: (𝜎, 𝛽) = (𝜎1s, 𝛽1s),

    𝐡16: {(𝜎, 𝛽) | 0 < 𝜎 < 𝜎1s, 𝛽 = 𝛽3(𝜎)},

    𝐡17: {(𝜎, 𝛽) | 0 < 𝜎 < πœ–, 𝛽 < 𝛽3(𝜎)},

    𝐡18: {(𝜎, 𝛽) | 𝜎 = 0, 𝛽 = βˆ’πœ–/2},

    𝐡19: {(𝜎, 𝛽) | 𝜎 = 0, 𝛽 < 0},

    𝐡20: {(𝜎, 𝛽) | 0 < 𝜎 < πœ–, 𝛽 < min{0, 𝛽3(𝜎)}},

    𝐡21: {(𝜎, 𝛽) | 𝜎 > πœ–, 𝛽 = 𝛽3(𝜎)},

    𝐡22: {(𝜎, 𝛽) | 𝜎 > πœ–, 𝛽3(𝜎) < 𝛽 < 0}.

    Based on Proposition 3, we obtain the phase portraits ofsystem (15) which are shown in Figure 4.

  • 8 Mathematical Problems in Engineering

    2 4 6

    5

    10

    15

    𝛽2(𝜎)

    (𝜎1s, 𝛽1s)

    (𝜎2s, 𝛽2s)

    𝛽3(𝜎)

    𝛽

    βˆ’2βˆ’4βˆ’6

    𝛽1(𝜎)

    𝜎

    Figure 3: The bifurcation curves in the (𝜎, 𝛽)-parameter plane forπœ– < 0.

    3. Single Peak Soliton Solutions

    In this section, we study classification of single peak solitonsolutions of (10) by using the phase portraits given inSection 2. LetπΆπ‘˜(Ξ©) denote the set of all π‘˜ times continuouslydifferentiable functions on the open setΞ©. 𝐿𝑝loc(R) refer to theset of all functions whose restriction on any compact subsetis 𝐿𝑝 integrable.𝐻1loc(R) stands for𝐻

    1

    loc(R) = {πœ‘ ∈ 𝐿2

    loc(R) |

    πœ‘βˆˆ 𝐿2

    loc(R)}.To study single peak soliton solutions, we impose the

    boundary condition

    limπœ‰β†’Β±βˆž

    πœ‘ = 𝐴, (22)

    where 𝐴 is a constant. In fact, the constant 𝐴 is equal to thehorizontal coordinate of saddle point 𝐸(πœ‘

    𝑒, 0). Substituting

    the boundary condition (22) into (14) generates the followingconstant:

    β„Ž = 𝐴(𝜎 +π΄πœ–

    2+𝐴3𝛽

    4) . (23)

    So the ODE (14) becomes

    (πœ‘)2

    =

    (πœ‘ βˆ’ 𝐴)2

    (π›½πœ‘2+ 2π΄π›½πœ‘ + 3𝐴

    2𝛽 + 2πœ–)

    2 (2 βˆ’ πœ‘2). (24)

    If 𝛽(𝐴2𝛽 + πœ–) ≀ 0, then (24) reduces to

    (πœ‘)2

    =𝛽 (πœ‘ βˆ’ 𝐴)

    2

    (πœ‘ βˆ’ 𝐡1) (πœ‘ βˆ’ 𝐡

    2)

    2 (2 βˆ’ πœ‘2), (25)

    where

    𝐡1= βˆ’π΄ βˆ’

    βˆšβˆ’2𝛽 (𝐴2𝛽 + πœ–)

    𝛽,

    𝐡2= βˆ’π΄ +

    βˆšβˆ’2𝛽 (𝐴2𝛽 + πœ–)

    𝛽.

    (26)

    From (26) we know that 𝐡1> 𝐡2if 𝛽 < 0 and 𝐡

    1< 𝐡2if

    𝛽 > 0.

    Definition 4. A functionπœ‘(πœ‰) is said to be a single peak solitonsolution for the 𝐢(3, 2, 2) equation (10) if πœ‘(πœ‰) satisfies thefollowing conditions:

    (C1) πœ‘(πœ‰) is continuous on R and has a unique peakpoint πœ‰

    0, where πœ‘(πœ‰) attains its global maximum or

    minimum value.

    (C2) πœ‘(πœ‰) ∈ 𝐢3(R βˆ’ {πœ‰

    0}) satisfies (24) on R βˆ’ {πœ‰

    0}.

    (C3) πœ‘(πœ‰) satisfies the boundary condition (22).

    Definition 5. A wave function πœ‘ is called smooth solitonsolution if πœ‘ is smooth locally on either side of πœ‰

    0and

    limπœ‰β†‘πœ‰0

    πœ‘(πœ‰) = lim

    πœ‰β†“πœ‰0πœ‘(πœ‰) = 0.

    Definition 6. A wave function πœ‘ is called peakon if πœ‘ issmooth locally on either side of πœ‰

    0and lim

    πœ‰β†‘πœ‰0πœ‘(πœ‰) =

    βˆ’limπœ‰β†“πœ‰0

    πœ‘(πœ‰) = π‘Ž, π‘Ž ΜΈ= 0, π‘Ž ΜΈ= ±∞.

    Definition 7. Awave functionπœ‘ is called cuspon ifπœ‘ is smoothlocally on either side of πœ‰

    0and lim

    πœ‰β†‘πœ‰0πœ‘(πœ‰) = βˆ’lim

    πœ‰β†“πœ‰0πœ‘(πœ‰) =

    ±∞.

    Without any loss of generality, we choose the peak pointπœ‰0as vanishing, πœ‰

    0= 0.

    Theorem 8. Assume that 𝑒(π‘₯, 𝑑) = πœ‘(πœ‰) = πœ‘(π‘₯ βˆ’ 𝑐𝑑) is a singlepeak soliton solution of the 𝐢(3, 2, 2) equation (10) at the peakpoint πœ‰

    0= 0. Then, we have the following:

    (i) If 𝛽(𝐴2𝛽 + πœ–) > 0, then πœ‘(0) = or πœ‘(0) = βˆ’.

    (ii) If 𝛽(𝐴2𝛽 + πœ–) ≀ 0, then πœ‘(0) = or πœ‘(0) = βˆ’ orπœ‘(0) = 𝐡

    1or πœ‘(0) = 𝐡

    2.

    Proof. If πœ‘(0) ΜΈ= Β±, then πœ‘(πœ‰) ΜΈ= Β± for any πœ‰ ∈ R sinceπœ‘(πœ‰) ∈ 𝐢

    3(R βˆ’ {0}). Differentiating both sides of (24) yields

    πœ‘ ∈ 𝐢∞(R).

    (i) When 𝛽(𝐴2𝛽 + πœ–) > 0, if πœ‘(0) ΜΈ= and πœ‘(0) ΜΈ= βˆ’, thenπœ‘ ∈ 𝐢

    ∞(R). By the definition of single peak soliton we have

    πœ‘(0) = 0. However, by (24) we must have πœ‘(0) = 𝐴, which

    contradicts the fact that 0 is the unique peak point.(ii) When 𝛽(𝐴2𝛽 + πœ–) ≀ 0, if πœ‘(0) ΜΈ= and πœ‘(0) ΜΈ= βˆ’,

    by (24) we know πœ‘(0) exists and πœ‘(0) = 0 since 0 is a peakpoint. Thus, we obtain πœ‘(0) = 𝐡

    1or πœ‘(0) = 𝐡

    2from (25),

    since πœ‘(0) = 𝐴 contradicts the fact that 0 is the unique peakpoint.

    Now we give the following theorem on the classificationof single peak solitons of (10).The idea is inspired by the studyof the traveling waves of Camassa-Holm equation [18, 19].

    Theorem 9. Assume that 𝑒(π‘₯, 𝑑) = πœ‘(π‘₯ βˆ’ 𝑐𝑑) is a single peaksoliton solution of the 𝐢(3, 2, 2) equation (10) at the peak pointπœ‰0= 0. Then, we have the following solution classification:(i) If |πœ‘(0)| ΜΈ= , then πœ‘(πœ‰) ∈ 𝐢∞(R), and πœ‘ is a smooth

    soliton solution.

  • Mathematical Problems in Engineering 9

    0 2

    0

    2

    4

    0 2

    0

    2

    4

    0 1 2

    0

    2

    4

    0 1 2

    0

    2

    4

    0.0 0.5 1.0 1.5

    0

    2

    4

    0 1

    0

    2

    4

    6

    0.0 0.5 1.0 1.5

    0

    2

    4

    0.0 0.5 1.0

    0

    1

    2

    3

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0.0 0.5 1.0

    0

    1

    2

    0.0 0.5 1.0 1.5

    0

    1

    2

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    βˆ’3 βˆ’1βˆ’4

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2βˆ’4

    βˆ’6

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’2 βˆ’4 βˆ’4βˆ’2 βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’1βˆ’2 βˆ’1βˆ’2

    πœ‘

    πœ‘

    πœ‘

    πœ‘ πœ‘πœ‘

    πœ‘ πœ‘

    πœ‘ πœ‘

    πœ‘ πœ‘

    y

    y

    y

    yy

    y

    y y

    y y

    y y

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5βˆ’2.0 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5 βˆ’1.5 βˆ’1.0 βˆ’0.5βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5βˆ’1.0 βˆ’0.5

    (10) (𝜎, 𝛽) ∈ B10 (11) (𝜎, 𝛽) ∈ B11 (12) (𝜎, 𝛽) ∈ B12

    (1) (𝜎, 𝛽) ∈ B1

    (4) (𝜎, 𝛽) ∈ B4

    (7) (𝜎, 𝛽) ∈ B7 (8) (𝜎, 𝛽) ∈ B8 (9) (𝜎, 𝛽) ∈ B9

    (5) (𝜎, 𝛽) ∈ B5 (6) (𝜎, 𝛽) ∈ B6

    (2) (𝜎, 𝛽) ∈ B2 (3) (𝜎, 𝛽) ∈ B3

    Figure 4: Continued.

  • 10 Mathematical Problems in Engineering

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0 1

    0

    1

    2

    3

    0 1 2

    0

    2

    4

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0 1 2

    0

    1

    2

    3

    0.0 0.5 1.0 1.5

    0

    1

    2

    0.0 0.5 1.0 1.5

    0

    1

    2

    3

    0 1 2

    0

    1

    2

    3

    0.0 0.5 1.0 1.5

    0

    2

    4

    0.0 0.5 1.0 1.5

    0

    2

    4

    6

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’2

    βˆ’4

    βˆ’6

    βˆ’2

    βˆ’3 βˆ’1βˆ’2

    βˆ’3 βˆ’1βˆ’2

    βˆ’1βˆ’2

    βˆ’1βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    βˆ’1

    βˆ’2

    βˆ’3

    βˆ’1

    βˆ’2

    πœ‘ πœ‘ πœ‘

    πœ‘πœ‘πœ‘

    πœ‘ πœ‘πœ‘

    πœ‘

    y y y

    yy

    y

    y yy

    y

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5βˆ’2.0 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    βˆ’1.5 βˆ’1.0 βˆ’0.5

    (13) (𝜎, 𝛽) ∈ B13 (14) (𝜎, 𝛽) ∈ B14 (15) (𝜎, 𝛽) ∈ B15

    (16) (𝜎, 𝛽) ∈ B16 (17) (𝜎, 𝛽) ∈ B17 (18) (𝜎, 𝛽) ∈ B18

    (22) (𝜎, 𝛽) ∈ B22

    (20) (𝜎, 𝛽) ∈ B20 (21) (𝜎, 𝛽) ∈ B21(19) (𝜎, 𝛽) ∈ B19

    Figure 4: The bifurcation of phase portraits of system (15) when πœ– < 0 and 𝜎 β‰₯ 0.

  • Mathematical Problems in Engineering 11

    (ii) If πœ‘(0) = ΜΈ= 𝐡1, then πœ‘ is a cuspon solution and πœ‘ has

    the following asymptotic behavior:

    πœ‘ (πœ‰) βˆ’ = πœ†1

    πœ‰

    2/3

    + 𝑂(πœ‰

    4/3

    ) , πœ‰ β†’ 0,

    πœ‘(πœ‰) =

    2

    3πœ†1

    πœ‰

    βˆ’1/3 sgn (πœ‰) + 𝑂 (πœ‰

    1/3

    ) ,

    πœ‰ β†’ 0,

    (27)

    where πœ†1= Β±(9|𝛽

    2+ 2𝐴𝛽 + 3𝐴

    2𝛽 + 2πœ–|( βˆ’ 𝐴)

    2/16)1/3.

    Thus, πœ‘(πœ‰) βˆ‰ 𝐻1π‘™π‘œπ‘(R).

    (iii) If πœ‘(0) = βˆ’ ΜΈ= 𝐡2, then πœ‘ is a cuspon solution and πœ‘

    has the following asymptotic behavior:

    πœ‘ (πœ‰) + = πœ†2

    πœ‰

    2/3

    + 𝑂(πœ‰

    4/3

    ) , πœ‰ β†’ 0,

    πœ‘(πœ‰) =

    2

    3πœ†2

    πœ‰

    βˆ’1/3 sgn (πœ‰) + 𝑂 (πœ‰

    1/3

    ) ,

    πœ‰ β†’ 0,

    (28)

    where πœ†2= Β±(9|𝛽

    2βˆ’ 2𝐴𝛽 + 3𝐴

    2𝛽 + 2πœ–|( + 𝐴)

    2/16)1/3.

    Thus, πœ‘(πœ‰) βˆ‰ 𝐻1π‘™π‘œπ‘(R).

    (iv) If πœ‘(0) = = 𝐡1and 𝐴 ΜΈ= 0, then πœ‘ is a peakon-like

    solution and

    πœ‘ (πœ‰) βˆ’ = πœ†3

    πœ‰ + 𝑂 (

    πœ‰

    2

    ) , πœ‰ β†’ 0,

    πœ‘(πœ‰) = πœ†

    3sgn (πœ‰) + 𝑂 (πœ‰

    ) , πœ‰ β†’ 0,

    (29)

    where πœ†3= Β±|𝐴 βˆ’ |βˆšπ›½(𝐡

    2βˆ’ )/4.

    (v) If πœ‘(0) = βˆ’ = 𝐡2and 𝐴 ΜΈ= 0, then πœ‘ is a peakon-like

    solution and

    πœ‘ (πœ‰) + = πœ†4

    πœ‰ + 𝑂 (

    πœ‰

    2

    ) , πœ‰ β†’ 0,

    πœ‘(πœ‰) = πœ†

    4sgn (πœ‰) + 𝑂 (πœ‰

    ) , πœ‰ β†’ 0,

    (30)

    where πœ†4= Β±|𝐴 + |βˆšβˆ’π›½(𝐡

    1+ )/4.

    (vi) If πœ‘(0) = = 𝐡1and 𝐴 = 0, then πœ‘ gives the peakon

    solution exp(βˆ’βˆšβˆ’π›½/2|π‘₯ βˆ’ 𝑐𝑑|).(vii) If πœ‘(0) = βˆ’ = 𝐡

    2and 𝐴 = 0, then πœ‘ gives the peakon

    solution βˆ’ exp(βˆ’βˆšβˆ’π›½/2|π‘₯ βˆ’ 𝑐𝑑|).

    Proof. (vi) and (vii) are obvious. Let us prove (i), (ii), and (iv)in order.

    (i) From the process of proofing of Theorem 8, we knowthat if |πœ‘(0)| ΜΈ= , then πœ‘ ∈ 𝐢∞(R) and πœ‘ is a smooth solitonsolution.

    (ii) If πœ‘(0) = ΜΈ= 𝐡1, then by the definition of single peak

    soliton we have 𝐴 ΜΈ= ; thus, π›½πœ‘2 + 2π΄π›½πœ‘ + 3𝐴2𝛽 + 2πœ– doesnot contain the factor πœ‘ βˆ’ . From (24), we obtain

    πœ‘= sgn (𝐴 βˆ’ )

    πœ‘ βˆ’ 𝐴

    √2πœ‘2 βˆ’ 2

    β‹… βˆšπ›½πœ‘2 + 2π΄π›½πœ‘ + 3𝐴2𝛽 + 2πœ–

    sgn (πœ‰) .

    (31)

    Let 𝑙1(πœ‘) = √2(πœ‘ + )/|πœ‘ βˆ’ 𝐴|√|π›½πœ‘2 + 2π΄π›½πœ‘ + 3𝐴2𝛽 + 2πœ–|;

    then, 𝑙1() = 2√/| βˆ’ 𝐴|√|𝛽

    2 + 2𝐴𝛽 + 3𝐴2𝛽 + 2πœ–|, and

    ∫ 𝑙1(πœ‘)√

    πœ‘ βˆ’ π‘‘πœ‘ = ∫ sgn (𝐴 βˆ’ ) sgn (πœ‰) π‘‘πœ‰. (32)

    Inserting 𝑙1(πœ‘) = 𝑙

    1() + 𝑂(|πœ‘ βˆ’ |) into (32) and using the

    initial condition πœ‘(0) = , we obtain

    2𝑙1()

    3

    πœ‘ βˆ’

    3/2

    (1 + 𝑂 (πœ‘ βˆ’

    )) =πœ‰ ;

    (33)

    thus,

    πœ‘ βˆ’ = Β±(3

    2𝑙1()

    )

    2/3

    πœ‰

    2/3

    (1 + 𝑂 (πœ‘ βˆ’

    ))βˆ’2/3

    = Β±(3

    2𝑙1()

    )

    2/3

    πœ‰

    2/3

    (1 + 𝑂 (πœ‘ βˆ’

    )) ,

    (34)

    which implies πœ‘ βˆ’ = 𝑂(|πœ‰|2/3). Therefore, we have

    πœ‘ (πœ‰) = Β± (3

    2𝑙1()

    )

    2/3

    πœ‰

    2/3

    + 𝑂(πœ‰

    4/3

    )

    = + πœ†1

    πœ‰

    2/3

    + 𝑂(πœ‰

    4/3

    ) , πœ‰ β†’ 0,

    πœ†1= Β±(

    3

    2𝑙1()

    )

    2/3

    = Β±(

    9𝛽2+ 2𝐴𝛽 + 3𝐴

    2𝛽 + 2πœ–

    ( βˆ’ 𝐴)

    2

    16)

    1/3

    ,

    πœ‘(πœ‰) =

    2

    3πœ†1

    πœ‰

    βˆ’1/3 sgn (πœ‰) + 𝑂 (πœ‰

    1/3

    ) , πœ‰ β†’ 0.

    (35)

    So, πœ‘(πœ‰) βˆ‰ 𝐻1loc(R).(iii) Similar to the proof of (ii), we ignore it in this paper.(iv) If πœ‘(0) = = 𝐡

    1and 𝐴 ̸= 0, then from (25) we obtain

    πœ‘= βˆšβˆ’

    𝛽

    2sgn (𝐴 βˆ’ ) πœ‘ βˆ’ 𝐴

    βˆšπœ‘ βˆ’ 𝐡2

    πœ‘ + sgn (πœ‰) . (36)

    Let 𝑙2(πœ‘) = (1/|πœ‘βˆ’π΄|)√(πœ‘ + )/(πœ‘ βˆ’ 𝐡

    2); then, 𝑙

    2() = (1/|βˆ’

    𝐴|)√2/( βˆ’ 𝐡2) and

    ∫ 𝑙2(πœ‘) π‘‘πœ‘ = βˆšβˆ’

    𝛽

    2∫ sgn (𝐴 βˆ’ ) sgn (πœ‰) π‘‘πœ‰. (37)

    Inserting 𝑙2(πœ‘) = 𝑙

    2() + 𝑂(|πœ‘ βˆ’ |) into (37) and using the

    initial condition πœ‘(0) = , we obtain

    𝑙2() (πœ‘ βˆ’ ) (1 + 𝑂 (

    πœ‘ βˆ’ ))βˆ’1

    = sgn (𝐴 βˆ’ ) πœ‰ .

    (38)

    Sincesgn (πœ‘ βˆ’ ) sgn (𝐴 βˆ’ ) β‰₯ 0,

    1

    1 + 𝑂 (πœ‘ βˆ’ )= 1 + 𝑂 (πœ‘ βˆ’ ) ,

    (39)

  • 12 Mathematical Problems in Engineering

    we get

    πœ‘ βˆ’ =

    βˆšβˆ’π›½

    2

    1

    𝑙2()

    πœ‰ (1 + 𝑂 (πœ‘ βˆ’ )) ,

    (40)

    which implies |πœ‘ βˆ’ | = 𝑂(|πœ‰|). Therefore, we have

    πœ‘ (πœ‰) = + πœ†3

    πœ‰ + 𝑂 (

    πœ‰

    2

    ) , πœ‰ β†’ 0,

    πœ‘(πœ‰) = πœ†

    3sgn (πœ‰) + 𝑂 (πœ‰

    ) , πœ‰ β†’ 0,

    (41)

    where πœ†3= Β±|𝐴 βˆ’ |βˆšπ›½(𝐡

    2βˆ’ )/4.

    (v) Similar to the proof of (iv), we ignore it in this paper.

    By virtue of Theorem 9, any single peak soliton for the𝐢(3, 2, 2) equation (10) must satisfy the following initial andboundary values problem:

    (πœ‘)2

    =𝛽 (πœ‘ βˆ’ 𝐴)

    2

    (πœ‘ βˆ’ 𝐡1) (πœ‘ βˆ’ 𝐡

    2)

    2 (2 βˆ’ πœ‘2)fl𝐿 (πœ‘) ,

    πœ‘ (0) ∈ {, βˆ’, 𝐡1, 𝐡2} ,

    lim|πœ‰|β†’βˆž

    πœ‘ (πœ‰) = 𝐴.

    (42)

    𝐿(πœ‘) β‰₯ 0 and the boundary condition (24) imply thefollowing:

    (a) If 𝛽(2 βˆ’ πœ‘2) β‰₯ 0, then πœ‘ β‰₯ max{𝐡1, 𝐡2} or πœ‘ ≀

    min{𝐡1, 𝐡2}.

    (b) If𝛽(2βˆ’πœ‘2) ≀ 0, thenmin{𝐡1, 𝐡2} ≀ πœ‘ ≀ max{𝐡

    1, 𝐡2}.

    Below, we will present some implicit formulas for thesingle peak soliton solutions in the case of specific 𝜎 and 𝛽.

    Case 1 ((𝜎, 𝛽) ∈ 𝐴12). In this case, we have βˆ’ < 𝐡

    2< 𝐴 <

    𝐡1= . From the standard phase analysis and Theorem 9

    we know that if πœ‘ is a single peak soliton of the 𝐢(3, 2, 2)equation, then

    πœ‘= βˆ’βˆšβˆ’

    𝛽

    2(πœ‘ βˆ’ 𝐴)√

    πœ‘ βˆ’ 𝐡2

    πœ‘ + sgn (πœ‰) . (43)

    From the separation of variables we get

    βˆ«β„Ž (πœ‘) π‘‘πœ‘ = βˆšβˆ’π›½

    2sgn (πœ‰) π‘‘πœ‰, (44)

    where β„Ž(πœ‘) = (1/(𝐴 βˆ’ πœ‘))√(πœ‘ + )/(πœ‘ βˆ’ 𝐡2). After a lengthy

    calculation of integral, we obtain the implicit solution πœ‘defined by

    𝐻(πœ‘)fl√𝐴 +

    𝐴 βˆ’ 𝐡2

    𝐼1(πœ‘) βˆ’ 𝐼

    2(πœ‘) = βˆšβˆ’

    𝛽

    2

    πœ‰ + 𝐾,

    (45)

    where

    𝐼1(πœ‘) = ln

    (𝐴 + ) (πœ‘ βˆ’ 𝐡2) + (𝐴 βˆ’ 𝐡

    2) (πœ‘ + ) + 2√(𝐴 + ) (𝐴 βˆ’ 𝐡

    2) (πœ‘ βˆ’ 𝐡

    2) (πœ‘ + )

    √(𝐴 + ) (𝐴 βˆ’ 𝐡2) (𝐴 + ) (𝐴 βˆ’ πœ‘)

    ,

    𝐼2(πœ‘) = ln

    (πœ‘ + ) + (πœ‘ βˆ’ 𝐡

    2) + 2√(πœ‘ + ) (πœ‘ βˆ’ 𝐡

    2)

    ,

    (46)

    and 𝐾 is an arbitrary integration constant. For πœ‘(0) = , theconstant𝐾 = 𝐻(πœ‘(0)) is defined by

    𝐾 = √𝐴 +

    𝐴 βˆ’ 𝐡2

    𝐼1() βˆ’ 𝐼

    2() , (47)

    and for πœ‘(0) = 𝐡2,

    𝐾 = √𝐴 +

    𝐴 βˆ’ 𝐡2

    𝐼1(𝐡2) βˆ’ 𝐼2(𝐡2) . (48)

    (i) If πœ‘(0) = , then 𝐴 < πœ‘ ≀ . Since 𝐻(πœ‘) = β„Ž(πœ‘), weknow that𝐻(πœ‘) strictly decreases on the interval (𝐴, ]; thus,𝐻1(πœ‘) = 𝐻|

    (𝐴,](πœ‘) gives a single peak solitonwith𝐻

    1() = 𝐾

    and𝐻1(𝐴+) = ∞. Therefore, πœ‘

    1(πœ‰) = 𝐻

    βˆ’1

    1(βˆšβˆ’π›½/2|πœ‰| + 𝐾) is

    the solution satisfying

    πœ‘1(0) = ,

    lim|πœ‰|β†’βˆž

    πœ‘1(πœ‰) = 𝐴,

    πœ‘

    1(0Β±) = Β± (𝐴 βˆ’ )√

    𝛽 (𝐡2βˆ’ )

    4.

    (49)

    So, πœ‘1(πœ‰) is a peakon-like solution (see Figure 5).

    (ii) If πœ‘(0) = 𝐡2, then 𝐡

    2≀ πœ‘ < 𝐴. By 𝐻(πœ‘) = 𝑓(πœ‘),

    we know that 𝐻(πœ‘) strictly increases on the interval [𝐡2, 𝐴).

    Thus,

    𝐻2(πœ‘) = 𝐻|

    [𝐡2 ,𝐴)(πœ‘) (50)

  • Mathematical Problems in Engineering 13

    βˆ’3 βˆ’2 βˆ’1

    πœ‘

    βˆ’0.2

    1 2 3

    0.2

    0.4

    0.6

    0.8

    1.0

    x

    (a)

    02

    02

    βˆ’2 βˆ’2 x

    1.0

    0.5

    0.0

    t

    πœ‘

    22

    (b)

    Figure 5: Two- and three-dimensional graphs of the peakon-like solution.

    βˆ’0.3

    βˆ’0.4

    βˆ’0.5

    1 2 3βˆ’3 βˆ’2 βˆ’1

    πœ‘

    βˆ’0.2

    x

    (a)

    0

    2

    0

    2

    βˆ’2βˆ’2

    βˆ’0.2

    βˆ’0.3

    βˆ’0.4

    βˆ’0.5

    βˆ’0.6

    t x

    πœ‘

    0

    2

    0

    2

    βˆ’2βˆ’2

    t x

    (b)

    Figure 6: Two- and three-dimensional graphs of the smooth soliton solution.

    has the inverse denoted by πœ‘2(πœ‰) = 𝐻

    βˆ’1

    2(βˆšβˆ’π›½/2|πœ‰| + 𝐾).

    πœ‘2(πœ‰) gives a kind of smooth soliton solution (see Figure 6)

    satisfying

    πœ‘2(0) = 𝐡

    2,

    lim|πœ‰|β†’βˆž

    πœ‘2(πœ‰) = 𝐴,

    πœ‘

    2(0) = 0.

    (51)

    Case 2 ((𝜎, 𝛽) ∈ 𝐴14). In this case, we have βˆ’ = 𝐡

    2< 𝐴 <

    < 𝐡1and (25) is equivalent to

    πœ‘= βˆ’βˆšβˆ’

    𝛽

    2(πœ‘ βˆ’ 𝐴)√

    πœ‘ βˆ’ 𝐡1

    πœ‘ βˆ’ sgn (πœ‰) . (52)

    Let

    𝑔 (πœ‘) =1

    𝐴 βˆ’ πœ‘βˆšπœ‘ βˆ’ 𝐡1

    πœ‘ βˆ’ ; (53)

  • 14 Mathematical Problems in Engineering

    βˆ’1 1 2 3

    0.2

    0.4

    0.6

    0.8

    1.0

    βˆ’3 βˆ’2

    πœ‘

    x

    (a)

    02

    02βˆ’2

    βˆ’2

    πœ‘

    x t

    0.0

    0.5

    1.0

    (b)

    Figure 7: Two- and three-dimensional graphs of the cuspon solution.

    then, (52) is converted to

    𝑔 (πœ‘) π‘‘πœ‘ =1

    𝐴 βˆ’ πœ‘βˆšπœ‘ βˆ’ 𝐡1

    πœ‘ βˆ’ π‘‘πœ‘ = βˆšβˆ’

    𝛽

    2sgn (πœ‰) π‘‘πœ‰. (54)

    Integrating (54) on the interval [0, πœ‰] (or [πœ‰, 0]) leads to thefollowing implicit solutions:

    𝐺 (πœ‘)fl√𝐴 βˆ’

    𝐴 βˆ’ 𝐡1

    𝐼3(πœ‘) + 𝐼

    4(πœ‘) = βˆšβˆ’

    𝛽

    2

    πœ‰ + 𝐾,

    (55)

    where

    𝐼3(πœ‘) = ln

    (𝐴 βˆ’ ) (πœ‘ βˆ’ 𝐡1) + (𝐴 βˆ’ 𝐡

    1) (πœ‘ βˆ’ ) + 2√(𝐴 βˆ’ ) (𝐴 βˆ’ 𝐡

    1) (πœ‘ βˆ’ ) (πœ‘ βˆ’ 𝐡

    1)

    √(𝐴 βˆ’ ) (𝐴 βˆ’ 𝐡1) (𝐴 βˆ’ ) (πœ‘ βˆ’ 𝐴)

    ,

    𝐼4(πœ‘) = ln

    (πœ‘ βˆ’ ) + (πœ‘ βˆ’ 𝐡

    1) + 2√(πœ‘ βˆ’ ) (πœ‘ βˆ’ 𝐡

    1)

    .

    (56)

    And𝐾 is an arbitrary integration constant. It is obvious that,for πœ‘(0) = , the constant𝐾 = 𝐻(πœ‘(0)) is defined by

    𝐾 = √𝐴 βˆ’

    𝐴 βˆ’ 𝐡1

    𝐼3() + 𝐼

    4() , (57)

    and for πœ‘(0) = βˆ’,

    𝐾 = √𝐴 βˆ’

    𝐴 βˆ’ 𝐡1

    𝐼3(βˆ’) + 𝐼

    4(βˆ’) . (58)

    (i) If πœ‘(0) = , then 𝐴 < πœ‘ ≀ . From 𝑔(πœ‘) < 0, weknow that 𝐺(πœ‘) strictly decreases on the interval (𝐴, ] with𝐺() = 𝐾 and 𝐺(𝐴+) = ∞. Define

    𝐺1(πœ‘) = 𝐺|

    (𝐴,](πœ‘) . (59)

    Since 𝐺1(πœ‘) is a strictly decreasing function from (𝐴, ] onto

    [𝐾,∞), we can solve for πœ‘ uniquely from (59) and obtain

    πœ‘1(πœ‰) = 𝐺

    βˆ’1

    1(βˆšβˆ’

    𝛽

    2

    πœ‰ + 𝐾) .

    (60)

    It is easy to check that πœ‘ satisfies

    πœ‘1(0) = ,

    lim|πœ‰|β†’βˆž

    πœ‘1(πœ‰) = 𝐴,

    πœ‘

    1(0Β±) = βˆ“βˆž.

    (61)

    Therefore, the solutionπœ‘1defined by (60) is a cuspon solution

    for the 𝐢(3, 2, 2) equation (see Figure 7).

  • Mathematical Problems in Engineering 15

    (ii) If πœ‘(0) = βˆ’, then βˆ’ ≀ πœ‘ < 𝐴. Through a similaranalysis, we get a strictly increasing function 𝐺(πœ‘) on theinterval [βˆ’, 𝐴) satisfying

    𝐺 (πœ‘) = βˆšβˆ’π›½

    2

    πœ‰ + 𝐾,

    (62)

    where 𝐺(πœ‘) is defined by (55). Let

    𝐺2(πœ‘) = 𝐺|

    [βˆ’,𝐴)(πœ‘) , (63)

    then 𝐺2(πœ‘) is a strictly increasing function from [βˆ’, 𝐴) onto

    [𝐾,∞) so that we can solve for πœ‘ and obtain

    πœ‘2(πœ‰) = 𝐺

    βˆ’1

    2(βˆšβˆ’

    𝛽

    2

    πœ‰ + 𝐾) .

    (64)

    It is easy to check that πœ‘2satisfies

    πœ‘2(0) = βˆ’,

    lim|πœ‰|β†’βˆž

    πœ‘2(πœ‰) = 𝐴,

    πœ‘

    2(0Β±) = Β± (𝐴 + )βˆšβˆ’

    𝛽 (𝐡1+ )

    4.

    (65)

    Therefore, the solution πœ‘2defined by (64) is a peakon-like

    solution, whose graph is similar to those in Figure 5.

    Case 3 ((𝜎, 𝛽) ∈ 𝐴16). In this case, we have βˆ’ < 𝐡

    2< 𝐴 =

    0 < 𝐡1< , 𝐡

    2= βˆ’π΅1, and

    πœ‘= βˆ’βˆšβˆ’

    𝛽

    2πœ‘βˆš

    πœ‘ βˆ’ 𝐡2

    1

    πœ‘2 βˆ’ 2sgn (πœ‰) . (66)

    Hence from the separation of variables we have

    √2 βˆ’ πœ‘2

    πœ‘βˆšπ΅2

    1βˆ’ πœ‘2

    π‘‘πœ‘ = βˆ’βˆšβˆ’π›½

    2sgn (πœ‰) π‘‘πœ‰. (67)

    Integrating (67) on the interval [0, πœ‰] (or [πœ‰, 0]) leads tothe following implicit formula for the two smooth solitonsolutions:

    √2 βˆ’ πœ‘2 + √𝐡2

    1βˆ’ πœ‘2

    √2 βˆ’ 𝐡2

    1

    (

    √(2 βˆ’ 𝐡2

    1) πœ‘2

    √𝐡2

    1βˆ’ πœ‘2 + 𝐡

    1√2 βˆ’ πœ‘2

    )

    = exp(βˆ’βˆšβˆ’π›½

    2|π‘₯ βˆ’ 𝑐𝑑|) ,

    (68)

    where πœ‘ ∈ (𝐴, 𝐡1]. Consider

    √2 βˆ’ 𝐡2

    2

    √2 βˆ’ πœ‘2 + √𝐡2

    2βˆ’ πœ‘2

    (

    √𝐡2

    2βˆ’ πœ‘2 βˆ’ 𝐡

    2√2 βˆ’ πœ‘2

    √(2 βˆ’ 𝐡2

    2) πœ‘2

    )

    = exp(βˆšβˆ’π›½

    2|π‘₯ βˆ’ 𝑐𝑑|) ,

    (69)

    where πœ‘ ∈ [𝐡2, 𝐴).

    Case 4 ((𝜎, 𝛽) ∈ 𝐴17). In this case, we have βˆ’ = 𝐡

    2< 𝐴 =

    0 < 𝐡1= , and

    πœ‘= βˆ’βˆšβˆ’

    𝛽

    2πœ‘ sgn (πœ‰) . (70)

    Choosing πœ‘(0) = (or βˆ’) as initial value, we get

    ∫

    πœ‘

    1

    πœ‘π‘‘πœ‘ = βˆ’βˆ«

    πœ‰

    0

    βˆšβˆ’π›½

    2sgn (πœ‰) π‘‘πœ‰, for 𝐴 < πœ‘ ≀ ,

    ∫

    πœ‘

    βˆ’

    1

    πœ‘π‘‘πœ‘ = βˆ’βˆ«

    πœ‰

    0

    βˆšβˆ’π›½

    2sgn (πœ‰) π‘‘πœ‰, for βˆ’ ≀ πœ‘ < 𝐴,

    (71)

    which immediately yield the peakon solutions

    πœ‘ (π‘₯ βˆ’ 𝑐𝑑) = Β± exp(βˆ’βˆšβˆ’π›½

    2|π‘₯ βˆ’ 𝑐𝑑|) . (72)

    The graphs for the peakon solution (72) are shown in Figure 8.

    Remark 10. The classical peakon solution (72) and peakon-like solution (64) admit left-half derivative and right-halfderivative at their crest. But the signs of the left-half derivativeand right-half derivative are opposite, so the peakon andpeakon-like solutions admit the discontinuous first orderderivative at their crest. In comparison with classical peakonsolution (72), the expression of the peakon-like solution (64)is more complex. Moreover, by observing Figures 2(14) and2(17) we find that the phase orbits of the peakon consist ofthree straight lines, but the phase orbits of the peakon-likeconsist of two curves and a straight line. Therefore, we callthe soliton solution (64) the peakon-like solution.

    4. Kink Wave and Kink Compacton Solutions

    We now turn our attention to the kink wave solutions of the𝐢(3, 2, 2) equation (10). In order to study kinkwave solutions,we assume that

    limπœ‰β†’βˆž

    πœ‘ (πœ‰) = 𝐴1,

    limπœ‰β†’βˆ’βˆž

    πœ‘ (πœ‰) = 𝐴2,

    (73)

  • 16 Mathematical Problems in Engineering

    2 4

    0.2

    0.4

    0.6

    0.8

    1.0

    βˆ’2βˆ’4

    πœ‘

    x

    (a)

    0 2

    02

    0.0

    0.5

    1.0

    βˆ’2

    πœ‘

    x

    t

    0

    2

    βˆ’2

    (b)

    Figure 8: Two- and three-dimensional graphs of the peakon solution.

    where 𝐴1> 𝐴2. Substituting the boundary condition (73)

    into (14) generates

    (πœ‘)2

    =

    𝛽 (πœ‘ βˆ’ 𝐴1) (πœ‘ βˆ’ 𝐴

    2) [πœ‘2+ (𝐴1+ 𝐴2) πœ‘ + 𝐴

    2

    1+ 𝐴1𝐴2+ 𝐴2

    2+ 2πœ–/𝛽]

    2 (2 βˆ’ πœ‘2)fl𝐹 (πœ‘) . (74)

    The nonlinear differential equation (74) may sustaindifferent kinds of nonlinear excitations. In what follows, weconfine our attention to the cases 𝐴

    2= βˆ’π΄

    1and πœ– =

    βˆ’π΄2

    1𝛽 which describe kinks and kink compactons which

    play an important role in the dynamics systems. Under theseconsiderations, (74) reduces to

    (πœ‘)2

    =𝛽 (πœ‘ βˆ’ 𝐴

    1)2

    (πœ‘ βˆ’ 𝐴2)2

    2 (2 βˆ’ πœ‘2). (75)

    If 𝐴1< , then from the phase analysis in Section 2 (see

    Figure 4(10)), we know that (𝐴1, 0) and (𝐴

    2, 0) are two saddle

    points of (13) and the kink solutions can be obtained fromthe two heteroclinic orbits connecting (πœ™, 𝑦) = (𝐴

    1, 0) and

    (𝐴2, 0). When 𝐴

    1increases upon reaching , that is 𝐴

    1= ,

    (75) becomes

    (πœ‘)2

    = βˆ’π›½ (πœ‘ βˆ’ 𝐴

    1) (πœ‘ βˆ’ 𝐴

    2)

    2, (76)

    and the ellipse 2𝑦2+𝛽(πœ‘βˆ’π΄1)(πœ‘βˆ’π΄

    2) = 0 (see Figure 4(11)),

    which is tangent to the singular lines πœ‘ = and πœ‘ = βˆ’ atpoints (𝐴

    1, 0) and (𝐴

    2, 0), respectively, gives rise to two kink

    compactons of (10).We next explore the qualitative behavior of kink wave

    solutions to (75) and (76). If πœ‘ is a kink wave solutions of (75)

    or (76), we have πœ‘ β†’ 0 as πœ‘ β†’ 𝐴1and as πœ‘ β†’ 𝐴

    2.

    Moreover, we have 𝐹(πœ‘) β‰₯ 0 for 𝐴2≀ πœ‘ ≀ 𝐴

    1and πœ‘ is

    strictly monotonic in any interval where 𝐹(πœ‘) > 0. Thus, ifπœ‘> 0 at some points, πœ‘will be strictly increasing until it gets

    close to the next zero of 𝐹. Denoting this zero 𝐴1, we have

    πœ‘ ↑ 𝐴1. What will happen to the solution when it approaches

    𝐴1? Depending on whether the zero is double or simple, πœ‘

    has a different behavior. We explore the two cases in turn.

    Theorem 11. (i) If πœ‘ has a simple zero at πœ‘ = 𝐴1, so that

    𝐹(𝐴1) = 0 and 𝐹(𝐴

    1) < 0, then the solution πœ‘ of (75) satisfies

    πœ‘ (πœ‰) βˆ’ 𝐴1=𝐹(𝐴1)

    4(πœ‰ βˆ’ πœ‚)

    2

    + 𝑂 ((πœ‰ βˆ’ πœ‚)4

    )

    π‘Žπ‘  πœ‰ ↑ πœ‚,

    (77)

    where πœ‘(πœ‚) = 𝐴1.

    (ii) When πœ‘ approaches the double zero 𝐴1of 𝐹(πœ‘) so that

    𝐹(𝐴1) = 0 and𝐹(𝐴

    1) > 0, then the solutionπœ‘ of (75) satisfies

    πœ‘ (πœ‰) βˆ’ 𝐴1∼ 𝛼 exp(βˆ’πœ‰βˆšπΉ (𝐴

    1)) π‘Žπ‘  πœ‰ β†’ ∞ (78)

    for some constant 𝛼. Thus, πœ‘ ↑ 𝐴1exponentially as πœ‰ β†’ ∞.

  • Mathematical Problems in Engineering 17

    Proof. (i) When 𝐴1= βˆ’π΄

    2= and πœ– = βˆ’π΄2

    1𝛽, from (76),

    𝐹(πœ‘) has a simple zero at πœ‘ = 𝐴1. Then,

    (πœ‘)2

    = (πœ‘ βˆ’ 𝐴1) 𝐹(𝐴1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)2

    )

    as πœ‘ ↑ 𝐴1.

    (79)

    Using the fact that (πœ‘)2 β‰₯ 0, we know that 𝐹(𝐴1) < 0.

    Moreover,

    π‘‘πœ‰

    π‘‘πœ‘=

    1

    √(πœ‘ βˆ’ 𝐴1) 𝐹 (𝐴

    1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)2

    )

    . (80)

    Because

    √(πœ‘ βˆ’ 𝐴1) 𝐹 (𝐴

    1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)2

    )

    = √𝐴1βˆ’ πœ‘(βˆšβˆ’πΉ (𝐴

    1) + 𝑂 (𝐴

    1βˆ’ πœ‘)) ,

    1

    βˆšβˆ’πΉ (𝐴1) + 𝑂 (𝐴

    1βˆ’ πœ‘)

    =1

    βˆšβˆ’πΉ (𝐴1)

    + 𝑂 (𝐴1βˆ’ πœ‘) ,

    (81)

    we obtainπ‘‘πœ‰

    π‘‘πœ‘=

    1

    βˆšβˆ’ (𝐴1βˆ’ πœ‘) 𝐹 (𝐴

    1)

    + 𝑂 ((𝐴1βˆ’ πœ‘)1/2

    ) . (82)

    Integrating (82) yields

    πœ‚ βˆ’ πœ‰ =2

    βˆšβˆ’πΉ (𝐴1)

    (𝐴1βˆ’ πœ‘)1/2

    + 𝑂((𝐴1βˆ’ πœ‘)3/2

    ) , (83)

    where πœ‚ satisfies πœ‘(πœ‚) = 𝐴1. Thus,

    (πœ‚ βˆ’ πœ‰)2

    =4

    βˆ’πΉ (𝐴1)(𝐴1βˆ’ πœ‘) + 𝑂 ((𝐴

    1βˆ’ πœ‘)2

    ) , (84)

    which implies 𝑂((𝐴1βˆ’ πœ‘)2) = 𝑂((πœ‚ βˆ’ πœ‰)

    4). Therefore, we get

    πœ‘ (πœ‰) = 𝐴1+𝐹(𝐴1)

    4(πœ‰ βˆ’ πœ‚)

    2

    + 𝑂 ((πœ‰ βˆ’ πœ‚)4

    )

    as πœ‰ ↑ πœ‚,(85)

    where πœ‘(πœ‚) = 𝐴1.

    (ii) When 𝐴1= βˆ’π΄

    2< and πœ– = βˆ’π΄2

    1𝛽, from (75), 𝐹(πœ‘)

    has a double zero at πœ‘ = 𝐴1. Then,

    (πœ‘)2

    = (πœ‘ βˆ’ 𝐴1)2

    𝐹(𝐴1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)3

    )

    as πœ‘ ↑ 𝐴1.

    (86)

    Furthermore, we get

    π‘‘πœ‰

    π‘‘πœ‘=

    1

    √(πœ‘ βˆ’ 𝐴1)2

    𝐹 (𝐴1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)3

    )

    . (87)

    Observing that

    √(πœ‘ βˆ’ 𝐴1)2

    𝐹 (𝐴1) + 𝑂 ((πœ‘ βˆ’ 𝐴

    1)3

    )

    = (𝐴1βˆ’ πœ‘) (√𝐹 (𝐴

    1) + 𝑂 (𝐴

    1βˆ’ πœ‘)) ,

    1

    √𝐹 (𝐴1) + 𝑂 (𝐴

    1βˆ’ πœ‘)

    =1

    √𝐹 (𝐴1)

    + 𝑂 (𝐴1βˆ’ πœ‘) ,

    (88)

    we obtainπ‘‘πœ‰

    π‘‘πœ‘=

    1

    (𝐴1βˆ’ πœ‘) 𝐹 (𝐴

    1)+ 𝑂 (1) . (89)

    By a similar computation as the one that leads to (85), wearrive at (78). This completes the proof of Theorem 11.

    Next we try to find the exact formulas for the kink wavesolutions. Let 𝐴

    1= βˆ’π΄

    2< and πœ– = βˆ’π΄2

    1𝛽. Then, (75)

    becomes

    √2 βˆ’ πœ‘2

    πœ‘2 βˆ’ 𝐴2

    1

    π‘‘πœ‘ = βˆ“βˆšπ›½

    2π‘‘πœ‰. (90)

    Integrating both sides of (90) gives the following implicitexpressions of kink and antikink wave solutions:

    arctanπœ‘

    √2 βˆ’ πœ‘2

    +

    √2 βˆ’ 𝐴2

    1

    𝐴1

    arctanh√2 βˆ’ 𝐴

    2

    1

    𝐴1

    πœ‘

    √2 βˆ’ πœ‘2

    = Β±βˆšπ›½

    2πœ‰.

    (91)

    By letting 𝐴1β†’ in (91), we get two kink compactons

    which are given by

    Β±πœ‘ =

    {{{{{{{{{

    {{{{{{{{{

    {

    sinβˆšπ›½

    2πœ‰,

    πœ‰ ≀

    πœ‹

    √2𝛽,

    , πœ‰ >πœ‹

    √2𝛽,

    βˆ’, πœ‰ < βˆ’πœ‹

    √2𝛽.

    (92)

    The graphs for the kink wave solutions (91) and kinkcompacton solutions (92) are shown in Figures 9 and 10,respectively.

    Remark 12. The two kink compacton solutions (92) aredifferent from the well-known smooth kink wave solutions.In comparison with kink wave solutions (91), the kink com-pacton solutions (92) have no exponential decay propertiesbut have compact support.That is, they minus a constant, thedifferences identically vanish outside a finite core region.

  • 18 Mathematical Problems in Engineering

    πœ‘

    πœ‰βˆ’1 1

    0.5

    βˆ’0.5

    (a)

    βˆ’1βˆ’1

    βˆ’0.5

    0.5

    0.0πœ‘

    x t

    0

    1

    01

    11

    (b)

    Figure 9: Two- and three-dimensional graphs of the kink wave solution.

    1

    1πœ‘

    πœ‰

    βˆ’1

    βˆ’1

    (a)

    0

    1

    0

    1

    0.00.51.0

    πœ‘

    βˆ’1 βˆ’1

    βˆ’0.5

    βˆ’1.0

    tx

    0

    1

    0

    1

    (b)

    Figure 10: Two- and three-dimensional graphs of the kink compacton solution.

    5. Conclusion

    In this paper, we investigate the travelingwave solutions of the𝐢(3, 2, 2) equation (10). We show that (10) can be reduced toa planar polynomial differential system by transformation ofvariables. We treat the planar polynomial differential systemby the dynamical systems theory and present a phase spaceanalysis of their singular points. Two singular straight linesare found in the associated topological vector field. Theinfluence of parameters as well as the singular lines onthe smoothness property of the traveling wave solutions isexplored in detail.

    Because any traveling wave solution of (10) is determinedfrom Newton’s equation which we write in the form 𝑦2 =𝐹(πœ‘), where 𝑦 = πœ‘

    πœ‰(πœ‰), we solve Newton’s equation 𝑦2 =

    𝐹(πœ‘) for single peak soliton solutions and kink wave andkink compacton solutions. We classify all single peak solitonsolutions of (10). Then peakon, peakon-like, cuspon, smoothsoliton solutions of the generalized Camassa-Holm equation

    (10) are obtained. The parametric conditions of existenceof the single peak soliton solutions are given by using thephase portrait analytical technique. Asymptotic analysis andnumerical simulations are provided for single peak solitonand kink wave and kink compacton solutions of the𝐢(3, 2, 2)equation.

    Actually, for π‘š = 2π‘˜ + 1, π‘˜ ∈ N+ in 𝐢(π‘š, 2, 2) equation(9), the dynamical behavior of traveling wave solutions of(9) is similar to the case π‘š = 3; for π‘š = 2π‘˜, π‘˜ ∈ N+ in𝐢(π‘š, 2, 2) equation (9), the dynamical behavior of travelingwave solutions of (9) is similar to the case π‘š = 2. We areapplying the approach mentioned in this work to 𝐢(2, 2, 2)equation (9) and already get some new solutions, which wewill report in another paper.

    Conflict of Interests

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

  • Mathematical Problems in Engineering 19

    Acknowledgments

    This work was partially supported by the National NaturalScience Foundation of China (no. 11326131 and no. 61473332)andZhejiangProvincialNatural Science Foundation ofChinaunder Grant nos. LQ14A010009 and LY13A010005.

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