ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)


For citation:

Zemlyanukhin A. I., Bochkarev A. V. Continued fractions, the perturbation method and exact solutions to nonlinear evolution equations. Izvestiya VUZ. Applied Nonlinear Dynamics, 2016, vol. 24, iss. 4, pp. 71-85. DOI: 10.18500/0869-6632-2016-24-4-71-85

This is an open access article distributed under the terms of Creative Commons Attribution 4.0 International License (CC-BY 4.0).
Full text PDF(Ru):
(downloads: 92)
Language: 
English
Article type: 
Article
UDC: 
517.98.537

Continued fractions, the perturbation method and exact solutions to nonlinear evolution equations

Autors: 
Zemlyanukhin Aleksandr Isaevich, Yuri Gagarin State Technical University of Saratov
Bochkarev Andrej Vladimirovich, Yuri Gagarin State Technical University of Saratov
Abstract: 

A new method is proposed in which constructing exact solutions to nonlinear evolution equations is based on successive applying the perturbation method and apparatus of the continued fractions. It is shown that exact solitary-wave solutions arise in the limiting case as the sum of geometric series of the perturbation method based on the linearized problem. It is demonstrated that the continued fraction corresponding to the perturbation series, terminates to a convergent giving an expression for the desired exact soliton-like solution. The order of the convergent is established to be not less than twice the pole order of the original equation’s solution. The effectiveness of the method is demonstrated on the solution of integrable 5th order equation of the Korteweg–de Vries family, 3rd order equation with 5 arbitrary constants, the Calogero–Degasperis–Fokas equation and the non-integrable Kuramoto–Sivashinsky equation. The analysis showed that in the case of integrable equations the continued fraction corresponding to the perturbation series terminates unconditionally, that is, the series is geometric or becomes so after regrouping the terms. For non-integrable equations the requirement of termination of the continued fraction that is equivalent to the geometricity of the perturbation series leads to the conditions on the original equation coefficients, which are necessary for the existence of exact soliton-like solutions. The advantages of the method, which can be easily implemented using any of the computer mathematics systems, include the ability to work with equations, the solution of which has a pole of zero, fractional or higher natural order.

Reference: 
  1. Hirota R. Exact solution of the Korteweg–de Vries equation for multiple collisions of solitons // Phys. Rev. Lett. 1971. Vol. 27. Pp. 1192–1194.
  2. Baker G.A.Jr., Graves-Morris P. Pade Approximants, Cambridge: Cambridge U.P., 1996.
  3. Manevitch L.I. Linear and nonlinear mathematical physics: from harmonic waves to solitons // Soros. Obrazov. Journ. 1996. N1. Pp. 86–93 (Russian).
  4. Jones W.B., Thron W.J. Continued fractions: analytic theory and applications. Reading, MA: Addison-Wesley, 1980.
  5. Zemlyanukhin A.I., Bochkarev A.V. The perturbation method and exact solutions of nonlinear dynamics equations for media with microstructure // Computational Continuum Mechanics. 2016. Vol. 9, N2. Pp. 182–191 (Russian).
  6. Lambert F. and Musette M. Solitary waves, padeons and solitons // Lect. Notes Math. 1984. Vol. 1071. Pp. 197–212.
  7. Lambert F., Musette M. Solitons from a direct point of view: padeons // J. Comp. Appl. Math. 1986. Vol. 15. Pp. 235–249.
  8. Baikov V.A., Khusnutdinova K.R. Formal linearization and exact solutions of some nonlinear partial differential equations // J. Nonlin. Math. Phys. 1996. N3. Pp. 139–146.
  9. Bender C.M., Milton K.A. Continued fraction as a discrete nonlinear transform // J. Math. Phys. 1994. Vol. 35, N1. Pp. 364–367.
  10. Cohen H. Numerical Approximation Methods. New York: Springer-Verlag, 2011.
  11. Khovansky A.N. Applications of continued fractions and their generalization to problems in approximation theory. Groningen: P. Noordhoff N.V., 1963.
  12. Meshkov A.G., Sokolov V.V. Integrable evolution equations with the constant separant// Ufa Math. J. 2012. Vol. 4, N3. Pp. 104–153.
  13. Encyclopedia of Integrable Systems / A.B. Shabat, V.E. Adler, V.G. Marikhin, V.V. Sokolov (Eds.), L.D. Landau Institute for Theoretical Physics – Research Institute for Symbolic Computations, J. Kepler Universit at, 2007.
  14. Gandarias M.L., Saez S. Traveling-wave solutions of the Calogero–Degasperis–Fokas equation in 2+1 dimensions // Theor. Math. Phys. 2005. Vol. 144, N1. Pp. 916–926.
  15. Ryabov P.N. Exact solutions of the Kudryashov–Sinelshchikov equation // Appl. Math. Comput. 2010. Vol. 217, N7. Pp. 3585–3590.
  16. The Painlev’ Property: One Century Later / R. Conte (Ed.). New York: Springer, 1999.
  17. Kudryashov N.A. Methods of nonlinear mathematical physics. Dolgoprudnyj: Izd. Dom Intellekt, 2010.
Received: 
26.06.2016
Accepted: 
31.08.2016
Published: 
31.08.2016
Short text (in English):
(downloads: 96)