Research Article Explicit Solutions to the (3+1)-Dimensional Kudryashov-Sinelshchikov Equations in Bubbly Flow Dynamics Y. B. Chukkol , M. N. B. Mohamad, and Mukhiddin Muminov Department of Mathematical Sciences, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia Correspondence should be addressed to Y. B. Chukkol; bcyusuf2@live.utm.my Received 26 August 2018; Accepted 2 October 2018; Published 1 November 2018 Academic Editor: Mehmet Sezer Copyright © 2018 Y. B. Chukkol et al. Tis 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. A modifed tanh-coth method with Riccati equation is used to construct several explicit solutions of (3+1)-dimensional Kudryashov-Sinelshchikov equations in bubble gas liquid fow. Te solutions include solitons and periodic solutions. Te method applied can be used in further works to obtain entirely new solutions to many other nonlinear evolution equations. 1. Introduction Many complex phenomena in nature are describe in various scientifc and industrial felds and especially in areas of physics such as fuid mechanics [1], optical fbres [2], plasma physics [3], and so on. Nonlinear evolution equations are used to describe these nonlinear phenomena, and that has led to the development of methods to look for exact solutions of nonlinear partial diferential equations [4]. Recently, Kudryashov and Sinelshchikov [5] developed a (3+1)-dimensional nonlinear evolution equation in a model of wave propagation in bubbly fuid fow. Te model equation has gained a lot of attention where B ˜ A¤cklund transformation and conservation laws [6], bifurcation [7], and density- fuctuation [8] analysis were carried out the important evo- lution equation. Many methods have been developed to fnd the explicit solutions of nonlinear evolution equations; example of such methods are the frst integral method [9], Jacobi elliptic function method [10], Hirota bilinear method [11], Wron- skian determinant technique [12], F-expansion method [13], Darboux Transformations [14], Backlund transformation method [6], Miura transformation [15], homotopy pertur- bation method [16], and Adomian decomposition method [17]. Many algebraic methods were proposed so far, such as tanh method which was proposed by Malfie [18]. Fan [19] extended the tanh method and obtained new exact solution that cannot be obtained by using the conventional tanh method. Further extension called tanh-coth was proposed by Wazwaz [4] which provides a wider applicability for solving nonlinear evolution equations. A modifcation was also proposed by El-Wakil [20] and Soliman [21, 22]. In this paper, we present two equations (3+1)-dimen- sional Kudryashov and Sinelshchikov equation written as ( + +  ) +  +  =0, ( + −  +  ) +  + z =0 (1) where , , and represent the nonlinearity, dissipation dispersion terms, while and stand for transverse variation of wave in and directions; we assume all the coefcient to be constant parameters. We shall use modifed tanh-coth to obtain many explicit exact solutions for (3+1)-dimensional Kudryashov-Sinelshchikov equations. Te travelling wave solution of a special case of (1) is given in [7]. Note that when =0, (1) reduces to their two-dimensional counterparts ( + +  ) +  =0, ( + −  +  ) +  =0, (2) which were widely studied in [16, 17, 23, 24]. Furthermore when ==0, (1) reduces to one-dimensional Korteweg- de-Vries equations (KdV) and one-dimensional Korteweg- de-Vries-Burgers equations (KdVB). Tese equations have many applications in fuid dynamics [25], plasma physics Hindawi Journal of Applied Mathematics Volume 2018, Article ID 7452786, 9 pages https://doi.org/10.1155/2018/7452786