The paper concerns capillary-gravity surface waves propagating on a two-dimensional incompressible and inviscid fluid with or without an obstacle placed at flat horizontal bottom. Formally second-order correct model equations, analogous to the first-order KdV equation, are derived under classical assumptions of long wavelength small amplitude waves. equations fifth-order type where bottom intro...

A new way of deriving Bäcklund transformations for nonlinear partial differential evolution equations is presented and applied to the following equations: Korteweg–de Vries, Gardner, Burgers, generalized KdV and the fifth order equations of the KdV hierarchies. The presented method is based on the assumption of the existence of particular forms of the Bäcklund transformations. This assumption i...

in this paper, an application of homotopy perturbation method is appliedto nding the solutions of the seven-order sawada-kotera (ssk) and a lax'sseven-order kdv (lskdv) equations. then obtain the exact solitary-wave so-lutions and numerical solutions of the ssk and lskdv equations for the initialconditions. the numerical solutions are compared with the known analyticalsolutions. their rem...

We discuss the recent paper by Inan and Ugurlu [Inan I.E., Ugurlu Y., Exp-function method for the exact solutions of fifth order KdV equation and modified Burgers equation, Appl. Math. Comp. 217 (2010) 1294 – 1299]. We demonstrate that all exact solutions of fifth order KdV equation and modified Burgers equation by Inan and Ugurlu are trivial solutions that are reduced to constants. Moreover, w...

By means of the modified CK’s direct method, we give out the relationship between variable coefficients of the fifth-order KdV equation and the corresponding constant coefficient ones. At the same time, we have studied the generalized fifth-order KdV equation with constants coefficients using the Lie symmetry group methods. By applying the nonclassical symmetry method we found that the analyzed...

We study the problem of gravity surface waves for an ideal fluid model in (2+1)-dimensional case. apply a systematic procedure to derive Boussinesq equations given relation between orders four expansion parameters, amplitude parameter $\alpha$, long-wavelength $\beta$, transverse wavelength $\gamma$, and bottom variation $\delta$. derived only possible extensions Korteweg-de Vries equation, fif...