Abstract
In this paper, we study a (3+1)-dimensional generalized shallow water wave equation with variable coefficients, which describes the flow below a pressure surface in a fluid. We give the Kadomtsev–Petviashvili hierarchy reduction and construct the multi-soliton solutions and semi-rational solutions in terms of the Gramian. For the multi-soliton solutions, we conclude that: (1) affects the directions for the two solitons to move; (2) there is the periodic interaction of the two solitons when
is a periodic function and (3) the magnitudes of the velocities for the two solitons increase as the amplitude of the periodic function
increases, where
represents the perturbed effect,
indicates the dispersion effect and t is an independent variable. For the first-order semi-rational solutions, we see that: (1) the fission with
and fusion with
appear; (2) there is the periodic interaction when
is a periodic function; (3) the magnitude of the velocity for the soliton increases as the amplitude of the periodic function
increases and (4) the lump becomes narrower as the amplitude of the periodic function
decreases, where
indicates the perturbed effect.
Acknowledgments
We express our sincere thanks to the Editors and Reviewers for their valuable comments.
Disclosure statement
No potential conflict of interest was reported by the author(s).
Notes
1 A polynomial is a tau function if and only if it satisfies
(for any ς,
), and the integration is taken along a small contour at
so that
, where
, ϖ is a positive integer,
's,
's and b are the independent variables,
,
and
are the vectors,
[Citation25].
2 (Bilinear) KP hierarchy is defined as a series of the bilinear forms satisfying (for any β), where h is a non-negative integer, κ is a positive integer,
's is the independent variable,
's is the coefficient polynomial,
is a vector,
,
's is the bilinear derivative operator [Citation25].