scholarly journals Perturbed Korteweg-de Vries equations symmetry analysis and conservation laws

2019 ◽  
Vol 23 (4) ◽  
pp. 2281-2289
Author(s):  
Yu-Shan Bai ◽  
Qi Zhang

Approximate symmetries for a coupled system of perturbed Korteweg-de Vries equations with small parameters are constructed by applying the method of approximate transformation groups. The optimal system of the presented approximate symmetries and a few approximate invariant solutions to the coupled system are obtained. Moreover, approximate conservation laws are constructed by using the partial Lagrangian method.

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Yu-Shan Bai ◽  
Qi Zhang

Approximate symmetries, which are admitted by the perturbed KdV equation, are obtained. The optimal system of one-dimensional subalgebra of symmetry algebra is obtained. The approximate invariants of the presented approximate symmetries and some new approximately invariant solutions to the equation are constructed. Moreover, the conservation laws have been constructed by using partial Lagrangian method.


2017 ◽  
Vol 72 (3) ◽  
pp. 269-279 ◽  
Author(s):  
Xiu-Bin Wang ◽  
Shou-Fu Tian ◽  
Chun-Yan Qin ◽  
Tian-Tian Zhang

AbstractIn this article, a generalised Whitham–Broer–Kaup–Like (WBKL) equations is investigated, which can describe the bidirectional propagation of long waves in shallow water. The equations can be reduced to the dispersive long wave equations, variant Boussinesq equations, Whitham–Broer–Kaup–Like equations, etc. The Lie symmetry analysis method is used to consider the vector fields and optimal system of the equations. The similarity reductions are given on the basic of the optimal system. Furthermore, the power series solutions are derived by using the power series theory. Finally, based on a new theorem of conservation laws, the conservation laws associated with symmetries of this equations are constructed with a detailed derivation.


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