scholarly journals Scaling Symmetries and Conservation Laws for Variable-coefficients Nonlinear Dispersive Equations

2019 ◽  
Vol 20 (3) ◽  
pp. 429
Author(s):  
Érica M. Silva ◽  
Wescley L. Souza

Scaling symmetries arise in different branches of physics, and symmetry-based approaches are powerful tools for studying scaling-invariant models since they can provide conservation laws that are not obvious by inspection. In this framework, the class of variable-coefficients nonlinear dispersive equations vc$K(m,n)$, which contains several important evolution equations modeling nonlinear phenomena, is considered. For some of its scaling-invariant subclasses, we study its nonlinear self-adjointness and construct eight new local conservation laws associated with scaling symmetries by using a general theorem on conservation laws and the multipliers method. The property of scale invariance of those equations led to five conservation laws with a direct physical interpretation: energy, center of mass, and mass are the conserved quantities obtained in some cases. 

2013 ◽  
Vol 14 (1) ◽  
pp. 109-118 ◽  
Author(s):  
I. L. Freire ◽  
J. C. S. Sampaio

In this work we revisit some recent results on conservation laws for a class of fifth-order evolution equations up to fifth-order.


2014 ◽  
Vol 760 ◽  
pp. 368-386 ◽  
Author(s):  
Alexei F. Cheviakov ◽  
Martin Oberlack

AbstractLocal conservation laws are systematically constructed for three-dimensional time-dependent viscous and inviscid incompressible fluid flows, in primitive variables and vorticity formulation, using the direct construction method. Complete sets of local conservation laws in primitive variables are derived for the case of conservation law multipliers depending on derivatives up to the second order. In the vorticity formulation, there exists an infinite family of vorticity-dependent conservation laws involving an arbitrary differentiable function of space and time, holding for both viscous and inviscid cases. The infinite conservation law family is used to generate further independent hierarchies of conservation laws that essentially involve vorticity and arbitrary flow parameters, which are determined by known evolution equations such as those for momentum, energy or helicity, though not necessarily in the form of a conservation law. The new conservation laws are not restricted to any reduced flow geometry such as planar or axisymmetric limits. Examples are considered.


2016 ◽  
Vol 71 (5) ◽  
pp. 475-480 ◽  
Author(s):  
Emrullah Yaşar ◽  
Sait San

AbstractIn this article, we established abundant local conservation laws to some nonlinear evolution equations by a new combined approach, which is a union of multiplier and Ibragimov’s new conservation theorem method. One can conclude that the solutions of the adjoint equations corresponding to the new conservation theorem can be obtained via multiplier functions. Many new families of conservation laws of the Pochammer–Chree (PC) equation and the Kaup–Boussinesq type of coupled KdV system are successfully obtained. The combined method presents a wider applicability for handling the conservation laws of nonlinear wave equations. The conserved vectors obtained here can be important for the explanation of some practical physical problems, reductions, and solutions of the underlying equations.


2021 ◽  
Vol 403 ◽  
pp. 126203
Author(s):  
Gianluca Frasca-Caccia ◽  
Peter E. Hydon

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