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对称性分析是自然科学研究中的重要方法之一. 利用对称性分析研究了一个描述两层流体体系的模型即耦合Burgers方程的对称性. 利用对称性给出了这个模型的四种对称性约化并给出了这些约化方程的一些特殊的严格解,如有理解、行波孤立子解和非行波孤立子解.
关键词:
对称性约化
耦合Burgers方程
孤立子 相似文献
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《Physics letters. A》2014,378(7-8):623-626
For the 2D and 3D Euler equations, their existing exact solutions are often in linear form with respect to variables x, y, z. In this paper, the Clarkson–Kruskal reduction method is applied to reduce the 2D incompressible Euler equations to a system of completely solvable ordinary equations, from which several novel nonlinear exact solutions with respect to the variables x and y are found. 相似文献
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Lie symmetry and conserved quantity of a system of first-order differential equations 总被引:5,自引:0,他引:5 下载免费PDF全文
This paper focuses on studying the Lie symmetry and a conserved quantity of
a system of first-order differential equations. The determining equations of
the Lie symmetry for a system of first-order differential equations, from
which a kind of conserved quantity is deduced, are presented. And their
general conclusion is applied to a Hamilton system, a Birkhoff system and a
generalized Hamilton system. Two examples are given to illustrate
the application of the results. 相似文献
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In this paper, Lie symmetry is investigated for a new integrable
coupled Korteweg--de Vries (KdV) equation system. Using some symmetry
subalgebra of the equation system, we obtain five types of the
significant similarity reductions. Abundant solutions of the coupled
KdV equation system, such as the solitary wave solution, exponential
solution, rational solution and polynomial solution, etc. are
obtained from the reduced equations. Especially, one type of
group-invariant solution of reduced equations can be acquired by
means of the Painlev\'e I transcendent function. 相似文献
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In this paper, the symmetry method has been carried over to the generalized variable coefficients Zakharov- Kuznetsov equation. The infinitesimal symmetries and the optimal system are deduced and from this optimal system seven basic fields are determined, and for every vector field in the optimal system the admissible forms of the coefficients are found and this also leads us to transform the given equation into partial differential equations in two variables. After using some referenced transformations the mentioned partial differential equations eventually reduce to ordinary differential equations. The search for solutions to those equations has yielded many exact solutions in most cases. 相似文献
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We demonstrate the approximate nature of the Onsager-Casimir relations for the example of the linearized Burnett equations for a dilute gas. For any discussion of Onsager relations the choice of a correct set of thermodynamic forces and fluxes is of course crucial. By retracing the Chapman-Enskog procedure, we show that the usual expressions for the thermodynamic forces require modifications at the Burnett level. However, inclusion of these terms does not remedy the violation of Onsager symmetry first noticed by McLennan. A modified version of the Onsager symmetry that involves thermodynamic forces derived from an entropy Lagrangian rather than from the entropy itself does remain valid on the Burnett level. Throughout, we allow for the presence of an external potential; the Burnett equations including potential terms are derived in an appendix for a set of variables particularly suited for our discussion. We stress that in discussing Onsager relations one should use the full thermodynamic fluxes rather than their dissipative parts only, in spite of the fact that only the latter contribute to the entropy production. 相似文献
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In this paper, the symmetry method has been carried over to the generalizedvariable coefficients Zakharov-Kuznetsov equation. The infinitesimalsymmetries and the optimal system are deduced and from this optimal systemseven basic fields are determined, and for every vector field in the optimalsystem the admissible forms of the coefficients are found and this also leadsus to transform the given equation into partial differential equations intwo variables. After using some referenced transformations the mentionedpartial differential equations eventually reduce to ordinary differentialequations. The search for solutions to those equations has yielded manyexact solutions in most cases. 相似文献
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According to the conjecture based on some known facts of integrable
models, a new (2+1)-dimensional supersymmetric integrable bilinear
system is proposed. The model is not only the extension of the known
(2+1)-dimensional negative Kadomtsev--Petviashvili equation but also
the extension of the known (1+1)-dimensional supersymmetric
Boussinesq equation. The infinite dimensional Kac--Moody--Virasoro
symmetries and the related symmetry reductions of the model are
obtained. Furthermore, the traveling wave solutions including
soliton solutions are explicitly presented. 相似文献
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研究奇异系统Hamilton正则方程的形式不变性即Mei对称性,给出其定义、确定方程、限制方程和附加限制方程.研究奇异系统Hamilton正则方程的Mei对称性与Noether对称性、Lie对称性之间的关系,寻求系统的守恒量.给出一个例子说明结果的应用.
关键词:
奇异系统
Hamilton正则方程
约束
对称性
守恒量 相似文献
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Bosonization approach is applied in solving the most general N=1 supersymmetric Korteweg de-Vries equation with an arbitrary parameter a (sKdV-a) equation. By introducing some fermionic parameters in the expansion of the superfield, the sKdV-a equation is transformed to a new coupled bosonic system. The Lie point symmetries of this model are considered and similarity reductions of it are conducted. Several types of similarity reduction solutions of the coupled bosonic equations are simply obtained for all values of a. Some kinds of exact solutions of the sKdV-a equation are discussed which was not considered integrable previously. 相似文献
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In this paper, we use our method to solve the extended Lotka--Volterra equation and
discrete KdV equation. With the help of Maple, we obtain a number of exact solutions
to the two equations including soliton solutions presented by hyperbolic functions
of \sinh and \cosh, periodic solutions presented by trigonometric functions of
\sin and \cos, and rational solutions. This method can be used to solve some
other nonlinear difference--differential equations. 相似文献
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In this article, Quispel, Roberts and Thompson type of nonlinear partial difference equation with two independent variables is considered and identified five distinct nonlinear partial difference equations admitting continuous point symmetries quadratic in the dependent variable. Using the degree growth of iterates the integrability nature of the obtained nonlinear partial difference equations is discussed. It is also shown how to derive higher order ordinary difference equations from the periodic reduction of the identified nonlinear partial difference equations. The integrability nature of the obtained ordinary difference equations is investigated wherever possible. 相似文献
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A new variable coefficient algebraic method and non-travelling wave solutions of nonlinear equations 下载免费PDF全文
In this paper, a new auxiliary equation method is presented of constructing more new non-travelling wave solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than projective Riccati equation method. In order to illustrate the validity and the advantages of the method, (2+1)-dimensional asymmetric Nizhnik-Novikov-Vesselov equation is employed and many new double periodic non-travelling wave solutions are obtained. This algorithm can also be applied to other nonlinear differential equations. 相似文献