共查询到20条相似文献,搜索用时 0 毫秒
1.
GOU Ming QU Chang-Zheng 《理论物理通讯》2008,49(2):257-262
We study the functional separation of variables to the nonlinear heat equation: ut = (A(x)D(u)ux^n)x+ B(x)Q(u), Ax≠0. Such equation arises from non-Newtonian fluids. Its functional separation of variables is studied by using the group foliation method. A classification of the equation which admits the functional separable solutions is performed. As a consequence, some solutions to the resulting equations are obtained. 相似文献
2.
Extended Group Foliation Method and Functional Separation of Variables to Nonlinear Wave Equations 总被引:4,自引:0,他引:4
QU Chang-Zheng ZHANG Shun-Li 《理论物理通讯》2005,44(4):577-582
Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach. 相似文献
3.
Extended Group Foliation Method and Functional Separation of Variables to Nonlinear Wave Equations 总被引:1,自引:0,他引:1
QU Chang-Zheng ZHANG Shun-Li 《理论物理通讯》2005,44(10)
Generalized functional separation of variables to nonlinear evolution equations is studied in terms of the extended group foliation method, which is based on the Lie point symmetry method. The approach is applied to nonlinear wave equations with variable speed and external force. A complete classification for the wave equation which admits functional separable solutions is presented. Some known results can be recovered by this approach. 相似文献
4.
QU Chang-Zheng KANG Jing 《理论物理通讯》2008,49(1):9-16
In this paper, we study potential symmetries to certain systems of nonlinear diffusion equations. Thosesystems have physical applications in soil science, mathematical biology, and invariant curve flows in R^3. Lie point symmetries of the potential system, which cannot be projected to vector fields of the given dependent and independent variables, yield potential symmetries. The class of the system that admits potential symmetries is expanded. 相似文献
5.
Using the generalized conditional symmetry approach, we obtain a
number of new generalized
(1+1)-dimensional nonlinear wave
equations that admit derivative-dependent functional separable
solutions. 相似文献
6.
Using the generalized conditional symmetry approach, a complete list of canonicalforms for the Kortewegde-Vries type equations with which possessing derivative-dependent functional separable solutions (DDFSSs) is obtained.The exact DDFSSs of the resulting equations are explicitly exhibited. 相似文献
7.
Classification and Functional Separable Solutions to Extended Nonlinear Wave Equations 总被引:1,自引:0,他引:1
ZHANG Shun-Li LOU Sen-Yue QU Chang-Zheng YUE Rui-Hong 《理论物理通讯》2005,44(4):589-596
The generalized conditional symmetry approach is applied to study the variable separation of the extended wave equations. Complete classification of those equations admitting functional separable solutions is obtained and exact separable solutions to some of the resulting equations are constructed. 相似文献
8.
The generalized conditional symmetry approach is applied to study the variable separation of the extended wave equations. Complete classification of those equations admitting functional separable solutions is obtained and exact separable solutions to some of the resulting equations are constructed. 相似文献
9.
This paper is devoted to the study of functional variable separation for extended nonlinear elliptic equations.By applying the functional variable separation approach to extended nonlinear elliptic equations via the generalized conditional symmetry, we obtain complete classification of those equations which admit functional separable solutions (FSSs) and construct some exact FSSs to the resulting equations. 相似文献
10.
ZHANG Shun-Li LOU Sen-Yue 《理论物理通讯》2007,48(3):385-390
This paper is devoted to the study of functional variable separation for extended nonlinear elliptic equations. By applying the functional variable separation approach to extended nonlinear elliptic equations via the generalized conditional symmetry, we obtain complete classification of those equations which admit functional separable solutions (FSSs) and construct some exact FSSs to the resulting equations. 相似文献
11.
ZHANG Shun-Li ZHU Xiao-Ning WANG Yong-Mao LOU Sen-Yue 《理论物理通讯》2008,49(4):829-832
We give the generalized definitions of variable separable solutions to nonlinear evolution equations, and characterize the relation between the functional separable solution and the derivative-dependent functional separable solution. The new definitions can unify various kinds of variable separable solutions appearing in references. As application, we classify the generalized nonlinear diffusion equations that admit special functional separable solutions and obtain some exact solutions to the resulting equations. 相似文献
12.
Conditional Symmetry Groups of Nonlinear Diffusion Equations with x-Dependent Convection and Absorption 总被引:1,自引:0,他引:1
The generalized
conditional symmetry and sign-invariant approaches are developed
to study the nonlinear diffusion equations with x-dependent
convection and source terms. We obtain conditions under which the
equations admit the second-order generalized conditional
symmetries and the first-order sign-invariants on the solutions.
Several types of different generalized conditional symmetries and
first-order sign-invariants for the equations with diffusion of
power law are obtained. Exact
solutions to the resulting equations are constructed. 相似文献
13.
JIA Hua-Bing XU Wei 《理论物理通讯》2008,50(10):821-826
In this paper, we introduce a new invariant set Eo={u:ux=f'(x)F(u)+ε[g'(x)-f'(x)g(x)]F(u)×exp(-∫^u1/F(z)dz)}where f and g are some smooth functions of x, ε is a constant, and F is a smooth function to be determined. The invariant sets and exact sohltions to nonlinear diffusion equation ut = ( D(u)ux)x + Q(x, u)ux + P(x, u), are discussed. It is shown that there exist several classes of solutions to the equation that belong to the invariant set Eo. 相似文献
14.
In this paper, we introduce a new invariant set
˜E0={u:ux=fˊ(x)F(u)+ε [gˊ(x)
-fˊ(x)g(x)]F(u)exp(-∫u(1/F(z))dz), where f and g are some smooth functions of x, ε
is a constant, and F is a smooth function to be determined. The
invariant sets and exact solutions to nonlinear diffusion equation
ut=(D(u)ux)x+Q(x,u)ux+P(x,u), are discussed. It is shown
that there exist several classes of solutions to the equation that
belong to the invariant set
˜E0. 相似文献
15.
Conditional Symmetries and Solutions to a Class of Nonlinear Diffusion-Convection Equations 总被引:1,自引:0,他引:1
JI Li-Na QU Chang-Zheng 《理论物理通讯》2006,46(4):668-674
The present paper discusses a class of nonlinear diffusion-convection equations with source. The method that we use is the conditional symmetry method. It is shown that the equation admits certain conditional symmetries for coefficient functions of the equations. As a consequence, solutions to the resulting equations are obtained. 相似文献
16.
JI Li-Na QU Chang-Zheng 《理论物理通讯》2006,46(10)
The present paper discusses a class of nonlinear diffusion-convection equations with source. The method that we use is the conditional symmetry method. It is shown that the equation admits certain conditional symmetries for coefficient functions of the equations. As a consequence, solutions to the resulting equations are obtained. 相似文献
17.
为了描述对称空间中的无规运动,建立了群流形中的扩散方程,给出了紧致黎曼空间中扩散方程的一种具体形式,并进一步讨论了紧致黎曼空间中量子扩散运动. 相似文献
18.
QU ChangZheng 《理论物理通讯》1999,31(4):581-588
The generalized conditional symmetry method, which is a generalization of the conditional symmetry method, is used to study the nonlinear diffusion-convection-reaction equations. In particular, power law and exponential diffusivities are examined and we derive mathematical forms of the convection and reaction terms which permit a new type of generalized conditional symmetry. Some new exact solutions of the governing equations can be obtained by solving the systems of two or three ordinary differential equations which arise from the compatibility of the generalized conditional symmetries and the governing equations. 相似文献
19.
As an extension to the derivative-dependent functional variable separation approach, the approximate derivative-dependent functional variable separation approach is proposed, and it is applied to study the generalized diffusion equations with perturbation. Complete classification of these perturbed equations which admit approximate derivative-dependent functional separable solutions is obtained. As a result, the corresponding approximate derivative-dependent functional separable solutions to some resulting perturbed equations are derived by way of examples. 相似文献
20.
ZHANG Shun-Li 《理论物理通讯》2006,45(6):969-978
The generalized conditional symmetry is developed to study the variable
separation for equations of type uxt=A(u,ux)uxx+B(u,ux). Complete classification of those equations which admit derivative-dependent functional separable solutions is obtained and some of their
exact separable solutions are constructed. 相似文献