共查询到20条相似文献,搜索用时 0 毫秒
1.
An approximate homotopy symmetry method for nonlinear problems is proposed and applied to the sixth-order Boussinesq equation,which arises from fluid dynamics.We summarize the general formulas for similarity reduction solutions and similarity reduction equations of different orders,educing the related homotopy series solutions.Zero-order similarity reduction equations are equivalent to the Painlevé IV type equation or Weierstrass elliptic equation.Higher order similarity solutions can be obtained by solving... 相似文献
2.
以同伦近似对称法为理论依据研究了远场模型方程, 通过归纳各阶相似约化解和各阶相似约化方程的通式构造相应的同伦级数解. 各阶相似约化方程均为线性变系数常微分方程, 并且可以从零阶开始依次求解. 同伦模型中的辅助参数影响同伦级数解的收敛性.
关键词:
同伦近似对称法
远场模型方程
同伦级数解 相似文献
3.
YAO Ruo-Xia JIAO Xiao-Yu LOU Sen-Yue 《理论物理通讯》2009,51(5):785-788
Starting from Lie symmetry theory and combining with the approximate symmetry method, and using the package LieSYMGRP proposed by us, we restudy the perturbed Kuramoto-Sivashinsky (KS) equation. The approximate symmetry reduction and the infinite series symmetry reduction solutions of the perturbed KS equation are constructed. Specially, if selecting the tanh-type travelling wave solution as initial approximate, we not only obtain the general formula of the physical approximate similarity solutions, but also obtain several new explicit solutions of the given equation, which are first reported here. 相似文献
4.
Approximate direct reduction method: infinite series reductions to the perturbed mKdV equation 下载免费PDF全文
The approximate direct reduction method is applied to the perturbed mKdV
equation with weak fourth order dispersion and weak dissipation. The
similarity reduction solutions of different orders conform to formal
coherence, accounting for infinite series reduction solutions to the
original equation and general formulas of similarity reduction
equations. Painlevé II type equations, hyperbolic secant and
Jacobi elliptic function solutions are obtained for zero-order
similarity reduction equations. Higher order similarity reduction
equations are linear variable coefficient ordinary differential
equations. 相似文献
5.
6.
Approximate homotopy similarity reduction for the generalized Kawahara equation via Lie symmetry method and direct method 下载免费PDF全文
<正>This paper studies the generalized Kawahara equation in terms of the approximate homotopy symmetry method and the approximate homotopy direct method.Using both methods it obtains the similarity reduction solutions and similarity reduction equations of different orders,showing that the approximate homotopy direct method yields more general approximate similarity reductions than the approximate homotopy symmetry method.The homotopy series solutions to the generalized Kawahara equation are consequently derived. 相似文献
7.
We investigate the one-dimensional nonlinear SchrSdinger equation with a perturbation of polynomial type. The approximate symmetries and approximate symmetry reduction equations are obtained with the approximate symmetry perturbation theory. 相似文献
8.
Xi-zhong Liu 《中国物理 B》2022,31(5):50201-050201
A nonlocal Boussinesq equation is deduced from the local one by using consistent correlated bang method. To study various exact solutions of the nonlocal Boussinesq equation, it is converted into two local equations which contain the local Boussinesq equation. From the N-soliton solutions of the local Boussinesq equation, the N-soliton solutions of the nonlocal Boussinesq equation are obtained, among which the (N=2,3,4)-soliton solutions are analyzed with graphs. Some periodic and traveling solutions of the nonlocal Boussinesq equation are derived directly from the known solutions of the local Boussinesq equation. Symmetry reduction solutions of the nonlocal Boussinesq equation are also obtained by using the classical Lie symmetry method. 相似文献
9.
Junchao Chen 《Journal of Nonlinear Mathematical Physics》2014,21(3):454-472
In this paper, nonlocal symmetry of the (2+1) dimensional modified generalized long dispersive wave system and its applications are investigated. The nonlocal symmetry related to the eigenfunctions in Lax pairs is derived, and infinitely many nonlocal symmetries are obtained. By introducing three potentials, the prolongation is found to localize the given nonlocal symmetry. Various finite-and infinite-dimensional integrable models are constructed by using the nonlocal symmetry constraint method. Moreover, applying the general Lie symmetry approach to the enlarged system, the finite symmetry transformation and similarity reductions are computed to give novel exact interaction solutions. In particular, the explicit soliton-cnoidal wave solution is obtained for the modified generalized long dispersive wave system, and it can be reduced to the two-dark-soliton solution in one special case. 相似文献
10.
A new method to obtain approximate symmetry of nonlinear evolution equation from perturbations 下载免费PDF全文
A novel method for obtaining the approximate symmetry of a partial differential equation with a small parameter is introduced. By expanding the independent variable and the dependent variable in the small parameter series, we obtain more affluent approximate symmetries. The method is applied to two perturbed nonlinear partial differential equations and new approximate solutions are derived. 相似文献
11.
LIU Xi-Zhong 《理论物理通讯》2010,54(1):31-34
The Kawahara equation is studied through the approximate homotopy symmetry method. Under this method we get the similarity reduction solutions of the Kawahara equation, leading to the corresponding homotopy series solutions. Furthermore, the similarity solutions of the corresponding reduced linear ordinary differential equations are also considered. 相似文献
12.
Approximate any 1-state solutions of the Dirac equation for modified deformed Hylleraas potential by using the Nikiforov-Uvarov method 下载免费PDF全文
<正>We investigate the spin and pseudospin symmetries of the Dirac equation under modified deformed Hylleraas potential via a Pekeris approximation and the Nikiforov-Uvarov technique.A tensor interaction of Coulomb form is considered and its degeneracy-removing role is discussed in detail.The solutions are reported for an arbitrary quantum number in a compact form and useful numerical data are included. 相似文献
13.
New travelling wave solutions for combined KdV-mKdV equation and (2+1)-dimensional Broer- Kaup- Kupershmidt system 下载免费PDF全文
Some new exact solutions of an auxiliary ordinary differential
equation are obtained, which were neglected by Sirendaoreji {\it et
al in their auxiliary equation method. By using this method and
these new solutions the combined Korteweg--de Vries (KdV) and
modified KdV (mKdV) equation and (2+1)-dimensional
Broer--Kaup--Kupershmidt system are investigated and abundant exact
travelling wave solutions are obtained that include new solitary wave
solutions and triangular periodic wave solutions. 相似文献
14.
Residual symmetry reductions and interaction solutions of the (2+1)-dimensional Burgers equation 下载免费PDF全文
In nonlinear physics,it is very difficult to study interactions among different types of nonlinear waves.In this paper,the nonlocal symmetry related to the truncated Painleve′expansion of the(2+1)-dimensional Burgers equation is localized after introducing multiple new variables to extend the original equation into a new system.Then the corresponding group invariant solutions are found,from which interaction solutions among different types of nonlinear waves can be found.Furthermore,the Burgers equation is also studied by using the generalized tanh expansion method and a new Ba¨cklund transformation(BT)is obtained.From this BT,novel interactive solutions among different nonlinear excitations are found. 相似文献
15.
借助于符号计算软件Maple,通过一种构造非线性偏微分方程(组)更一般形式精确解的直接方法即改进的代数方法,求解(2+1) 维 Broer-Kau-Kupershmidt方程,得到该方程的一系列新的精确解,包括多项式解、指数解、有理解、三角函数解、双曲函数解、Jacobi 和 Weierstrass 椭圆函数双周期解.
关键词:
代数方法
(2+1) 维 Broer-Kau-Kupershmidt 方程
精确解
行波解 相似文献
16.
The extended symmetry approach is used to study the
general Korteweg-de Vries-type (KdV-type) equation. Several
variable-coefficient equations are obtained. The solutions of
these resulting equations can be constructed by the solutions of
original models if their solutions are well known, such as the
standard constant coefficient KdV equation and the standard compound
KdV--Burgers equation, and so on. Then any one of these
variable-coefficient equations can be considered as an original
model to obtain new variable-coefficient equations whose solutions
can also be known by means of transformation relations between
solutions of the resulting new variable-coefficient equations and the
original equation. 相似文献
17.
Maria V. Demina 《Physics letters. A》2010,374(39):4023-4029
Meromorphic traveling wave solutions of the Kawahara equation and the modified Kawahara equations are studied. An algorithm for constructing meromorphic solutions in explicit form is described. The classification problem for meromorphic solutions of autonomous nonlinear ordinary differential equations is discussed. 相似文献
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19.
Spin symmetry in the relativistic modified Rosen-Morse potential with the approximate centrifugal term 下载免费PDF全文
By applying a Pekeris-type approximation to the centrifugal term, we study the spin symmetry of a Dirac nucleon subjected to scalar and vector modified Rosen-Morse potentials. A complicated energy equation and associated two-component spinors with arbitrary spin-orbit coupling quantum number k are presented. The positive-energy bound states are checked numerically in the case of spin symmetry. The relativistic modified Rosen-Morse potential cannot trap a Dirac nucleon in the limiting case α→ 0. 相似文献