Exact solutions of (3+1)-dimensional nonlinear incompressible non-hydrostatic Boussinesq equations

The symmetries and the exact solutions of the （3＋l）-dimensional nonlinear incompressible non-hydrostatic Boussi- nesq （INHB） equations, which describe atmospheric gravity waves, are studied in this paper. The calculation on symmetry shows that the equations are invariant under the Galilean transformations, the scaling transformations, and the space-time translations. Three types of symmetry reduction equations and similar solutions for the （3＋ 1）-dimensional INHB equations are proposed. Traveling and non-traveling wave solutions of the INHB equations are demonstrated. The evolutions of the wind velocities in latitudinal, longitudinal, and vertical directions with space-time are demonstrated. The periodicity and the atmosphere viscosity are displayed in the （3＋1）-dimensional INHB system.

A more general form of lump solution,lumpoff,and instanton/rogue wave solutions of a reduced (3+1)-dimensional nonlinear evolution equation

In this manuscript,a reduced(3+1)-dimensional nonlinear evolution equation is studied.We first construct the bilinear formalism of the equation by using the binary Bell polynomials theory,then explore a lump solution to the special case for z=x.Furthermore,a more general form of lump solution of the equation is found which possesses seven arbitrary parameters and four constraint conditions.By cutting the lump by the induced soliton(s),lumpoff and instanton/rogue wave solutions are also constructed by the more general form of lump solution.

Numerical simulation of standing wave with 3D predictor-corrector finite difference method for potential flow equations

A three-dimensional （3D） predictor-corrector finite difference method for standing wave is developed. It is applied to solve the 3D nonlinear potential flow equa- tions with a free surface. The 3D irregular tank is mapped onto a fixed cubic tank through the proper coordinate transform schemes. The cubic tank is distributed by the staggered meshgrid, and the staggered meshgrid is used to denote the variables of the flow field. The predictor-corrector finite difference method is given to develop the difference equa- tions of the dynamic boundary equation and kinematic boundary equation. Experimental results show that, using the finite difference method of the predictor-corrector scheme, the numerical solutions agree well with the published results. The wave profiles of the standing wave with different amplitudes and wave lengths are studied. The numerical solutions are also analyzed and presented graphically.

Extended symmetry transformation of (3+1)-dimensional generalized nonlinear Schrdinger equation with variable coefficients

In this paper, the extended symmetry transformation of （3＋1）-dimensional （3D） generalized nonlinear Schrodinger （NLS） equations with variable coefficients is investigated by using the extended symmetry approach and symbolic computation. Then based on the extended symmetry, some 3D variable coefficient NLS equations are reduced to other variable coefficient NLS equations or the constant coefficient 3D NLS equation. By using these symmetry transformations, abundant exact solutions of some 3D NLS equations with distributed dispersion, nonlinearity, and gain or loss are obtained from the constant coefficient 3D NLS equation.

(3+1)维广义非线性发展方程的双线性Backlund变换与精确解

基于Hirota双线性方法和试探函数法,研究一个(3+1)维广义非线性发展方程的双线性Backlund变换和精确解问题。用Hirota双线性法,构造(3+1)维广义非线性发展方程的双线性形式和双线性Backlund变换。基于双线性形式和双线性Backlund变换,利用试探函数法与符号计算系统Mathematica,获得(3+1)维广义非线性发展方程的多种精确解,包括呼吸波解、复合型解、Lump周期解和孤子解,并分析解的相互作用情况。

A Generalized Hirota Ansatz to Obtain Soliton-Like Solutions for a (3+l)-Dimensional Nonlinear Evolution Equation

Instead of the usual Hirota ansatz,i.e.,the functions in bilinear equations being chosen as exponentialtypes,a generalized Hirota ansatz is proposed for a (3+1)-dimensional nonlinear evolution equation.Based on theresulting generalized Hirota ansatz,a family of new explicit solutions for the equation are derived.

Dynamics of solitons of the generalized(3+1)-dimensional nonlinear Schr(o|¨)dinger equation with distributed coefficients

We present three families of soliton solutions to the generalized （3＋l）-dimensional nonlinear Schrodinger equation with distributed coefficients. We investigate the dynamics of these solitons in nonlinear optics with some selected parameters. Different shapes of bright solitons, a train of bright solitons and dark solitons are observed. The obtained results may raise the possibilities of relevant experiments and potential applications.

Multiple exp-function method for soliton solutions of nonlinear evolution equations

We applied the multiple exp-function scheme to the（2＋1）-dimensional Sawada-Kotera（SK） equation and（3＋1）-dimensional nonlinear evolution equation and analytic particular solutions have been deduced. The analytic particular solutions contain one-soliton, two-soliton, and three-soliton type solutions. With the assistance of Maple, we demonstrated the efficiency and advantages of the procedure that generalizes Hirota＇s perturbation scheme. The obtained solutions can be used as a benchmark for numerical solutions and describe the physical phenomena behind the model.

Solving Cauchy Issues of Highly Nonlinear Elliptic Equations Using a Meshless Method

In this paper,we address 3D inverse Cauchy issues of highly nonlinear elliptic equations in large cuboids by utilizing the new 3D homogenization functions of different orders to adapt all the specified boundary data.We also add the average classification as an approximate solution to the nonlinear operator part,without requiring to cope with nonlinear equations to resolve the weighting coefficients because these constructions are owned many conditions about the true solution.The unknown boundary conditions and the result can be retrieved straightway by coping with a small-scale linear system when the outcome is described by a new 3D homogenization function,which is right to find the numerical solutions with the errors smaller than the level of noise being put on the over-specified Neumann conditions on the bottom of the cuboid.Besides,note that the new homogenization functions method(HFM)does not require dealing with the regularization and highly nonlinear equations.The robustness and accuracy of the HFM are verified by comparing the recovered results of several numerical experiments to the exact solutions in the entire region,even though a very large level of noise 50%is imposed on the over specified Neumann conditions.The numerical errors of our scheme are in the order of O(10^(−1))-O(10^(−4)).

A Simple Approach to Derive a Novel N-Soliton Solution for a (3+1)-Dimensional Nonlinear Evolution Equation

基于 Hirota 双线性的形式，没有采用标准不安技术的一条简单途径，为构造一个新奇 N-soliton 答案为被介绍一(3+1 ) 维的非线性的进化方程。而且，新奇 N-soliton 答案被显示在 Mathematica 的帮助下有反响的行为。

New lump solutions and several interaction solutions and their dynamics of a generalized(3+1)-dimensional nonlinear differential equation

In this paper,we mainly focus on proving the existence of lump solutions to a generalized(3+1)-dimensional nonlinear differential equation.Hirota’s bilinear method and a quadratic function method are employed to derive the lump solutions localized in the whole plane for a(3+1)-dimensional nonlinear differential equation.Three examples of such a nonlinear equation are presented to investigate the exact expressions of the lump solutions.Moreover,the 3d plots and corresponding density plots of the solutions are given to show the space structures of the lump waves.In addition,the breath-wave solutions and several interaction solutions of the(3+1)-dimensional nonlinear differential equation are obtained and their dynamics are analyzed.

Symmetry analysis and explicit solutions of the (3+1)-dimensional baroclinic potential vorticity equation

This paper investigates an important high-dimensional model in the atmospheric and oceanic dynamics-（3＋1）- dimensional nonlinear baroclinic potential vorticity equation by the classical Lie group method. Its symmetry algebra, symmetry group and group-invariant solutions are analysed. Otherwise, some exact explicit solutions are obtained from the corresponding （2＋1）-dimensional equation, the inviscid barotropic nondivergent vorticy equation. To show the properties and characters of these solutions, some plots as well as their possible physical meanings of the atmospheric circulation are given out.

Classification of All Single Traveling Wave Solutions to (3 + 1)-Dimensional Breaking Soliton Equation

In order to get the exact traveling wave solutions to nonlinear partial differential equation, the complete discrimination system for polynomial and direct integral method are applied to the considered equation. All single traveling wave solutions to the equation can be obtained. As an example, we give the solutions to (3 + 1)-dimensional breaking soliton equation.

Spatiotemporal Similaritons in (3+l)-Dimensional Inhomogeneous Nonlinear Medium with Cubic-Quintic Nonlinearity

我们获得准确空间与时间的 similaritons 到一(3+1 ) 维的不同类的非线性的 Schr ? dinger 方程，它与分布式的分散和获得在 cubic-quintic 非线性媒介描述光脉搏的繁殖。当某个相容性条件满足时，在椭圆形的方程的如此的自我类似的波浪和答案之间的一对一的通讯被发现。基于准确解决方案，我们在二种典型 soliton 控制系统讨论自我类似的 cnoidal 波浪和啁啾的 similaritons 的进化行为。而且，在啁啾的 similaritons 之间的比较和啁啾免费的 solitons 被给。

Propagations of Fresnel diffraction accelerating beam in Schrodinger equation with nonlocal nonlinearity

Accelerating beams have been the subject of extensive research in the last few decades because of their selfacceleration and diffraction-free propagation over several Rayleigh lengths.Here,we investigate the propagation dynamics of a Fresnel diffraction beam using the nonlocal nonlinear Schrodinger equation(NNLSE).When a nonlocal nonlinearity is introduced into the linear Schrodinger equation without invoking an external potential,the evolution behaviors of incident Fresnel diffraction beams are modulated regularly,and certain novel phenomena are observed.We show through numerical calculations,under varying degrees of nonlocality,that nonlocality significantly affects the evolution of Fresnel diffraction beams.Further,we briefly discuss the two-dimensional case as the equivalent of the product of two one-dimensional cases.At a critical point,the Airy-like intensity profile oscillates between the first and third quadrants,and the process repeats during propagation to yield an unusual oscillation.Our results are expected to contribute to the understanding of NNLSE and nonlinear optics.

一种3-PRS并联机器人位姿误差的数值计算方法

精度是衡量并联机器人工作质量优劣最主要的指标之一,常采用运动学推导和全微分的方法进行分析。文中针对公式复杂及全微分省略高次项带来精度下降等问题,用数值方法求解末端实际位姿来计算误差。在理想(不包含误差)的情况下通过逆解计算理论输入等参数;然后加上误差,用逆解求出的参数作为初值进行正解非线性方程组迭代求解,求得末端实际位姿,进而计算误差;最后用算例验证了方法的有效性及可行性。正解非线性方程组迭代求解直接采用高级语言的非线性方程组求解函数,文中采用的初值设置方法总能保证收敛到真实解,编程方便,计算精度高。

(3+1)维变系数Burgers方程的类孤子新解

提出函数变换与二阶常系数齐次线性常微分方程相结合的方法,借助符号计算系统Mathematica构造了(3+1)维变系数Burgers方程的类孤子新解,其由指数函数、三角函数和有理函数组成.

一个(3+1)维非线性演化方程的周期波解

基于一般的多维黎曼theta函数,直接推广双线性方法来构造(3+1)维非线性演化方程的黎曼theta函数周期波解.在多周期波解中,1-周期波的水平形态是一维的,2-周期波在独立的两个水平方向上有两个独立周期,因而它是1-周期波解的直接推广,并且其水平形态是二维的.在非线性方程双线性表示的基础上,运用双线性方法,构造出该(3+1)维非线性偏微分方程的1-孤子解和2-孤子解.这两种解之间的关系可以用极限的方法来描述,并相应地分析了多周期波解的渐近性态,得出在小振幅限制的极限情况下,周期波解将趋近于孤子解.

推广的Jacobi椭圆函数开法和(3+1)维Kadom tsev-Petviashvili方程的新解探索

文章将Jacobi椭圆函数展开法进行推广,在拟解中对参数j的取+值进行对称延拓。并以(3+1)维非线性Kadomtsev-Petviashvili方程为例,借助计算机代数系统Maple,求出新的周期解和孤波解。并通过图形分析法,给出了相应的讨论。

一类非线性(3+1)维波动方程的周期解

通过行波约化一类(3+1)维非线性波动方程和建立与立方非线性Klejn-Gordon方程间变换的联系,由此得到其孤立波解和周期解。