共查询到20条相似文献,搜索用时 125 毫秒
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一类大气尘埃等离子体扩散模型研究 总被引:4,自引:3,他引:1
研究了一类大气非线性尘埃等离子体扩散方程初值问题.首先在无扰动情形下,利用Fourier变换方法得到了尘埃等离子体扩散方程初值问题的精确解,接着引入一个同伦映射,并选取初始近似函数,再用同伦映射理论,依次求出了非线性尘埃等离子体扰动初值问题的各次近似解析解.并引用不动点理论,指出了近似解析解的有效性和各次近似解的近似度,通过举例, 用模拟曲线和表格作了近似对照.最后,简述了用同伦映射方法得到的近似解的物理意义.简叙了用上述方法得到的各次近似解具有便于求解、精度高等优点. 相似文献
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讨论了一阶迭代微分方程解析解的存在性,通过构造一个辅助方程的幂级数解给出该方程的解析解. 相似文献
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非饱和土壤水—维水平运动方程的拟解析解及其验证* 总被引:1,自引:0,他引:1
本文讨论了土壤水—维不饱和水平流方程的解析解问题.文中首先根据土壤水扩散率D与土壤含水量θ之间的经验关系.对原土壤水—维不饱和流方程作变量代换,将方程变为易于求解的形式,然后采用变量分离的方法并结合Boltzmann变换法进行求解.从而得出了解析表达式.同时这个解析解在土壤水—维水平不饱和流实验中得到了验证,从而证明了其解析表达式的正确性。 相似文献
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本文在解析框架下研究了两类Prandtl型方程的长时间适定性和爆破.对于经典Prandtl方程,本文证明了Paicu和Zhang (2011)得到的解的存在时间长度是最优的.对于从磁流体边界层模型导出的阻尼Prandtl方程,本文证明了小解析初值的整体适定性和对一类大解析初值的有限时间爆破. 相似文献
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研究了一类分数阶广义非线性扰动热波方程.首先在典型分数阶热波方程情形下得到解,接着用泛函分析映射方法,求出了分数阶广义非线性扰动热波方程初始边值问题的任意次近似解析解.最后简述了它的物理意义.求得的近似解析解,弥补了单纯用数值方法得到的模拟解的不足. 相似文献
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《Chaos, solitons, and fractals》2006,27(4):926-929
It is well known that there are envelope solitary waves in unmagnetized dusty plasmas which are described by a nonlinear Schrodinger equation (NLSE). A three dimension nonlinear Schrodinger equation for small but finite amplitude dust acoustic waves is first obtained for magnetized dusty plasma in this paper. It suggest that in magnetized dusty plasmas the envelope solitary waves exist. The modulational instability for three dimensional NLSE is studied as well. The regions of stability and instability are well determined in this paper. 相似文献
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Envelop solitons in dusty plasmas for warm dust 总被引:1,自引:0,他引:1
A nonlinear Schrödinger equation is obtained for the warm dusty plasmas. The modulational instability of envelop soliton is investigated in this paper. Both the temperature of the dust grains and the charge variations of dust grains affect the instability regions of the dusty plasmas. It also affect the amplitude and the width of the envelop soliton. 相似文献
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圆柱振荡绕流的三维不稳定性研究 总被引:4,自引:0,他引:4
通过数值求解三维不可压缩Navier-Stokes方程,研究了振荡圆柱绕流的旋涡不稳定性.研究表明,在一定的参数范围内,由于旋涡不稳定性,振荡流动由二维演化成三维流动,并沿圆柱轴向形成交错排列的三维涡结构.数值计算合理地预测了三维涡结构的空间失稳波长,并与实验测试值相符很好.文中还进一步研究了圆柱的受力特性,通过求解Morison方程,计算了圆柱的阻力和惯性力特性,其计算结果与已有的实验数据相吻合. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2007,12(5):636-642
The formally variable separation approach is used for handling the modified Zakharov–Kuznetsov equation in plasmas. New analytical solutions of nonlinear waves are formally derived for the governing equation of the system. The work introduces entirely new solutions and emphasizes the power of the newly developed method that can be used in problems with identical nonlinearities. 相似文献
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Jnanjyoti Sarma 《Chaos, solitons, and fractals》2009,39(1):277-281
An attempt has been made to obtain exact analytical traveling wave solution or simple wave solution of higher-order Korteweg–de Vries (KdV) equation by using tanh-method or hyperbolic method. The higher-order equation can be derived for magnetized plasmas by using the reductive perturbation technique. It is found that the exact solitary wave solution of higher-order KdV equation is obtained by tanh-method. Using this method, different kinds of nonlinear wave equations can be evaluated. The higher-order nonlinearity and higher-order dispersive effect can be observed from the solutions of the equations. The method is applicable for other nonlinear wave equations. 相似文献
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《Communications in Nonlinear Science & Numerical Simulation》2010,15(9):2245-2248
This paper talks about Langmuir waves in plasmas. The integration of the governing nonlinear Schrödinger’s equation with perturbation terms is carried out. Both Kerr law as well as the power law nonlinearity are considered. 相似文献
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Korteweg-de Vries (KdV)-type equations can describe some physical phenomena in fluids, nonlinear optics, quantum mechanics, plasmas, etc. In this paper, with the aid of symbolic computation, the integrable sixth-order KdV equation is investigated. Darboux transformation (DT) with an arbitrary parameter is presented. Explicit solutions are derived with the DT. Relevant properties are graphically illustrated, which might be helpful to understand some physical processes in fluids, plasmas, optics and quantum mechanics. 相似文献
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The multiple-scale perturbation analysis is used to study the perturbed nonlinear Schrödinger’s equation, that describes the Langmuir waves in plasmas. The perturbation terms include the non-local term due to nonlinear Landau damping. The WKB type ansatz is used to define the phase of the soliton that captures the corrections to the pulse where the standard soliton perturbation theory fails. 相似文献
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Chaudry Masood Khalique Abdullahi R. Adem 《Applied mathematics and computation》2010,216(10):2849-2496
In this paper, Lie group analysis is employed to derive some exact solutions of a generalized (3 + 1)-dimensional Kadomtsev-Petviashvili equation which describes the dynamics of solitons and nonlinear waves in plasmas and superfluids. 相似文献