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1.
基于一般的浅水波方程, 根据大尺度正压大气的特点, 得到无量纲的控制大尺度大气的动力学非线性方程组. 利用多尺度法, 由无量纲的动力学方程组导出了扰动位势的非线性控制方程. 采用椭圆方程构造该扰动位势控制方程的解, 获得了扰动位势和速度的多周期波与冲击波(爆炸波) 并存的解析解. 扰动位势的解表明经向和纬向具有不同周期和波长的周期波, 且都受纬向孤波的调制; 速度的解表明大尺度大气流动存在气旋和反气旋周期性分布的现象.
关键词:
浅水波方程
大尺度正压大气
解析解
非线性波 相似文献
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考虑了一种无反馈的作用机理,通过分析定常强迫作用下R?ssler系统的分岔图和Lyapunov指数谱,发现定常强迫能够导致混沌系统产生振幅死亡.这种现象的产生类似于耦合的极限环系统和耦合的R?ssler系统,弱定常强迫作用下的R?ssler系统经由一个周期运动被驱动到系统自身的一个平衡点上.进一步对受迫系统时间序列的研究表明,当定常强迫强度超过一个临界值时,系统的状态不断在小振幅周期运动与静止之间交替出现.
关键词:
振幅死亡
定常强迫
R?ssler系统 相似文献
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利用扰动法,由包括耗散和地形的准地转位涡度方程导出了强迫mKdV-Burgers方程,求得了小耗散情形下mKdV-Burgers方程的近似分析解,分析了mKdV孤波质量和能量的时间演变特性。对给定的局地地形,利用拟谱法对强迫mKdV-Burgers方程进行了数值求解。结果显示,小耗散的存在使弧波的振幅和移速随时间缓慢地减小,孤波宽度则随时间缓慢增大;在耗散和地形强迫的非线性系统中,在孤波与地形的相互作用中,耗散的存在使孤波在强迫区附近振荡传播,这有利于大振幅扰动的形成。 相似文献
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运用重合度理论探讨了一类非线性问题的周期解.然后将其应用于一个厄尔尼诺大气物理机理振荡,简捷地得到了该模型的周期解.
关键词:
非线性
厄尔尼诺现象
周期解 相似文献
9.
利用包括地形外源和湍流耗散的准地转涡度方程导出了包含强迫项和湍流耗散项的非齐次强迫BDO-Burgers方程,求出了小耗散存在情况下BDO-Burgers方程的近似解析解,讨论了代数孤立波的质量和能量的守恒关系,最后,对给定的弱切变基本气流和避地地形强迫,数据积分强迫BDO-Burgers方程,求得了不同参数下的数值解。 相似文献
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封闭圆内开缝圆自然对流的非线性特性研究 总被引:2,自引:0,他引:2
本文通过数值计算对封闭圆内开缝圆自然对流的非线性特性进行了研究。数值计算以整个流场为计算区域,采用非稳态数学模型和具有QUICK差分格式的SIMPLE算法。计算结果表明,在不同参数下流动和换热存在稳态定常解、周期性振荡解、拟周期性振荡解和非周期性振荡解。稳态定常解的相图是一个点;周期性振荡解的相图是一个极限环,对应功率谱含一个基频及其谐波;拟周期性振荡解的相图为环面,对应功率谱含两个不相关的频率及它们的线性组合频率;非周期性振荡解的功率谱为无规则的宽带连续谱。 相似文献
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TANG Xiao-Yan Padma Kant Shukla 《理论物理通讯》2008,49(1):229-230
Applying the classical Lie symmetry approach to the barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a β-plane channel, we find a new symmetry, which is not presented in a previous work [F. Huang, Commun. Theor. Phys. (Beijing, China) 42 (2004) 903]. A general finite transformation group is obtained based on the full Lie point symmetry, Furthermore, two new types of similarity reduction solutions are obtained. 相似文献
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正压流体中,从有外源的准地转位涡方程出发采用摄动方法和时空伸长变换推导了具有β效应、地形效应和外源的强迫Rossby孤立波方程,得到孤立Rossby波振幅的演变满足带有地形与外源强迫的非齐次 Boussinesq方程的结论. 通过分析孤立Rossby波振幅的演变,指出β效应、地形效应以及外源都是诱导Rossby孤立波产生的重要因素,说明在地形强迫效应和非线性作用相平衡的假定下,Rossby孤立波振幅的演变满足非齐次Boussinesq方程,给出在切变基本气流下地形和正压流体中R 相似文献
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在层结流体中, 从带有地形、热外源耗散的下边界条件以及带有热外源的准地转位涡方程开始, 使用小参数展开方法和多尺度时空伸长变换推导出了具有热外源、β效应和地形效应的强迫Rossby孤立波方程, 得到孤立Rossby振幅满足的带有地形与热外源的非齐次非线性的Schrödinger方程. 通过分析Rossby孤立波振幅的变化, 指出了热外源、β效应和地形效应都是诱导Rossby孤立波产生的重要因素, 给出了切变基本流下地形、热外源和层结流体中Rossby的相互作用. 相似文献
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正压流体中,从有外源的准地转位涡方程出发采用摄动方法和时空伸长变换推导了具有β效应、地形效应和外源的强迫Rossby孤立波包方程,得到孤立Rossby波振幅的演变满足带有地形与外源强迫的非齐次非线性Schrödinger方程的结论. 通过分析孤立Rossby波包振幅的演变,指出了β效应、地形效应以及外源都是诱导Rossby孤立波产生的重要因素,说明了在地形强迫效应和非线性作用相平衡的假定下,Rossby孤立波包振幅的演变满足非齐次非线性Schrödinger
关键词:
Rossby波包
β效应')" href="#">β效应
地形
Schrödinger方程 相似文献
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A simple shallow-water model with influence of external forcing on
a β-plane is applied to investigate the nonlinear equatorial
Rossby waves in a shear flow. By the perturbation method, the
extended variable-coefficient KdV equation under an external
forcing is derived for large amplitude equatorial Rossby wave in a
shear flow. And then various periodic-like structures for these
equatorial Rossby waves are obtained with the help of Jacobi
elliptic functions. It is shown that the external forcing plays an
important role in various periodic-like structures. 相似文献
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The (2 1)-dimensional nonlinear barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a beta-plane channel is investigated by using the classical Lie symmetry approach. Some types of group-invariant wave solutions are expressed by means of the lower-dimensional similarity reduction equations. In addition to the known periodic Rossby wave solutions, some new types of exact solutions such as the ring solitary waves and the breaking soliton type of vorticity solutions with nonlinear and nonconstant shears are also obtained. 相似文献
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The (2 1)-dimensional nonlinear barotropic and quasi-geostrophic potential vorticity equation without forcing and dissipation on a beta-plane channel is investigated by using the classical Lie symmetry approach. Some types of group-invariant wave solutions are expressed by means of the lower-dimensional similarity reduction equations. In addition to the known periodic Rossby wave solutions, some new types of exact solutions such as the ring solitary waves and the breaking soliton type of vorticity solutions with nonlinear and nonconstant shears are also obtained. 相似文献
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Summary The essential features of the steady circulation of the western Mediterranean are reproduced by means of a vertically integrated
model. In the framework of barotropic theory, it is shown how the effects of the geometry of the basin, including the islands,
of the variable bottom topography and of the forcing of the flow at the Gibraltar Strait concur in determining the circulation
pattern. Some observed features in particular regions, such as the Ligurian Sea, which are not reproduced by the model, indicate
where baroclinic and/or wind-driven dynamics are likely to dominate.
Paper presented at the 1o Congresso del Gruppo Nazionale per la Fisica dell'Atmosfera e dell'Oceano, June 19–22, 1984, Rome. 相似文献
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Periodic Structure of Equatorial Envelope Rossby Wave Under
Influence of Diabatic Heating 总被引:1,自引:0,他引:1
FUZun-Tao CHENZhe LIUShi-Da LIUShi-Kuo 《理论物理通讯》2004,42(1):43-48
A simple shallow-water model with influence of diabatic heating on a β-plane is applied to investigate the nonlinear equatorial Rossby waves in a shear flow. By the asymptotic method of multiple scales, the cubic nonlinear Schro^edinger (NLS for short) equation with an external heating source is derived for large amplitude equatorial envelope Rossby wave in a shear flow. And then various periodic structures for these equatorial envelope Rossby waves are obtained with the help of Jacob/elliptic functions and elliptic equation. It is shown that phase-locked diabatic heating plays an important role in periodic structures of rational form. 相似文献
20.
Recently F. Huang [Commun. Theor. Phys. 42 (2004) 903] and X. Tang and P.K. Shukla [Commun. Theor. Phys. 49 (2008) 229] investigated symmetry properties of the barotropic potential vorticity equation without forcing anddissipation on the beta-plane. This equation is governed by two dimensionless parameters, F and β, representing the ratio of the characteristic length scale to the Rossby radius of deformation and the variation of earth' angular rotation, respectively. In the present paper it is shown that in the case F≠ 0 there exists a well-defined point transformation to set β= 0. Theclassification of one- and two-dimensional Lie subalgebras of the Lie symmetry algebra of the potential vorticity equation is given for the parameter combination F≠0 and β = 0. Based upon this classification, distinct classes of group-invariant solutions are obtained and extended to the case β≠ 0. 相似文献