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41.
The paper presents and analyzes, from the point of view of smooth dynamic systems theory, a two-layer baroclinic model of
the troposphere in geostrophic approximation. The model describes airflow in β-channel within the tropospheric part of the
main Hadley circulation cell. It enables to obtain, after application of the Galerkin method, a fairly simple low-parametric
dynamic system describing the phenomena of non-linear interactions, bifurcations and blocking in the atmosphere. This enables
to take into consideration such basic factors influencing the atmospheric dynamics like the heat exchange within the surface,
orography, vertical variability of zonal wind and hydrostatic stability.
Impact of zonal thermal variability of the surface and vertical shear of zonal wind in the troposphere on the orographic bifurcation
was investigated and the oscillation character in the dynamic system after Hopf bifurcation of the second kind was analyzed.
Additionally, the model dynamics was investigated in conditions including momentum forcing in the upper and lower parts of
the troposphere and excluding orographic interaction, as well as in the conditions of thermal interaction between the troposphere
and the surface for the vertical shear of zonal wind in both tropospheric layers. Impact of the mean zonal wind in the troposphere
on the properties of model dynamics was assessed.
It was proved that zonally varied surface temperature and layered mean zonal wind in the atmosphere are the parameters that
have basic influence on the model dynamics. They cause numerous bifurcations and strongly influence the periods of oscillations
of the model variables. They are often Hopf bifurcations of the second kind during which tropospheric states fairly distant
from the ones before the bifurcations are generated. This significantly influences the model predictability. 相似文献
42.
43.
T. G. Vozmischeva 《Celestial Mechanics and Dynamical Astronomy》2000,77(1):37-48
The generalization of a test particle motion in a central field of two immovable point-like centers to the case of a constant
curvature space, on a three-dimensional sphere, is investigated in the paper. The bifurcation set in the plane of integrals
of motion is constructed and the classification of the domains of possible motion is carried out on a two-dimensional sphere.
The regularization of the Kepler’s problem on a two-dimensional sphere is carried out.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
44.
层状地基-非线性结构系统地震响应特性分析 总被引:1,自引:0,他引:1
根据从系统能量导出的地震动力方程,采用渐近解析法对层状地基 非线性结构系统的地震响应进行了分析,给出了共振区的振幅-频率以及相位-频率的解析公式,并对地基参数的不同取值,给出了一系列相应的计算结果。进而根据计算结果分析了地基参数对结构地震响应特性的影响,讨论了共振区畸变、振幅的分叉和突变现象以及“路径”效应等非线性动力特性。分析结果表明,同一类别地基的参数变化对结构的动力特性有显著的影响,按现行抗震设计方法对层状地基 非结构系统进行抗震分析时,可能产生较大的偏差,需考虑相互作用和非线性特性,以使设计参数更合理和优化。 相似文献
45.
顺层边坡岩体结构的模态幅值研究 总被引:4,自引:2,他引:2
针对顺层边坡岩体结构变形的特点,利用后屈曲能量准则建立了平衡稳定模态幅值方程,给出了平衡分叉点附近的邻域及边坡坡脚剪切滑动的判据。根据岩体边坡渐近性破坏的机理和流变变形的特征,分析了可能影响模态幅值的各种因素,给出了以坡长为控制变量的平衡稳定模态幅值的极值。 相似文献
46.
47.
Wave propagation and strain localization in a fully saturated softening porous medium under the non‐isothermal conditions
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The (THM) coupling effects on the dynamic wave propagation and strain localization in a fully saturated softening porous medium are analyzed. The characteristic polynomial corresponding to the governing equations of the THM system is derived, and the stability analysis is conducted to determine the necessary conditions for stability in both non‐isothermal and adiabatic cases. The result from the dispersion analysis based on the Abel–Ruffini theorem reveals that the roots of the characteristic polynomial for the THM problem cannot be expressed algebraically. Meanwhile, the dispersion analysis on the adiabatic case leads to a new analytical expression of the internal length scale. Our limit analysis on the phase velocity for the non‐isothermal case indicates that the internal length scale for the non‐isothermal THM system may vanish at the short wavelength limit. This result leads to the conclusion that the rate‐dependence introduced by multiphysical coupling may not regularize the THM governing equations when softening occurs. Numerical experiments are used to verify the results from the stability and dispersion analyses. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
48.
应用CUSP(尖角)突变模型研究了板内边界带地壳形变与强震的危险性判定及其预测的方法,并以鲜水河断裂带1973~1982年的动态大地测量和地震活动数据作了验证。结果表明:(1)强震前该断裂带地壳形变与蕴震系统经历了稳定平衡—不稳定平衡—稳定平衡—不稳定平衡—近于临界状态的过程。(2)系统的不稳定平衡状态在不同的观测点位具有同步性和持续性,且持续的时间与未来的地震强度有关。(3)预测未来事件发生的时间、震级、位移与实际发生的事件基本相符。 相似文献
49.
Mercè Ollé Joan R. Pacha Jordi Villanueva 《Celestial Mechanics and Dynamical Astronomy》2004,90(1-2):87-107
The paper deals with different kinds of invariant motions (periodic orbits, 2D and 3D invariant tori and invariant manifolds of periodic orbits) in order to analyze the Hamiltonian direct Hopf bifurcation that
takes place close to the Lyapunov vertical family of periodic orbits of the triangular equilibrium point L4 in the 3D restricted three-body problem (RTBP) for the mass parameter, μ greater than (and close to) μR (Routh’s mass parameter). Consequences of such bifurcation, concerning the confinement of the motion close to the hyperbolic
orbits and the 3D nearby tori are also described. 相似文献
50.
Abstract The onset of convection in a cylindrical fluid annulus is analyzed in the case when the cylindrical walls are rotating differentially, a temperature gradient in the radial direction is applied, and the centrifugal force dominates over gravity. The small gap approximation is used and no-slip conditions on the cylindrical walls are assumed. It is found that over a considerable range of the parameter space either convection rolls aligned with the axis of rotation or rolls in the perpendicular (azimuthal) direction are preferred. It is shown that by a suitable redefinition of parameters, results for finite amplitude Taylor vortices and for convection rolls in the presence of shear can be applied to the present problem. Weakly nonlinear results for transverse rolls in a Couette flow indicate the possibility of subcritical bifurcation for Prandtl numbers P less than 0.82. Heat and momentum transports are derived as functions of P and the problem of interaction between transverse and longitudinal rolls is considered. The relevance of the analysis for problems of convection in planetary and stellar atmospheres is briefly discussed. 相似文献