ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)


Бифуркации в динамических системах различной природы

Bifurcations of one-parameter families of steady state regimes in model of a filtrational convection

Results of numerical investigation of bifurcations of one-parameter families of steady state regimes in a planar filtrational convection problem are presented. Galerkin’s method is applied for approximation of partial differential equations. As a result of the cosymmetry existence there are curves of equilibria with the hidden parameter. The algorithm of calculation of such curves is described. This algorithm can be applied to analyze systems with nonisolated sets of equilibria.

Complex dynamics in the system of two coupled discrete Rossler oscillators

We considered the discrete map with quasi-periodic dynamics in the wide band of the parameters and investigated the structure of the parameter plane of two coupled maps. We revealed the doublings of 3D-tori, the systems of 2D-tori and synchronization tongues and the resonance web. Also we revealed the attractors with complex structure and the largest Lyapunov exponent close to zero.

Bifurcations in van der pol oscillator with a hard excitation in a presence of parametrical noise: quasi-harmonic analyzes and the numerical simulations

In the work the behavior of a van der Pol oscillator with a hard excitation is considered near the excitation threshold under parametrical (multiplicative) Gaussian white noise disturbances, and in a case of the two noise sources presence: parametrical one and additive noise. The evolution of probability distribution is studied when a control parameter and a noise intensity are changed. A comparison of the theoretical results, obtained in the quasi-harmonic approach with the results  of numerical solutions of the oscillator stochastic equations is ful?lled.

«oscillator death» and quasiperiodic bifurcations in low- dimensional ensemble of van der pol oscillators

The dynamics of the four dissipatively coupled van der Pol oscillator is considered. Lyapunov chart is presented in the parameter plane and its arrangement is discusses. The e?ect of increase of the threshold for the «oscillator death» regime and the possibility of complete and partial broadband synchronization are revealed. We discuss the bifurcations of tori in the system at large frequency detuning of the oscillators, in particular, quasi-periodic saddle-node and Hopf bifurcations.

New type of bifurcations in the modified rayleigh–benard ? convection problem

The original Rayleigh–Benard convection is a standard example of the system where bifurcations occur with changing of a control parameter. In this paper we consider the modi?ed Rayleigh–Benard convection problem including radiative e?ects as well as gas sources on a surface. Such formulation leads to the identi?cation of new type of bifurcations in the problem besides the well-known Benard cells.

On scenarios of hyperbolic chaos destruction in model maps on torus with dissipative perturbation

In this paper we investigate modi?ed «Arnold cat» map with dissipative terms, in which a hyperbolic chaos exists for small perturbation magnitudes, and in a certain range a hyperbolic chaotic attractor with Cantor transversal structure takes place, collapsing with a further perturbation amplitude increase.

Attractor of smale–williams type in a ring system with periodic frequency modulation

A scheme of circular nonautonomous system is introduced, which is supposed to generate hyperbolic chaos. Its operation is based on doubling of phase on complete cycle of the signal transmission. This is a criterion for the Smale–Williams attractor to exist. The performance is realized due to smooth periodic variation of natural frequency in one of the two oscillatory subsystems, which compose the ring, from reference value to the doubled one.

Parametric generators with chaotic amplitude dynamics corresponding to attractors of smale–williams type

A new approach is considered to design of parametric generators of chaos with hyperbolic attractors on the basis of two alternately excited subsystems, each consisting of three oscillators, one of which plays the role of the pump source. In contrast to previously proposed schemes, the angular variable undergoing a multiple increase over each characteristic period is a quantity characterizing the amplitude ratio of two oscillators, rather then the phase of successive oscillation trains.

Optimum external impulse of low power for activation of one- dimensional dynamic system

In this paper we study the optimum form of external in?uence with low power necessary for activation of one-dimensional dynamical system. The Lagrange multipliers method is used. Optimum in?uence with low power and optimum law of change of a dynamical system state are determined analytically for linear dynamical system and numerically for nonlinear dynamical system. The opportunity of in?uence power reduction vs its duration is investigated.

Influence of fluctuations on evolution of three-dimensional torus in nonautonomous system

The transition to chaos through the destruction of three-dimensional torus is studied in a nonautonomous system with quasi-periodic impact as example. Analysis is carried out of the in?uence both of additive noise and frequency ?uctuations impact on the stability of three-dimensional torus. It is shown that under the in?uence of additive noise and frequency ?uctuations impact Lyapunov exponent remains negative. This allows to conclude that in this model three-dimensional torus is structurally stable in contrast to theautonomous system.

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