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V. V. Yanovsky

Publications and source records attributed to V. V. Yanovsky.

36 records · Page 2Linked to original sources
arXiv2018

Chaotic magnetoconvection in a non-uniformly rotating electroconductive fluids

We study a new type of magnetoconvection in a nonuniform rotating plasma layer under a constant vertical magnetic field. To describe the weakly nonlinear stage of convection we apply Galerkin-truncated approximation and we obtain the system of equations of Lorentz type. A numerical analysis of these equations shows the presence of chaotic behavior of convective flows. Criteria for the appearance of chaotic motions are found depending on the convection parameters (Rayleigh number $\textrm{Ra}$), magnetic field (Chandrasekhar number $\textrm{Q}$), rotation (Taylor number $\textrm{Ta}$) for the Keplerian angular velocity profile $(\textrm{Ro}=-3/4)$ of the medium.

astro-ph.EP↗
arXiv2017

Nonlinear dynamo in obliquely rotating electroconductive fluids

In the present paper, we study a new type of large-scale instability, which arises in obliquely rotating electroconductive fluids with a small-scale external force of zero helicity. This force excites small-scale velocity oscillations with a small Reynolds number. We used the method of multiscale asymptotic expansions. The nonlinear equations for vortex and magnetic perturbations motions are obtained up to third order in Reynolds number. The linear stage of the magneto-vortex dynamo, arising as a result of instabilities of the type of hydrodynamic and magnetohydrodynamic $α$ - effects, is investigated. Stationary solutions of nonlinear equations of magneto-vortex dynamo in the form of localized chaotic structures are found numerically.

physics.plasm-ph↗
arXiv2017

Nonlinear vortex structures in obliquely rotating stratified fluids driven by small scale non helical forces

In this paper, we study a new type of large-scale instability in obliquely rotating stratified fluids with small scale non-helical turbulence. The small-scale turbulence is generated by the external force with zero helicity and low Reynolds number. The theory uses the method of multiscale asymptotic developments. The nonlinear equations for large scale motions are obtained in the third order of the perturbation theory. In this paper, we consider the linear instability and the stationary nonlinear modes. We obtain solutions in the form of nonlinear Beltrami waves and localized vortex structures as kinks of new type.

physics.flu-dyn↗
arXiv2016

Nonlinear Dynamo

In this manuscript using the asymptotic method of multiscale nonlinear theory we construct a nonlinear theory of the appearance of large-scale structures in the stratified conductive medium with the presence of small-scale oscillations of the velocity field and magnetic fields. These small-scale stationary oscillations are maintained by small external sources at low Reynolds numbers. We obtain a nonlinear system of equations describing the evolution of large-scale structures of the velocity field and magnetic fields. The linear stage of evolution leads to the known instability. In this article we consider the stationary large-scale structures of a magnetic field arising at stabilization of linear instability.

astro-ph.EP↗
arXiv2016

Modified Planck units

Planck units are natural physical scales of mass, length and time, built with the help of the fundamental constants $\hbar, c, G$. The functional role of the constants used for the construction of Planck units is different. If the first two of them represent the limits of the action and the speed of light and underlie quantum mechanics and special relativity, the Newton's constant $G$ "only" fixes the absolute value of the gravitational forces. It seems natural to make a set of fundamental constants more consistent and more effective if used to build Planck units only limit values. To this end, in addition to the limit values $\hbar $ and $c$ we introduce an additional limit value - a maximum power in nature. On the basis of these values, a modification of the Planck unit system is proposed. The proposed modification leaves unchanged the numerical values of Planck units, however, opens up exciting new possibilities for interpreting the known results and for obtaining new ones.

physics.gen-ph↗
arXiv2015

The Large scale instability in rotating fluid with small scale force

In this paper, we find a new large scale instability displayed by a rotating flow in forced turbulence. The turbulence is generated by a small scale external force at low Reynolds number. The theory is built on the rigorous asymptotic method of multi-scale development. The nonlinear equations for the instability are obtained at the third order of the perturbation theory. In this article, we explain a detailed study of the nonlinear stage of the instability and generation vortex kinks.

physics.flu-dyn↗
arXiv2013

Reflection of nanoparticles

This work is devoted to molecular dynamics modeling of collision of nanoparticle having a small number of degrees of freedom with a structureless plain. The new regularities are established that determine properties of such particles. Generalized collision law is obtained where particle properties are determined by two coefficient, on of which corresponds to restitution coefficient. The discovered regularity predicts the existence of anomalous mode of particle reflection from a massive plain. In this mode, velocity of nanoparticle after reflection from a plain can exceed the initial one. The criterion of realization of such mode is obtained. Anomalous collision mode was observed during numerical modeling. Physical mechanism are discussed of phenomena that are observed during numerical experiments.

cond-mat.mes-hall↗
arXiv2012

Interaction of a dipole point vortex with flat boundary

In this work we have found an exact solution for the problem of the movement of a dipole type point vortex in an area of fluid limited by a flat boundary. We also present a solution to the problem of dipole point vortex motion in a right angle. It is shown that unlike a usual point vortex, the dipole vortex always comes away from the boundary asymptotically. This important feature of the dipole vortex allows it to be considered to be one of the efficient mechanisms of vorticity transfer from boundary to media.

physics.flu-dyn↗
arXiv2012

Vortex structures with complex points singularities in the two-dimensional Euler equation. New exact solutions

In this work we found the new class of exact stationary solutions for 2D-Euler equations. Unlike of already known solutions, the new one contain complex singularities. We consider as complex, point singularities which have the vector field index greater than one. For example, the dipole singularity is complex because its index is equal to two. We present in explicit form a large class of exact localized stationary solutions for 2D-Euler equations with the singularity which index is equal to three. The obtained solutions are expressed in terms of elementary functions. These solutions represent complex singularity point surrounded by vortex satellites structure. We discuss also motion equation of singularities and conditions for singularity point stationarity which provides the stationarity of complex vortex configuration.

physics.flu-dyn↗
arXiv2011

Singularities Motion Equations in 2-Dimensional Ideal Hydrodynamics of Incompressible Fluid

In this paper, we have obtained motion equations for a wide class of one-dimensional singularities in 2-D ideal hydrodynamics. The simplest of them, are well known as point vortices. More complicated singularities correspond to vorticity point dipoles. It has been proved that point multipoles of a higher order (quadrupoles and more) are not the exact solutions of two-dimensional ideal hydrodynamics. The motion equations for a system of interacting point vortices and point dipoles have been obtained. It is shown that these equations are Hamiltonian ones and have three motion integrals in involution. It means the complete integrability of two-particle system, which has a point vortex and a point dipole.

nlin.SI↗
arXiv2004

Fractional Fokker--Planck Equation for Nonlinear Stochastic Differential Equations Driven by Non-Gaussian Levy Stable Noises

The Fokker-Planck equation has been very useful for studying dynamic behavior of stochastic differential equations driven by Gaussian noises. In this paper, we derive a Fractional Fokker--Planck equation for the probability distribution of particles whose motion is governed by a {\em nonlinear} Langevin-type equation, which is driven by a non-Gaussian Levy-stable noise. We obtain in fact a more general result for Markovian processes generated by stochastic differential equations.}

math.AP↗
arXiv2002

New Scenario to Chaos Transition in the Mappings with Discontinuities

We consider a many-parametric piecewise mapping with discontinuity. That is a one dimensional model of singular dynamic system. The stability boundary are calculated analytically and numerically. New typical features of stable cycle structures and scenario to chaos transition provoked by discontinuity are found.

nlin.CD↗
arXiv2001

Stochastic Resonance in a Periodically Modulated Dissipative Nuclear Dynamics

A fission decay of highly excited periodically driven compound nuclei is considered in the framework of Langevin approach. We have used residual-time distribution (RTD) as the tool for studying of dynamic features in a presence of periodic perturbation. The structure of RTD essentially depends on the relation between Kramers decay rate and the frequency of the periodic perturbation. In particular, intensity of the first peak in RTD has a sharp maximum at certain nuclear temperature depending on the frequency of the periodic perturbation. This maximum should be considered as first-hand manifestation of stochastic resonance in nuclear dynamics.

nlin.CD↗
arXiv2000

Fractional Fokker-Planck Equation for Nonlinear Stochastic Differential Equations Driven by Non-Gaussian Levy Stable Noises

The Fokker-Planck equation has been very useful for studying dynamic behavior of stochastic differential equations driven by Gaussian noises. However, there are both theoretical and empirical reasons to consider similar equations driven by strongly non-Gaussian noises. In particular, they yield strongly non-Gaussian anomalous diffusion which seems to be relevant in different domains of Physics. We therefore derive in this paper a Fractional Fokker-Planck equation for the probability distribution of particles whose motion is governed by a nonlinear Langevin-type equation, which is driven by a Levy-stable noise rather than a Gaussian. We obtain in fact a general result for a Markovian forcing. We also discuss the existence and uniqueness of the solution of the Fractional Fokker-Planck equation

chao-dyn↗
arXiv2000

Levy Anomalous Diffusion and Fractional Fokker--Planck Equation

We demonstrate that the Fokker-Planck equation can be generalized into a 'Fractional Fokker-Planck' equation, i.e. an equation which includes fractional space differentiations, in order to encompass the wide class of anomalous diffusions due to a Levy stable stochastic forcing. A precise determination of this equation is obtained by substituting a Levy stable source to the classical gaussian one in the Langevin equation. This yields not only the anomalous diffusion coefficient, but a non trivial fractional operator which corresponds to the possible asymmetry of the Levy stable source. Both of them cannot be obtained by scaling arguments. The (mono-) scaling behaviors of the Fractional Fokker-Planck equation and of its solutions are analysed and a generalization of the Einstein relation for the anomalous diffusion coefficient is obtained. This generalization yields a straightforward physical interpretation of the parameters of Levy stable distributions. Furthermore, with the help of important examples, we show the applicability of the Fractional Fokker-Planck equation in physics.

nlin.CD↗
arXiv1997

Multifractal Interpolation of Universal Multifractals

Basing on invariant properties of universal multifractals we propose a simple algorithm for interpolation of multifractal densities. The algorithm admits generalization to a multidimensional case. Analitically obtained are multifractal characteristics of the function interpolating initial data. We establish the relation between the parameter existing in the algorithm and the Levy index which is the main index for scaling function of universal multifractals.

chao-dyn↗
arXiv1997

Anomalies of Transport in Reflectionally Noninvariant Turbulence

We consider the transport of passive admixture in locally homogeneous isotropic reflectionally noninvariant turbulence of incompressible fluid. It is shown that anomalous convective flow appears which direction does not coincide with that of a mean flow.

chao-dyn↗