5,073 research outputs found
Fractional dynamics of systems with long-range interaction
We consider one-dimensional chain of coupled linear and nonlinear oscillators
with long-range power wise interaction defined by a term proportional to
1/|n-m|^{\alpha+1}. Continuous medium equation for this system can be obtained
in the so-called infrared limit when the wave number tends to zero. We
construct a transform operator that maps the system of large number of ordinary
differential equations of motion of the particles into a partial differential
equation with the Riesz fractional derivative of order \alpha, when 0<\alpha<2.
Few models of coupled oscillators are considered and their synchronized states
and localized structures are discussed in details. Particularly, we discuss
some solutions of time-dependent fractional Ginzburg-Landau (or nonlinear
Schrodinger) equation.Comment: arXiv admin note: substantial overlap with arXiv:nlin/051201
Oscillation of a time fractional partial differential equation
We consider a time fractional partial differential equation subject to the Neumann boundary condition. Several sufficient conditions are established for oscillation of solutions of such equation by using the integral averaging method and a generalized Riccati technique. The main results are illustrated by examples
FORCED OSCILLATION FOR A CLASS OF FRACTIONAL PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS
We investigate the oscillation of class of time fractional partial dierential equationof the formfor (x; t) 2 R+ = G; R+ = [0;1); where is a bounded domain in RN with a piecewisesmooth boundary @ ; 2 (0; 1) is a constant, D +;t is the Riemann-Liouville fractional derivativeof order of u with respect to t and is the Laplacian operator in the Euclidean N- space RNsubject to the Neumann boundary conditionWe will obtain sucient conditions for the oscillation of class of fractional partial dierentialequations by utilizing generalized Riccatti transformation technique and the integral averagingmethod. We illustrate the main results through examples
Hamiltonian formalism of fractional systems
In this paper we consider a generalized classical mechanics with fractional
derivatives. The generalization is based on the time-clock randomization of
momenta and coordinates taken from the conventional phase space. The fractional
equations of motion are derived using the Hamiltonian formalism. The approach
is illustrated with a simple-fractional oscillator in a free state and under an
external force. Besides the behavior of the coupled fractional oscillators is
analyzed. The natural extension of this approach to continuous systems is
stated. The interpretation of the mechanics is discussed.Comment: 16 pages, 5 figure
Periodically Forced Nonlinear Oscillators With Hysteretic Damping
We perform a detailed study of the dynamics of a nonlinear, one-dimensional
oscillator driven by a periodic force under hysteretic damping, whose linear
version was originally proposed and analyzed by Bishop in [1]. We first add a
small quadratic stiffness term in the constitutive equation and construct the
periodic solution of the problem by a systematic perturbation method,
neglecting transient terms as . We then repeat the
analysis replacing the quadratic by a cubic term, which does not allow the
solutions to escape to infinity. In both cases, we examine the dependence of
the amplitude of the periodic solution on the different parameters of the model
and discuss the differences with the linear model. We point out certain
undesirable features of the solutions, which have also been alluded to in the
literature for the linear Bishop's model, but persist in the nonlinear case as
well. Finally, we discuss an alternative hysteretic damping oscillator model
first proposed by Reid [2], which appears to be free from these difficulties
and exhibits remarkably rich dynamical properties when extended in the
nonlinear regime.Comment: Accepted for publication in the Journal of Computational and
Nonlinear Dynamic
Numerical Investigation of the Fractional Oscillation Equations under the Context of Variable Order Caputo Fractional Derivative via Fractional Order Bernstein Wavelets
This article describes an approximation technique based on fractional order
Bernstein wavelets for the numerical simulations of fractional oscillation
equations under variable order, and the fractional order Bernstein wavelets are
derived by means of fractional Bernstein polynomials. The oscillation equation
describes electrical circuits and exhibits a wide range of nonlinear dynamical
behaviors. The proposed variable order model is of current interest in a lot of
application areas in engineering and applied sciences. The purpose of this
study is to analyze the behavior of the fractional force-free and forced
oscillation equations under the variable-order fractional operator. The basic
idea behind using the approximation technique is that it converts the proposed
model into non-linear algebraic equations with the help of collocation nodes
for easy computation. Different cases of the proposed model are examined under
the selected variable order parameters for the first time in order to show the
precision and performance of the mentioned scheme. The dynamic behavior and
results are presented via tables and graphs to ensure the validity of the
mentioned scheme. Further, the behavior of the obtained solutions for the
variable order is also depicted. From the calculated results, it is observed
that the mentioned scheme is extremely simple and efficient for examining the
behavior of nonlinear random (constant or variable) order fractional models
occurring in engineering and science.Comment: This is a preprint of a paper whose final and definite form is
published Open Access in 'Mathematics' at
[http://dx.doi.org/10.3390/math11112503
Differential/Difference Equations
The study of oscillatory phenomena is an important part of the theory of differential equations. Oscillations naturally occur in virtually every area of applied science including, e.g., mechanics, electrical, radio engineering, and vibrotechnics. This Special Issue includes 19 high-quality papers with original research results in theoretical research, and recent progress in the study of applied problems in science and technology. This Special Issue brought together mathematicians with physicists, engineers, as well as other scientists. Topics covered in this issue: Oscillation theory; Differential/difference equations; Partial differential equations; Dynamical systems; Fractional calculus; Delays; Mathematical modeling and oscillations
Combustion instabilities: mating dance of chemical, combustion, and combustor dynamics
Combustion instabilities exist as consequences of
interactions among three classes of phenomena: chemistry and chemical dynamics; combustion dynamics; and combustor dynamics. These dynamical processes take place simultaneously in widely different spatial scales characterized by lengths roughly in the ratios (10^(-3)
- 10^(-6)):1:(10^3-10^6). However, due to the wide differences in the associated characteristic velocities, the corresponding time scales are all close. The instabilities in question are observed as oscillations having a time scale in the range of natural acoustic oscillations. The apparent dominance of that single macroscopic time scale must not be permitted to obscure the fact that the relevant physical processes occur on three disparate length scales. Hence, understanding combustion instabilities at the practical level of design and successful operation is ultimately based on understanding three distinct sorts of dynamics
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