On the influence of plasma DBD actuator on the flow in a rectangular channel

Previously, the vortical structures generated by plasma DBD actuator working in unsteady regime were investigated in detail. The generalized model describing the behaviour of these vortices in dependency on input power parameters was introduced. This paper should reveal how the wall-jet-like-flow generated by that actuator will affect the developed flow in a rectangular channel with cross-section dimension of 250 × 100 mm. The actuator is considered in spanwise configuration where the induced flow has the same or opposite orientation as the main flow. The flow control will be tested both for steady regime and for unsteady regime. The dynamic of that complex phenomenon will be studied and results in qualitatively and quantitatively meaning will be presented. (© 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Generation of the vortex train using plasma barrier discharge actuator

The plasma actuator is used to generate periodical train of vortices moving along the surface. For generation the high-frequency high-voltage AC is used forming more-or-less steady wall-jet-like flow by the dielectric barrier discharge or corona discharge. Low-frequency modulation of the supply voltage is applied to generate vortices. Parameters of the vortex train are studied as function of the generator setting using TR-PIV technique. The generated flow patterns are to be applied for control of a boundary layer. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Cube-like structures generated by filters

The join semi-lattice of faces of an n-cube has a rich structure. In considering generalizations of these structures we are led to looking at interval algebras constructed using Boolean filters. We look at the structure of these algebras and their automorphism groups.Dedicated to the memory of Gian-Carlo Rota     

On the dynamics of a family of generated renormalization transformations

We study the family of renormalization transformations of the generalized d  -dimensional diamond hierarchical Potts model in statistical mechanic and prove that their Julia sets and non-escaping loci are always connected, where d?2$d?2$. In particular, we prove that their Julia sets can never be a Sierpiński carpet if the parameter is real. We show that the Julia set is a quasicircle if and only if the parameter lies in the unbounded capture domain of these models. Moreover, the asymptotic formula of the Hausdorff dimension of the Julia set is calculated as the parameter tends to infinity.     

Nonlinear dynamics of the dielectric elastomer actuator

As potential material for artificial muscles and haptic displays, dielectric elastomer provides large deformations with lower cost and high efficiency. The material behaves nonlinearly in both the kinematics and the constitutive relation. In this work, the nonlinear equation of motion for a dielectric elastomer actuator with a sandwich structure under constant electric potential is derived from the energy conservation condition. The equation of motion is numerically solved, and the results are discussed. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On noncompact bifurcation in one generalized model of vortex dynamics

Theoretical and Mathematical Physics - A generalized model of Hamiltonian mechanics is considered. It includes two special cases: a model of the dynamics of three magnetic vortices in ferromagnets...     

Strong interference of sound pressure generated by vortex soliton with axial flow

Sound pressure generated by a thin vortex filament with axial flow is investigated on the base of soliton theory. The pressure is estimated by using the experimental results of Maxworthy et al. [J. Fluid Mech. 151, 141] where one-soliton propagation and head-on collision of two solitons are observed. Collision of two solitons gives rise to very enhanced interference of the sound pressure.     

On the variety generated by Murskii's algebra

It is shown that the variety generated by Murskii's algebra contains uncountably many subvarieties.Presented by K. A. Baker.     

On the permutations generated by Sturmian words

Infinite permutations of use in this article were introduced in [1]. Here we distinguish the class of infinite permutations that are generated by the Sturmian words and inherit their properties. We find the combinatorial complexity of these permutations, describe their Rauzy graphs, frequencies of subpermutations, and recurrence functions. We also find their arithmetic complexity and Kamae complexity.     

Numerical analysis of the dynamics of distributed vortex configurations

A numerical algorithm is proposed for analyzing the dynamics of distributed plane vortex configurations in an inviscid incompressible fluid. At every time step, the algorithm involves the computation of unsteady vortex flows, an analysis of the configuration structure with the help of heuristic criteria, the visualization of the distribution of marked particles and vorticity, the construction of streamlines of fluid particles, and the computation of the field of local Lyapunov exponents. The inviscid incompressible fluid dynamic equations are solved by applying a meshless vortex method. The algorithm is used to investigate the interaction of two and three identical distributed vortices with various initial positions in the flow region with and without the Coriolis force.     

On the Weyl-Heisenberg frames generated by simple functions

Let with , and let (?,a,1), 0<a?1 be a Weyl-Heisenberg system {e2πimx?(x−na):m,n∈Z}. We show that if E=[0,1] (and some modulo extension of E), then (?,a,1) is a frame for each 0<a?1 (for certain a, respectively) if and only if the analytic function has no zero on the unit circle {z:|z|=1}. These results extend the case of Casazza and Kalton (2002) [6] that and a=1, which brought together the frame theory and the function theory on the closed unit disk. Our techniques of proofs are based on the Zak transform and the distribution of fractional parts of {na}_n∈Z.     

Aspects of vortex dynamics in Ginzburg-Landau models

We survey some recent work concerning the asymptotic dynamics of vortices in the 2-dimensional parabolic Ginzburg-Landau equation, the interaction of vortices with the phase field and the limiting initial value problem for both vortices and phase. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

On algebras generated by positive operators

We study algebras generated by positive matrices, i.e., matrices with nonnegative entries. Some of our results hold in more general setting of vector lattices. We reprove and extend some theorems that have been recently shown by Kandi? and ?ivic. In particular, we give a more transparent proof of their result that the unital algebra generated by positive idempotent matrices E and F such that \(E F \ge F E\) is equal to the linear span of the set \(\{I, E, F, E F, F E, E F E, F E F, (E F)^2, (F E)^2\}\), and so its dimension is at most 9. We give examples of two positive idempotent matrices that generate unital algebra of dimension 2n if n is even, and of dimension \((2n - 1)\) if n is odd. We also prove that the algebra generated by positive matrices \(B_1\), \(B_2, \ldots , B_k\) is triangularizable if \(A B_i \ge B_i A\) (\(i=1,2, \ldots , k\)) for some positive matrix A with distinct eigenvalues.