Perm State Pedagogical University
Perm', Russia
Time filter
Source Type

Kozlov N.,Perm State Pedagogical University | Salnikova A.,Perm State Pedagogical University | Stambouli M.,École Centrale Paris
61st International Astronautical Congress 2010, IAC 2010 | Year: 2010

Influence of oscillating force fields on the dynamics of two immiscible liquids of different density in a rotating cylindrical container is studied experimentally. The problem is considered from the vibrational mechanics point of view - the average dynamics of the system is investigated. In the absence of vibrations, the rotating liquids form an axisymmetric coaxial system. The two-liquid system is subject to the action of translational vibrations, longitudinal and transversal relative to the container axis, as well as transversal vibrations of circular polarization with the frequency equal to that of rotation. The latter case is modeled by rotating a horizontal container in a static force field (gravity). It is found that the oscillating force fields produce strong average effects. Under longitudinal vibrations a standing inertial wave is excited on the interface. At the relative vibration frequency increase, excitation of a space periodic axisymmetric quasi-stationary relief on the phase interface is revealed. Transversal vibrations excite circular oscillations of the light liquid column relative to the container. This is due to an azimuthal inertial wave, appearing in a resonant way. Depending on the vibration frequency, the wave propagation in the container frame occurs either in the sense of the container rotation, or in the opposite direction. In case of intensive vibrations a relief consisting of longitudinal crests is formed on the liquid-liquid interface. The ratio of vibration and rotation frequencies is one of the governing parameters for dynamics of a two-liquid system. At the vibrations of circular polarization, the excitation of azimuthal waves is observed. It also results in generation of average azimuthal motion of the liquids. At certain liquids volume ratio, auto-oscillations of the system are observed: a periodic change of the interface shape at unchanged experimental conditions. The research results are of interest for the vibrational control of multiphase systems in the micro-gravity conditions. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

Kozlov V.,École Centrale Paris | Ivanova A.,Perm State Pedagogical University | Schipitsyn V.,Perm State Pedagogical University | Stambouli M.,École Centrale Paris
Acta Astronautica | Year: 2012

The averaged lift force acting on a solid in viscous liquid in case of translational or rotary vibrations of a cavity is experimentally investigated. Experiments are performed with a heavy cylinder; different types of vibrations, translational and rotational, are investigated. It is found that the vibrations excite the mean lift force which could provide the suspension of solid even in gravity field. The repulsion lift force acts on the body near the walls of the vibrating cavity. It is caused by the viscous hydrodynamic interaction of oscillating body with the wall and is significant at a distance comparable with the thickness of Stokes layer. The intensification of vibration results in the excitation of tangential lift force, which is caused by the brake of the symmetry of the bodys oscillations with respect to the cavity wall. In case of rotary vibrations the lift force of high intensity manifests itself in the bulk of the cavity due to the interaction of body with the oscillating shear flow. The mean dynamics of the solid body in a cavity under the rotary vibrations is determined by the combined action of two averaged vibrational effects - levitation of the body in the oscillating shear flow and hydrodynamic interaction of the body with the wall. In case of translational vibrations the dynamics of the solid is mainly determined by interaction with the walls. The experiments demonstrate that the vibrations have strong mean effect on the bodies in liquid; they could be used for efficient control of solid inclusions in microgravity and must be taken into account in space experiments and technologies. © 2012 Elsevier Ltd.

Kozlov N.,Perm State Pedagogical University | Salnikova A.,Perm State Pedagogical University | Subbotin S.,Perm State Pedagogical University | Stambouli M.,École Centrale Paris
Proceedings of the International Astronautical Congress, IAC | Year: 2012

The wave processes on the surfaces of the tangential discontinuity of velocity are studied in the rotating systems. The discontinuity on the boundary of the Taylor-Proudman column is considered, the latter being formed by a light spherical body rotating with the velocity different from that of the medium. The body is free, and under the action of centrifugal force it is situated near the rotation axis of a liquid-filled cavity. In the basis of generation of the light body differential rotation is the vibrational mechanism. The body motion is excited as a result of its circular oscillations in the cavity frame of reference. The oscillations, in their turn, are induced either by the cavity vibrations in the direction perpendicular to the rotation axis, or by an external static force field. In the latter case, at the cavity rotation around the horizontal axis the gravity field is rotating in the cavity frame. Depending on the vibrational action frequency the excitation of both outstripping and lagging body rotation is possible. The development of the wave instability on the liquid column boundary (Taylor-Proudman column) is found at a certain intensity of the sphere differential rotation. It manifests itself in the azimuthal wave excitation, the crests of which are elongated parallel to the rotation axis. The study of the phase velocity, the wave number and the wave instability threshold is carried. The waves of the similar kind have been earlier found on the interface of two immiscible liquids of different density at rotation and simultaneous action of an external force. In the basis of differential rotation of the light liquid column is also the vibrational mechanism of the average shear stress generation on the media interface. The further study of this phenomenon is led. The comparative analysis is done of the results obtained in the experiments with the solid in liquid and the results obtained for the rotating two-liquid system. The focus is made upon the case of gravitational excitation. ©(2012) by the International Astronautieal Federation.

Karmanov V.N.,Russian Academy of Sciences | Zaretskaya N.E.,Russian Academy of Sciences | Lychagina E.L.,Perm State Pedagogical University
Radiocarbon | Year: 2012

By analyzing archaeological evidence and radiocarbon dates, we studied the Neolithization of Far Northeast Europe (Russian Perm' region, Komi Republic, and Nenets autonomous district). Our study shows that this process in the eastern European forest zone was rather ambiguous. Taking into account the periodicity of settling and short duration of residence here, the term "Neolithization" in its traditional sense cannot be applied to some territories in this region. For instance, the emergence of ceramics-the most important feature of Neolithization here-did not affect considerably the way of life of the ancient population, which continued the traditions of the Mesolithic hunter-gatherers well into the Early Neolithic. Such attributes as heat treatment of clay paste and siliceous rocks for changing physical features of natural materials, bifacial knapping, and construction of subterranean dwellings represent the archaeological evidence of Neolithization in the region. © 2012 by the Arizona Board of Regents on behalf of the University of Arizona.

Ilyasov R.A.,Russian Academy of Sciences | Kutuev I.A.,Russian Academy of Sciences | Petukhov A.V.,Perm State Pedagogical University | Poskryakov A.V.,Russian Academy of Sciences | Nikolenko A.G.,Russian Academy of Sciences
Journal of Apicultural Science | Year: 2011

A mitochondrial DNA region covering 5'-end of the gene of the second subunit NADH dehydrogenase (ND2), was PCR amplifi ed in Dark European Honeybees Apis mellifera mellifera from the Urals (Russia) region and in the presumed Apis mellifera macedonica from the Ukraine. Phylogenetic analysis of sequenced DNA samples with GenBank ( data showed the existence of four evolutionary branches where the Ural honeybees were grouped with European A. m. mellifera, and Ukrainian honeybees with European A. m. macedonica. These results suggest the genetic relationship of the Russian Urals and the European populations of A. m. mellifera. These data have allowed us to put forward the hypothesis that the subspecies A. m. mellifera, is a unique specimen of evolutionary branch M.

Bratsun D.A.,Perm State Pedagogical University | De Wit A.,Free University of Colombia
Chemical Engineering Science | Year: 2011

Buoyancy-driven convection can be induced by concentration and temperature gradients near the interface between two immiscible fluids filling a vertical Hele-Shaw cell, each of them containing a reactant of an exothermic A+B → C reaction taking place in the bulk of the lower layer. A chemo-hydrodynamical pattern appears then due to the combined action of Rayleigh-Taylor, diffusive layer convection and Rayleigh-Bénard instabilities occurring either below or above the interface. The mathematical model we develop to describe such dynamics consists in a set of reaction-diffusion-advection equations ruling the evolution of concentrations and temperature coupled to Navier-Stokes equation, written in a Hele-Shaw approximation. We perform numerical simulations of the non-linear system and study the influence on pattern formation of changes in the Damköhler number of the problem and in the ratio of initial reactant concentrations. © 2011 Elsevier Ltd.

Eremin E.A.,Perm State Pedagogical University
8th IEEE International Conference on Application of Information and Communication Technologies, AICT 2014 - Conference Proceedings | Year: 2014

Paper proposes new ideas about assessment of conceptual knowledge, obtained after digestion of a learning course. It offers original way to evaluate an educational success, which is based on the analysis of concepts' interrelations: students who mastered a material better, must demonstrate more linked structure of knowledge. Formal assessment procedure was developed; its experimental assay showed the existence of accordance between the proposed quantitative gauge and conventional teacher's marks. So considered method may be useful for final control to verify how student has digested a large complete portion of content during e-learning process.

Dyakova V.,Perm State Pedagogical University | Kozlov V.,Perm State Pedagogical University | Polezhaev D.,Perm State Pedagogical University
Shock and Vibration | Year: 2014

The paper focuses on the experimental study of the dynamics of liquid and granular medium in a rapidly rotating horizontal cylinder. In the cavity frame gravity field performs rotation and produces oscillatory liquid flow, which is responsible for the series of novel effects; the problem corresponds to "vibrational mechanics" - generation of steady flows and patterns by oscillating force field. The paper presents the initial results of experimental study of a novel pattern formation effect which is observed at the interface between fluid and sand and which takes the form of ripples extended along the axis of rotation. The initial results of experimental research of a novel effect of pattern formation at the interface between fluid and sand in the form of ripples extended along the axis of rotation are presented. The spatial period of the patterns is studied in dependence on liquid volume, viscosity, and rotation rate. The experimental study of long time dynamics of pattern formation manifests that regular ripples transform into a series of dunes within a few minutes or dozens of minutes. The variety of patterns is determined by the interaction of two types of liquid flows induced by gravity: oscillatory and steady azimuthal flows near the sand surface. © 2014 Veronika Dyakova et al.

Gordeeva V.Y.,Perm State Pedagogical University | Lyushnin A.V.,Perm State Pedagogical University
European Physical Journal: Special Topics | Year: 2013

A thin film of an evaporating polar liquid on a solid substrate is investigated within the framework of the lubrication theory. Using linear analysis, we have found that stability of the film depends only on two control parameters: the evaporation and Maranagoni numbers. We demonstrate that the Marangoni effect plays a destabilizing role while evaporation stabilizes the film. © 2013 EDP Sciences and Springer.

Gordeeva V.Y.,Perm State Pedagogical University | Lyushnin A.V.,Perm State Pedagogical University
Technical Physics | Year: 2013

We consider the dynamics of evaporation of a thin layer of a polar liquid (e. g., water) with the free surface, which is located on a solid substrate. Thermocapillary instability takes place at the liquid-vapor free boundary. The surface energy of the substrate-liquid contact region is a nonmonotonic function and is the sum of the interactions of the Van der Waals force and the force of the double electric layer. The influence of the Marangoni effect on the velocity, profile, and stability of the liquid evaporation front is analyzed. © 2013 Pleiades Publishing, Ltd.

Loading Perm State Pedagogical University collaborators
Loading Perm State Pedagogical University collaborators