Yaroslavl State Technical University

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Simakov N.N.,Yaroslavl State Technical University
Technical Physics | Year: 2017

A numerical experiment on the simulation of the two-phase flow formed during spraying of a liquid by a nozzle has been described. The radial and axial velocity profiles of the droplets and gas in the free spray and in the two-phase flow through a cylindrical apparatus have been calculated and represented taking into account the early drag crisis of droplets and peculiarities of turbulent friction in the gas, which was detected in previous experiments. The distinguishing feature of the numerical model of the two-phase flow is that it employs the differential equations describing the nonstationary flow of a compressible gas as the initial equations. In transition to their difference analog, the familiar Lax–Wendorff algorithm has been used. A comparison of the results of calculations based on this model with experimental data has demonstrated their concordance. © 2017, Pleiades Publishing, Ltd.


Simakov N.N.,Yaroslavl State Technical University
Technical Physics | Year: 2016

A numerical experiment on the simulation of heat transfer from a sphere to a gas flow in a cylindrical channel in the Stokes and transient flow regimes has been described. Radial and axial profiles of the gas temperature and the dependences of drag coefficient Cd of the body and Nusselt number Nu on Reynolds number Re have been calculated and analyzed. The problem of the influence of the early drag crisis for a sphere on its heat transfer to the gas flow has been considered. The estimation of this phenomenon has shown that the early drag crisis of the sphere in a strongly turbulent flow causes a reduction in heat transfer from the sphere to the gas by three to six times (in approximately the same proportion as for its drag coefficient). © 2016, Pleiades Publishing, Ltd.


Simakov N.N.,Yaroslavl State Technical University
Technical Physics | Year: 2016

An early drag crisis can occur at high turbulence of incoming gas flow to a sphere. To study the influence of a crisis on heat transfer from a sphere to gas, a numerical experiment was carried out in which the free gas flow around a sphere with a temperature lower than the sphere temperature was simulated for two cases. The flow was laminar in the first case and highly turbulent in the second case. To take into account turbulence, the kinematic coefficient of turbulent viscosity with a value, which is much higher (up to 2000 times) than that for physical viscosity, was introduced. The results of calculations show that the early drag crisis occurs at Reynolds numbers of about 100 and results in considerable (by four to seven times) decrease in the hydrodynamic force and sphere drag coefficient Cd. The early drag crisis is also accompanied by the crisis of heat transfer from a sphere to gas with a decrease in Nusselt numbers Nu by three to six times. © 2016, Pleiades Publishing, Ltd.


Zalutskii A.A.,Yaroslavl State Technical University
Journal of Surface Investigation | Year: 2014

Experimental results on studying charge exchange in iron ions in systems of reduced dimensionality (nanoclays) of natural origin is presented. The conditions for the observation and the effect of different external factors on the reversible transition of the valence change for iron ions (Fe3+⇄Fe2+) in typical representatives of clays is established using Mössbauer spectroscopy. A technique of the determination of the location of iron complexes on the aluminosilicate surface of clays for Earth group planets is developed. © Pleiades Publishing, Ltd., 2014.


Zalutski A.A.,Yaroslavl State Technical University
Protection of Metals and Physical Chemistry of Surfaces | Year: 2016

Using a technique that is developed using Mössbauer spectroscopy, parameters of the diffusion motion and data on geography of the exchangeable iron complexes on a silica–alumina surface of clays were presented. The analyzed natural causes of the temperature behavior of the dynamic Mössbauer parameters allowed the pattern of the atoms' motion to be determined on the basis of various models of diffusion motion. For iron atoms adsorbed in the interwrapper space of the mineral, a jumplike translational diffusion is typical, which allowed determination of the sizes of the fluctuation hollow (r ~ 0.16 nm) necessary for the diffusion of atoms. A nonisotropic character of the diffusion for the interlayer and surface iron atoms caused by structural anisotropy of a clay substrate and by the structure of the iron complexes themselves was found. The surface diffusion of iron dimers occurs in a bounded area (L ~ 0.25 nm) and is rotational. © 2016, Pleiades Publishing, Ltd.


Ivanov P.A.,Yaroslavl State Technical University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

There are presented results of scaled image recognition modeling with the help of optical correlator with invariant correlation filters like MACE, GMACE, MINACE and DCCF. The image database for testing include images of true and false classes. There are presented qualitative and quantitative characteristics of output correlation peaks. Also there is provided an analysis of positive and negative side of each filter's type as for single class only scaled images recognition so for multiclass one. Also there are shown results for modeling of images with more complex distortions recognition using all mentioned types of filters. © 2014 Copyright SPIE.


Poroyko T.A.,Yaroslavl State Technical University | Skurygin E.F.,Yaroslavl State Technical University
Journal of Physics: Conference Series | Year: 2014

The non-steady-state process of a gas absorption by initially motionless liquid is investigated. Nonlinear analysis of the thermo-capillary instability showed that the transition of the process to unstable convective regime is determined by two sharply different characteristic times. First one is the time of neutral perturbations, when the fluctuations of the concentration of absorbable substance, temperature and the liquid velocity stop decrease and begin to grow together, but their intensity is too small to influence on the absorption rate. The second one is the time much greater than the first, when the perturbations reach sufficient values, and the absorption process turns to the convective regime. The results obtained explain the well-known experimental data on delaying of the transition of the absorption process to the unstable convective regime.


Ivanov P.A.,Yaroslavl State Technical University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

The presented paper deals to PC modeling of scaled and rotated images recognition based on different types of distortion invariant correlation filters. There was used a database of different images (both false and true class) that are under geometrical distortions and there were calculated correlation outputs for images recognition with the help of MACE, MINACE, GMACE, DCCF and polynomial filters and it's combinations for two-stage recognition. The results provide a possibility for successful usage of implemented algorithms. © 2016 SPIE.


Kostyuchenko M.V.,Yaroslavl State Technical University
Solid State Phenomena | Year: 2015

The technique of finite difference equations is used for analytical investigation of magnetization pattern in magnetic multilayers. The magnetic multilayers with equal magnetic layers and ferrimagnetic multilayers are considered. Heisenberg and biquadratic exchange interactions and uniaxial anisotropy are taken into account. The analytical dependencies of total magnetic moment on external magnetic field are obtained taking into account the strong interaction with the substrate. The significant difference in the behavior of magnetic moment is derived for ferrimagnetic multilayers with odd and even layers number. © (2015) Trans Tech Publications, Switzerland.


Ivanov P.A.,Yaroslavl State Technical University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

The presented paper is of PC modeling of scaled object recognition with the help of invariant correlation filters for optical correlators. The object database consists of objects of true and false classes with different changes of scale. The recognition process consits of two stages-multiclass recognition and geometrical change recognition with the help of filters of different types. The results of modeling present data on comparison of different combination of filter types. © 2015 SPIE.

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