Труды сотрудников ИВМ СО РАН

[Text] : статья / A.N. Gorban [et al.] // Physica A. - 1996. - 231. - p. 648-672
   Перевод заглавия: Траектории релаксации: глобальная аппроксимация
Аннотация: The paper intends to fill the gap of analytic approximate methods for non-linear space-independent dissipative systems equipped with the entropy functional. The key point of the analysis is an upper limiting state in the beginning of the relaxation. Extremal properties of this state are described and explicit estimations are derived. This limiting state is used to construct explicit approximations of the phase trajectories. Special attention is paid to accomplish positiv-ity, smoothness and the entropy growth along the approximate trajectories. The method is tested for the space-independent Boltzmann equation with various collisional mechanisms.

http://icm.krasn.ru/refextra.php?id=2092,
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ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

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Gorban, A.N.; Горбань, Александр Николаевич; Karlin, I.V.; Карлин, Илья Вениаминович; Nonnenmacher, T.F.; Zmievskii, V.B.; Змиевский В.Б.

[Text] : статья / G.G. Krushenko // Вестник СибГАУ. - 2010. - Вып. 3(29). - p. 158-160
   Перевод заглавия: Испытание механических свойств алюминиево-кремниевых сплавов на отдельно отлитых образцах

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Крушенко, Генрих Гаврилович

[Text] : тезисы / V. M. Lugovoy, M. G. Sadovskii, E. A. Temlyakova // Functional Genomics. Next Generation Applications & Technologies. - 2011. - p. 91


Доп.точки доступа:
Sadovskii, M.G.; Садовский, Михаил Георгиевич; Temlyakova , E.A.

[Текст] : статья / I.I. Ryzhkov // Lournal of Applied Mechanics and Technical Physics. - 2011. - Vol. 52, Iss. 4. - p. 560-570DOI 10.1134/S0021894411040080 . -
Аннотация: A model of vibrational convection of a binary mixture with the thermodiffusion effect is considered. The symmetries of model equations are found, depending on the values of physical parameters. A partially invariant solution, which describes separation of the binary mixture in a thermodiffusion column, is constructed and studied. The influence of streamwise vibrations on the flow regime and separation of the mixture is investigated.

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Доп.точки доступа:
Stepanova, I.V.; Степанова, Ирина Владимировна; Рыжков, Илья Игоревич

[Text] : статья / G.G. Krushenko // Вестник СибГАУ. - 2012. - Вып. 2(42). - p. 135-136
   Перевод заглавия: Математическое моделирование механических свойств конструкционных сталей

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ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Крушенко, Генрих Гаврилович

/ C. J. Farrugia [et al.] // Sol. Phys. - 2012. - Vol. 281, Is. 1. - pp. 461-489, DOI 10.1007/s11207-012-0119-1. - Cited References: 53 . - 29. - ISSN 0038-0938РУБ Astronomy & Astrophysics

Аннотация: We discuss the temporal variations and frequency distributions of solar wind and interplanetary magnetic field parameters during the solar minimum of 2007-2009 from measurements returned by the IMPACT and PLASTIC instruments on STEREO-A. We find that the density and total field strength were significantly weaker than in the previous minimum. The Alfv,n Mach number was higher than typical. This reflects the weakness of magnetohydrodynamic (MHD) forces, and has a direct effect on the solar wind-magnetosphere interactions. We then discuss two major aspects that this weak solar activity had on the magnetosphere, using data from Wind and ground-based observations: i) the dayside contribution to the cross-polar cap potential (CPCP), and ii) the shapes of the magnetopause and bow shock. For i) we find a low interplanetary electric field of 1.3 +/- 0.9 mV m(-1) and a CPCP of 37.3 +/- 20.2 kV. The auroral activity is closely correlated to the prevalent stream-stream interactions. We suggest that the Alfven wave trains in the fast streams and Kelvin-Helmholtz instability were the predominant agents mediating the transfer of solar wind momentum and energy to the magnetosphere during this three-year period. For ii) we determine 328 magnetopause and 271 bow shock crossings made by Geotail, Cluster 1, and the THEMIS B and C spacecraft during a three-month interval when the daily averages of the magnetic and kinetic energy densities attained their lowest value during the three years under survey. We use the same numerical approach as in Fairfield's (J. Geophys. Res. 76, 7600, 1971) empirical model and compare our findings with three magnetopause models. The stand-off distance of the subsolar magnetopause and bow shock were 11.8 R-E and 14.35 R-E, respectively. When comparing with Fairfield's (1971) classic result, we find that the subsolar magnetosheath is thinner by similar to 1 R-E. This is mainly due to the low dynamic pressure which results in a sunward shift of the magnetopause. The magnetopause is more flared than in Fairfield's model. By contrast the bow shock is less flared, and the latter is the result of weaker MHD forces.

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Farrugia, C.J.; Harris, B.; Leitner, M.; Mostl, C.; Galvin, A.B.; Simunac, K.D.C.; Torbert, R.B.; Temmer, M.B.; Veronig, A.M.; Erkaev, N.V.; Еркаев, Николай Васильевич; Szabo, A.; Ogilvie, K.W.; Luhmann, J.G.; Osherovich, V.A.

/ A. Divin [et al.] // J. Geophys. Res-Space Phys. - 2012. - Vol. 117. - Ст. A06217, DOI 10.1029/2011JA017464. - Cited References: 43. - The present work is supported partially by the Onderzoekfonds KU Leuven (Research Fund KU Leuven), by the NASA MMS grant NNX08AO84G and by the European Commission's Seventh Framework Programme (FP7/2007-2013) under the grant agreement 263340 (SWIFF project, www. swiff. eu) and 269198 - Geoplasmas (Marie Curie International Research Staff Exchange Scheme). Additional support is provided by RFBR grants 09-05-91000-ANF-a, 12-05-00152-a and 12-05-00918-a, Austrian Science Fund project T193-N16 and by SPSU grants 11.38.47.2011 and 11.38.84.2012. The simulations were conducted on the resources of the Vlaams Supercomputer Centrum (VSC) at the Katholieke Universiteit Leuven. The authors wish to thank the reviewers for their comments that helped to improve the manuscript. . - ISSN 2169-9380РУБ Astronomy & Astrophysics

Аннотация: The Sweet-Parker analysis of the inner electron diffusion region of collisionless magnetic reconnection is presented. The study includes charged particles motion near the X-line and an appropriate approximation of the off-diagonal term for the electron pressure tensor. The obtained scaling shows that the width of the inner electron diffusion region is equal to the electron inertial length, and that electrons are accelerated up to the electron Alfven velocity in X-line direction. The estimated effective plasma conductivity is based on the electron gyrofrequency rather than the binary collision frequency, and gives the extreme (minimal) value of the plasma conductivity similar to Bohm diffusion. The scaling properties are verified by means of Particle-in-Cell simulations. An ad hoc parameter needs to be introduced to the scaling relations in order to better match the theory and simulations.


Доп.точки доступа:
Divin, A.; Lapenta, G.; Markidis, S.; Semenov, V.S.; Erkaev, N.V.; Еркаев, Николай Васильевич; Korovinskiy, D.B.; Biernat, H.K.

/ V. M. Sadovskii, O. V. Sadovskaya ; ed. by T.E.Simos [et al.] // NUMERICAL ANALYSIS AND APPLIED MATHEMATICS (ICNAAM 2012), VOLS A AND B. Ser. AIP Conference Proceedings : AMER INST PHYSICS, 2012. - Vol. 1479: International Conference of Numerical Analysis and Applied Mathematics (ICNAAM) (SEP 19-25, 2012, Kos, GREECE). - pp. 1611-1614, DOI 10.1063/1.4756474. - Cited References: 4 . - ISBN 0094-243X. - ISBN 978-0-7354-1091-6РУБ Mathematics, Applied + Physics, Applied

Аннотация: Parallel program systems for numerical solution of 2D and 3D problems of the dynamics of deformable media with constitutive relationships of rather general form on the basis of universal mathematical model describing small strains of elastic, elastic-plastic and granular materials are worked out. Some computations of dynamic problems with and without taking into account the moment properties of a material were performed on supercomputers with cluster architecture.

РИНЦ


Доп.точки доступа:
Sadovskii, V.M.; Садовский, Владимир Михайлович; Sadovskaya, O.V.; Садовская, Оксана Викторовна; Simos, T.E. \ed.\; Psihoyios, G. \ed.\; Tsitouras, C. \ed.\

/ A.V. Lapko, V.A. Lapko // Optoelectronics, Instrumentation and Data Processing. - 2012. - Vol. 48, Is. 4. - pp. 416-422, DOI 10.3103/S8756699012040139 . - ISSN 8756-6990
Аннотация: Asymptotic properties of a nonparametric estimate of the separating surface equation defined in the space of independent attributes of classified objects are studied. Based on this analysis, the importance of the influence of a priori information about independence of random variables on the approximation properties of the nonparametric decision function in a two-alternative problem of pattern recognition is established. В© 2012 Allerton Press, Inc.

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Доп.точки доступа:
Lapko, V.A.; Лапко, Василий Александрович; Лапко, Александр Васильевич

[Text] / M.P. Varygina, O.V. Sadovskaya, V.M. Sadovskii // J. Appl. Mech. Tech. Phys. - 2010. - Vol. 51, Is. 3. - pp. 405-413, DOI 10.1007/s10808-010-0055-5. - Cited References: 9. - This work was supported by the Russian Foundation for Basic Research (Grant No. 08-01-00148), the Complex Program of Basic Research of the Presidium of the Russian Academy of Sciences No. 2 Intelligent information technologies, mathematical modeling, system analysis and automation, and the interdisciplinary Integration project of the Siberian Division of the Russian Academy of Sciences No. 40. . - ISSN 0021-8944РУБ Mechanics + Physics, Applied

Аннотация: Using highly effective parallel calculations, it is shown that in a moment elastic medium, there is a resonant frequency which corresponds to the eigenfrequency of rotational motion of particles and does not depend on the size of the region studied.


Доп.точки доступа:
Varygina, M.P.; Варыгина, Мария Петровна; Sadovskaya, O.V.; Садовская, Оксана Викторовна; Sadovskii, V.M.; Садовский, Владимир Михайлович

[Text] / E. N. Vasil'ev // Tech. Phys. - 2013. - Vol. 58, Is. 10. - P1420-1425, DOI 10.1134/S1063784213100277. - Cited References: 6 . - ISSN 1063-7842РУБ Physics, Applied

Аннотация: The temperature as well as specific and integrated powers of energy mechanisms for sustaining a steady equilibrium arc discharge in a cylindrical channel in argon and carbon dioxide under atmospheric pressure are determined by solving the Elenbaas-Heller equation for various values of current I and radius R. The results of computations are represented in the form of state diagrams intended for estimating the main energy parameters of electric arcs for preset values of I and R. For carbon dioxide, the effect of screening of the heat conduction mechanism at the discharge boundary, which is due to a peculiar temperature dependence of radiation properties, is detected.

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Vasil'ev, E. N.; Васильев, Евгений Николаевич

/ O. V. Sadovskaya // Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics). - 2013. - Vol. 8236 LNCS: 5th International Conference on Numerical Analysis and Applications, NAA 2012 (15 June 2013 through 20 June 2013, Lozenetz. - P471-478, DOI 10.1007/978-3-642-41515-9_53 . -
Аннотация: Parallel program systems for numerical solution of 2D and 3D problems of the dynamics of deformable media with constitutive relationships of rather general form on the basis of universal mathematical model describing small strains of elastic, elastic-plastic and granular materials are worked out. Computational algorithm is based on the splitting methods with respect to physical processes and spatial variables. Some computations of dynamic problems with and without taking into account the moment properties of a material were performed on clusters. В© 2013 Springer-Verlag.

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Institute of Computational Modeling SB RAS, Akademgorodok 50/44, 660036 Krasnoyarsk, Russian Federation

Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна

/ V. M. Sadovskii, O. V. Sadovskaya // Physical Mesomechanics. - 2013. - Vol. 16, № 4. - P312-318, DOI 10.1134/S102995991304005X . - ISSN 1029-9599
Аннотация: Based on dynamic equations of a heterogeneous elastic medium which take into account rotational degrees of freedom of microstructure particles, a simplified mathematical model was constructed to describe the wave motions of a nematic liquid crystal under weak mechanical and temperature perturbations. It is shown that in the medium under plane deformation, the tangential stress obeys the Klein-Gordon equation of oscillatory particle rotation. Consideration is given to the possibility of initiating rotational waves in a nematic liquid crystal, which change its optical properties, due to heat sources acting at its boundary. © 2013 Pleiades Publishing, Ltd.

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ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Sadovskaya, O.V.; Садовская, Оксана Викторовна; Sadovsky V.M.

[Text] : статья / V.K. Andreev // Proceeding of the Steklov Institute of Mathematics. - 2008. - Suppl. 1. - p. 1-4


Доп.точки доступа:
Андреев, Виктор Константинович

[Text] : статья / A. Bardow, I. V. Karlin, A. A. Gusev // Physical review E. - 2008. - Vol. 77. - Ст. 025701, DOI 10.1103/PhysRevE.77.025701 . - ISSN 1539-3755
Аннотация: The lattice Boltzmann method is a highly promising approach to the simulation of complex flows. Here, we realize recently proposed multispeed lattice Boltzmann models [S. Chikatamarla et al., Phys. Rev. Lett. 97 190601 (2006)] by exploiting the flexibility offered by off-lattice Boltzmann methods. The approach is based on the general characteristic-based algorithm for off-lattice Boltzmann simulations that preserves all appealing properties of the standard lattice Boltzmann method while extending the method to unstructured grids. We show that the use of multispeed models indeed gives rise to major improvements in accuracy. The suggested approach thus renders truly large-scale off-lattice Boltzmann computations practical.

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Karlin, I.V.; Карлин, Илья Вениаминович; Gusev, A.A.

[Text] : статья / R. A. Brownlee, A. N. Gorban, J. Levesley // Physica A. - 2008. - Vol. 387, Iss. 2-3. - p. 385-406DOI 10.1016/j.physa.2007.09.031 . -
Аннотация: We construct a system of nonequilibrium entropy limiters for the lattice Boltzmann methods (LBM). These limiters erase spurious oscillations without blurring of shocks, and do not affect smooth solutions. In general, they do the same work for LBM as flux limiters do for finite differences, finite volumes and finite elements methods, but for LBM the main idea behind the construction of nonequilibrium entropy limiter schemes is to transform a field of a scalar quantity - nonequilibrium entropy. There are two families of limiters: (i) based on restriction of nonequilibrium entropy (entropy "trimming") and (ii) based on filtering of nonequilibrium entropy (entropy filtering). The physical properties of LBM provide some additional benefits: the control of entropy production and accurate estimate of introduced artificial dissipation are possible. The constructed limiters are tested on classical numerical examples: 1D athermal shock tubes with an initial density ratio 1:2 and the 2D lid-driven cavity for Reynolds numbers Re between 2000 and 7500 on a coarse 100*100 grid. All limiter constructions are applicable for both entropic and non-entropic quasiequilibria.

Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Gorban, A.N.; Горбань, Александр Николаевич; Levesley, J.

[Text] / N. V. Erkaev [et al.] // COORDINATED MEASUREMENTS OF MAGNETOSPHERIC PROCESSES. Ser. ADVANCES IN SPACE RESEARCH : PERGAMON PRESS LTD, 2000. - Vol. 25: D0 1 Symposium of COSPAR Scientific Commission D Held at the 32nd COSPAR Scientific Assembly (JUL 12-19, 1998, NAGOYA, JAPAN), Is. 07.08.2013. - P1523-1528, DOI 10.1016/S0273-1177(99)00665-1. - Cited References: 18 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: We extend our "magnetic string" MHD model describing the flow of the shocked solar wind around the magnetosphere to include an anisotropic plasma pressure with p(perpendicular to) p(parallel to). Thermodynamic properties are determined by the law of conservation of energy of a magnetic string associated with a magnetic field line. The MHD equations are closed by a relation between p(perpendicular to) and p(parallel to) corresponding to the threshold of the electromagnetic proton cyclotron wave instability. Assuming no flow across the magnetopause, we compare profiles of the steady-state magnetic field and plasma parameters along the subsolar line for upstream sonic and Alfven Mach numbers = 10 with the isotropic case (p(perpendicular to) = p(parallel to)). In the anisotropic model, besides the density, both temperatures, plasma pressures and betas decrease toward the magnetopause. The temperature and plasma pressure parallel to the magnetic field decrease more strongly than those perpendicular to the field. Profiles for temperature and pressure in the case of isotropy lie between those of corresponding parallel and perpendicular values, but closer to the latter. The gradient of B near the magnetopause is larger than for isotropic pressure. (C) 2000 COSPAR. Published by Elsevier Science Ltd.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Farrugia, C.J.; Biernat, H.K.; Ogilvie, K.W.; Quinn, J.M.

[Text] : статья / A. N. Gorban, O. Radulescu // Advances in Chemical Engineering. - 2008. - Vol. 34 . - p. 103-173DOI 10.1016/S0065-2377(08)00003-3 . -
Аннотация: The concept of the limiting step gives the limit simplification: the whole network behaves as a single step. This is the most popular approach for model simplification in chemical kinetics. However, in its elementary form this idea is applicable only to the simplest linear cycles in steady states. For simple cycles the nonstationary behavior is also limited by a single step, but not the same step that limits the stationary rate. In this chapter, we develop a general theory of static and dynamic limitation for all linear multiscale networks. Our main mathematical tools are auxiliary discrete dynamical systems on finite sets and specially developed algorithms of “cycles surgery” for reaction graphs. New estimates of eigenvectors for diagonally dominant matrices are used. Multiscale ensembles of reaction networks with well-separated constants are introduced and typical properties of such systems are studied. For any given ordering of reaction rate constants the explicit approximation of steady state, relaxation spectrum and related eigenvectors (“modes”) is presented. In particular, we prove that for systems with well-separated constants eigenvalues are real (damped oscillations are improbable). For systems with modular structure, we propose the selection of such modules that it is possible to solve the kinetic equation for every module in the explicit form. All such “solvable” networks are described. The obtained multiscale approximations, that we call “dominant systems” are computationally cheap and robust. These dominant systems can be used for direct computation of steady states and relaxation dynamics, especially when kinetic information is incomplete, for design of experiments and mining of experimental data, and could serve as a robust first approximation in perturbation theory or for preconditioning.

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Radulescu, O.; Горбань, Александр Николаевич

[Текст] : статья / V.I. Senashov // Journal of Siberian Federal University. Mathematics & Physics = Журнал Сибирского федерального университета. Математика и физика. - 2009. - Т. 2, № 3. - С. 279-287
Аннотация: In the paper we review the results characterizing layer-finite groups and almost layer-finite groups in the class of all groups. We also characterize the groups with layer-finite periodic parts, the groups with almost layer-finite periodic parts and the groups with generalized Chernikov periodic parts. Theorems describing the properties of quasi-layer-finite groups and simple quasi-layer-finite groups are provided.

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ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

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Сенашов, Владимир Иванович

[Text] / V. K. Andreev // Differ. Equ. - 2011. - Vol. 47, Is. 5. - P671-680, DOI 10.1134/S0012266111050065. - Cited References: 6. - The research was supported by the Russian Foundation for Basic Research (project no. 08-01-00762) and by Interscience Integration Project 116 of the Siberian Branch of the Russian Academy of Sciences. . - ISSN 0012-2661РУБ Mathematics

Аннотация: For the Navier-Stokes equations, we study a solution invariant with respect to a oneparameter group and modeling a nonstationary motion of two viscous fluids in a cylindrical tube; the fluid layer near the tube wall can be viewed as a lubricant. The motion is due to a nonstationary pressure drop. We obtain a priori estimates for the velocities in the layers. We find a stationary state of the system and show that it is the limit state as t - a provided that the pressure gradient in one of the fluids stabilizes with time. We solve the inverse problem of finding the pressure gradients and the velocity field from a known flow rate.


Доп.точки доступа:
Андреев, Виктор Константинович