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Найдено документов в текущей БД: 5

    On electric field penetration from ground into the ionosphere
[Text] : статья / V.V. Denisenko [et al.] // J. Atmos. Sol.-Terr. Phys. - 2013. - Vol. 102. - P341-353, DOI 10.1016/j.jastp.2013.05.019. - Cited References: 29. - This work is supported by Grants 09-06-91000, 12-05-00152 from the Russian Foundation for Basic Research. Additional support is due to the Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" under Project I193-N16 and the "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences. The authors are grateful to the unknown reviewers for the fruitful detailed discussion. . - 13. - ISSN 1364-6826
РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: A quasi stationary three dimensional model of electric fields and currents in the conductor that includes the Earth's atmosphere and ionosphere is created. The results of the three dimensional model are simpler regarding interpretation and explanation than two dimensional ones. Known approaches regarding the ionosphere as a boundary condition at the upper boundary of the atmospheric conductor are analyzed. For the investigation of the electric field penetration from ground into the ionosphere it is sufficient to take into account only integral conductivity of the ionosphere. A mathematical simulation has shown that the resulting electric field in the ionosphere is negligible in contrast to the general point of view that such a penetration is a physical process which potentially creates ionospheric precursors of earthquakes. (C) 2013 Elsevier Ltd. All rights reserved.

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

Доп.точки доступа:
Denisenko, V.V.; Денисенко, Валерий Васильевич; Ampferer, M.; Pomozov, E.V.; Помозов, Егор Владимирович; Kitaev, A.V.; Китаев, Анатолий Валерьевич; Hausleitner, W.; Stangl, G.; Biernat, H.K.; Russian Foundation for Basic Research [09-06-91000, 12-05-00152]; Austrian "Fonds zur Forderung der wissenschaftlichen Forschung" [I193-N16]; "Verwaltungsstelle fur Auslandsbeziehungen" of the Austrian Academy of Sciences

    The solution of the Rankine-Hugoniot equations for fast shocks in an anisotropic kappa distributed medium
[Text] / D. F. Vogl [et al.] // Planet Space Sci. - 2003. - Vol. 51, Is. 12. - P715-722, DOI 10.1016/S0032-0633(03)00108-9. - Cited References: 28 . - ISSN 0032-0633
РУБ Astronomy & Astrophysics

Аннотация: In this paper, we concentrate on the analysis of the anisotropic Rankine-Hugoniot equations for perpendicular and oblique fast shocks. In particular, as additional information to the anisotropic set of equations, the threshold conditions of the fire-hose and mirror instability are used to bound the range of the pressure anisotropy downstream of the discontinuity. These anisotropic threshold conditions of the plasma instabilities are obtained via a kinetic approach using a generalized Lorentzian distribution function, the so-called kappa distribution function. Depending on up-stream conditions, these instabilities further define stable and unstable regions with regard to the pressure anisotropy downstream of the shock. The calculations are done for different upstream Alfven Mach numbers. We found that low values of the parameter kappa reduce the pressure anisotropy downstream of the shock. (C) 2003 Elsevier Ltd. All rights reserved.


Доп.точки доступа:
Vogl, D.F.; Langmayr, D.; Erkaev, N.V.; Еркаев, Николай Васильевич; Biernat, H.K.; Farrugia, C.J.; Muhlbachler, S.

    The effect of nanoparticle diffusion and thermophoresis on convective heat transfer of nanofluid in a circular tube
[Text] / I. I. Ryzhkov, A. V. Minakov // Int. J. Heat Mass Transf. - 2014. - Vol. 77. - P956-969, DOI 10.1016/j.ijheatmasstransfer.2014.05.045. - Cited References: 44. - This work is supported the Krasnoyarsk Regional Foundation of Scientific and Technical Activity (Grant No. 02/13) and the Russian President Grant No. MK-6296.2013.8. . - ISSN 0017-9310. - ISSN 1879-2189
РУБ Thermodynamics + Engineering, Mechanical + Mechanics

Аннотация: Laminar convective heat transfer of water-alumina nanofluid in a circular tube with uniform heat flux is investigated numerically on the basis of two-component model, which takes into account nanoparticle transport by diffusion and thermophoresis. A new expression for thermophoretic mobility is suggested on the basis of existing experimental results and theoretical concepts. It is shown that thermophoresis leads to a significant reduction of nanoparticle volume fraction in the boundary layer near the wall. The corresponding viscosity reduction causes the velocity increase near the wall and flattening of velocity profile near the tube axis to keep the mass flow rate constant. The decrease of wall shear stress leads to the decrease of the required pressure drop. The calculations for two-component model provide higher values of the local and average heat transfer coefficients in comparison with the one-component model. The difference does not exceed 10% and decreases with increasing the thermal Peclet number. The calculations for one-component model show the independence of local and average Nusselt numbers on the nanoparticle volume fraction. The results for two-component model predict the increase of Nusselt number when the thermophoretic effect becomes stronger. The effectiveness of water-alumina nanofluid is analyzed by plotting the average heat transfer coefficient against the required pumping power. It is shown that the nanofluid shows better performance than the base fluid in the range of low pumping power and, correspondingly, low inlet velocity. (C) 2014 Elsevier Ltd. All rights reserved.

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Держатели документа:
[Ryzhkov, Ilya I.] SB RAS, Inst Computat Modelling, Krasnoyarsk 660036, Russia
[Minakov, Andrey V.] Siberian Fed Univ, Inst Engn Phys & Radio Elect, Krasnoyarsk 660041, Russia
ИВМ СО РАН

Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Minakov, A.V.; Минаков, Андрей Викторович; Krasnoyarsk Regional Foundation of Scientific and Technical Activity [02/13]; Russian President Grant [MK-6296.2013.8]

    The influence of nanoparticle migration on forced convective heat transfer of nanofluid under heating and cooling regimes
[Text] / S. V. Kozlova, I. I. Ryzhkov // Eur. Phys. J. E. - 2014. - Vol. 37, Is. 9. - Ст. 87, DOI 10.1140/epje/i2014-14087-0. - Cited References: 44. - The authors are grateful to Dr. A. V. Minakov for assistance in ANSYS Fluent numerical calculations. This work is supported the Krasnoyarsk Regional Foundation of Scientific and Technical Activity (Grant 02/13). . - ISSN 1292-8941. - ISSN 1292-895X
РУБ Chemistry, Physical + Materials Science, Multidisciplinary + Physics, Applied + Polymer Science

Аннотация: In this paper, laminar convective heat transfer of water-alumina nanofluid in a circular tube with uniform heat flux at the tube wall is investigated. The investigation is performed numerically on the basis of two-component model, which takes into account nanoparticle transport by diffusion and thermophoresis. Two thermal regimes at the tube wall, heating and cooling, are considered and the influence of nanoparticle migration on the heat transfer is analyzed comparatively. The intensity of thermophoresis is characterized by a new empirical model for thermophoretic mobility. It is shown that the nanoparticle volume fraction decreases (increases) in the boundary layer near the wall under heating (cooling) due to thermophoresis. The corresponding variations of nanofluid properties and flow characteristics are presented and discussed. The intensity of heat transfer for the model with thermophoresis in comparison to the model without thermophoresis is studied by plotting the dependence of the heat transfer coefficient on the Peclet number. The effectiveness of water-alumina nanofluid is analyzed by plotting the average heat transfer coefficient against the required pumping power. The analysis of the results reveals that the water-alumina nanofluid shows better performance in the heating regime than in the cooling regime due to thermophoretic effect.

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Держатели документа:
[Kozlova, Sofya V.
Ryzhkov, Ilya I.] Inst Computat Modelling SB RAS, Krasnoyarsk 660036, Russia
ИВМ СО РАН

Доп.точки доступа:
Kozlova, S.V.; Ryzhkov, I.I.; Рыжков, Илья Игоревич; Krasnoyarsk Regional Foundation of Scientific and Technical Activity [02/13]

    Analysis of Fan Waves in a Laboratory Model Simulating the Propagation of Shear Ruptures in Rocks
/ B. G. Tarasov, V. M. Sadovskii, O. V. Sadovskaya // J. Appl. Mech. Tech. Phys. - 2017. - Vol. 58, Is. 7. - P1139-1152, DOI 10.1134/S0021894417070100. - Cited References:23. - This research was partially supported by the Centre for Offshore Foundation Systems (the University of Western Australia) and the Complex Fundamental Research Program no. II.2P "Integration and Development" of Siberian Branch of the Russian Academy of Sciences (grant no. 0356-2016-0728). . - ISSN 0021-8944. - ISSN 1573-8620
РУБ Mechanics + Physics, Applied

Аннотация: The fan-shaped mechanism of rotational motion transmission in a system of elastically bonded slabs on flat surface, simulating the propagation of shear ruptures in super brittle rocks, is analyzed. Such ruptures appear in the Earth's crust at seismogenic depths. They propagate due to the nucleation of oblique tensile microcracks, leading to the formation of a fan domino-structure in the rupture head. A laboratory physical model was created which demonstrates the process of fan-structure wave propagation. Equations of the dynamics of rotational motion of slabs as a mechanical system with a finite number of degrees of freedom are obtained. Based on the Merson method of solving the Cauchy problem for systems of ordinary differential equations, the computational algorithm taking into account contact interaction of slabs is developed. Within the framework of a simplified mathematical model of dynamic behavior of a fan-shaped system in the approximation of a continuous medium, the approximate estimates of the length of a fan depending on the velocity of its motion are obtained. It is shown that in the absence of friction a fan can move with any velocity that does not exceed the critical value, which depends on the size, the moment of inertia of slabs, the initial angle and the elasticity coefficient of bonds. In the presence of friction a fan stops. On the basis of discrete and continuous models, the main qualitative features of the behavior of a fan-structure moving under the action of applied tangential forces, whose values in a laboratory physical model are regulated by a change in the inclination angle of the rupture plane, are analyzed. Comparison of computations and laboratory measurements and observations shows good correspondence between the results.

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Держатели документа:
Univ Western Australia, Ctr Offshore Fdn Syst, Perth, WA 6009, Australia.
Inst Computat Modeling SB RAS, Krasnoyarsk 660036, Russia.

Доп.точки доступа:
Tarasov, B. G.; Sadovskii, V. M.; Sadovskaya, O. V.; Centre for Offshore Foundation Systems (the University of Western Australia); Complex Fundamental Research Program [II.2P, 0356-2016-0728]