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/ V.V. Kuznetsov, V.K. Andreev // Thermophys. Aeromechanics. - 2013. - Vol. 20, Is. 1. - P17-28. - Cited References: 7. - The work was financially supported by the Russian Foundation for Basic Research (Grant No. 10-01-00007), Federal Target Program "Scientific and Scientific-Pedagogical Personnel of Innovative Russia" (State Contract 14.740.11.0355) and Program of Fundamental Research of OEM RAS No. 2.13.2. . - 12. - ISSN 0869-8643РУБ Thermodynamics + Mechanics

Аннотация: The problem of stabilized combined motion of the gas flow and liquid film in a microchannel under the action of local heating with consideration of evaporation processes was set in selected variables. The exact solutions to the linearized problem were derived. The analytical formulas for calculation of the film thickness stabilized below the heater and the total rate of liquid evaporation were obtained. The technique of approximate calculation of total heat transfer is shown. Exemplary calculations are presented.

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Kuznetsov, V.V.; Andreev, V.K.; Андреев, Виктор Константинович

[Text] / A. P. Gavrilyuk, N. Y. Shaparev // Quantum Electron. - 2013. - Vol. 43, Is. 10. - P943-948, DOI 10.1070/QE2013v043n10ABEH015141. - Cited References: 18 . - ISSN 1063-7818РУБ Engineering, Electrical & Electronic + Physics, Applied

Аннотация: By means of numerical modelling of the combined effect of laser (1.06 mu m) and microwave (10(10)-10(13) s(-1)) radiation on the aluminium surface in vacuum it is shown that the additional action of microwave radiation with the frequency 10(12) s(-1) provides complete ionisation of the metal vapour (for the values of laser radiation duration and intensity used in the calculations), while in the absence of microwave radiation the vapour remains weakly ionised. The mathematical model used accounts for the processes, occurring in the condensed phase (heat conduction, melting), the evaporation and the kinetic processes in the resulting vapour.


Доп.точки доступа:
Shaparev, N.Ya.; Шапарев, Николай Якимович; Гаврилюк, Анатолий Петрович

[Text] / T. Penza [et al.] // Planet Space Sci. - 2008. - Vol. 56, Is. 9. - P1260-1272, DOI 10.1016/j.pss.2008.04.005. - Cited References: 53 . - ISSN 0032-0633РУБ Astronomy & Astrophysics

Аннотация: We investigate the efficiency of the atmospheric mass loss due to hydrodynamic blow-off over the lifetime of the exoplanet HD209458b by studying numerically its hydrogen wind for host star X-ray and EUV (XUV) fluxes between 1 and 100 times that of the present Sun. We apply a time-dependent numerical algorithm which is able to solve the system of hydrodynamic equations straight through the transonic point of the flow including Roche lobe effects. The mass loss rates are calculated as functions of the absorbed energy in the thermosphere. Depending on the heating efficiency for a hydrogen-rich thermosphere the maximum temperature obtained in our study at 1.5R(p1) by neglecting IR cooling is about 5000-10,000 K for heating efficiencies of 10% and 60%, respectively. We find that the upper atmosphere of HD209458b experiences hydrodynamic blow-off even at such low temperatures if one does not neglect gravitational effects caused by the proximity of the planet to its Roche lobe boundary. Depending on the heating efficiency, we find from the solution of the hydrodynamic equations of mass, momentum, and energy balance that energy-limited mass loss rate estimations overestimate the realistic mass loss rate at present time for HD209458b by several times. Using the maximum heating efficiency for hydrogen-rich atmospheres of 60% we find that HD209458b may experience an atmospheric mass loss rate at present time of about 3.5 x 10(10) g s(-1). The mass loss rate evolves to higher values for higher XUV fluxes expected during the early period of the planet's host star evolution, reaching values of several times 10(12) gs(-1). The integrated mass loss is found to be between 1.8% and 4.4% of the present mass of HD209458b. We found that the influence of the stellar tidal forces on atmospheric loss (the Roche lobe effect) is not significant at 0.045 AU. For a similar exoplanet, but at closer orbital distances <= 0.02 AU, the combined effect of the Roche lobe and the high XUV radiation result in much higher thermal loss rates of about 2.6 x 10(11) g s(-1) and even more for early stages. This leads to a total loss over 4 Gyr of 27.5% of the planetary mass. (c) 2008 Elsevier Ltd. All rights reserved.

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Доп.точки доступа:
Penza, T.; Erkaev, N.V.; Еркаев, Николай Васильевич; Kulikov, Y.N.; Langmayr, D.; Lammer, H.; Micela, G.; Cecchi-Pestellini, C.; Biernat, H.K.; Selsis, F.; Barge, P.; Deleuil, M.; Leger, A.

[Text] / N. V. Erkaev [et al.] // Astron. Astrophys. - 2007. - Vol. 472, Is. 1. - P329-334, DOI 10.1051/0004-6361:20066929. - Cited References: 26 . - ISSN 0004-6361РУБ Astronomy & Astrophysics

Аннотация: Context. A study of the mass loss enhancement for very close "Hot Jupiters" due to the gravitational field of the host star is presented. Aims. The influence of the proximity to a planet of the Roche lobe boundary on the critical temperature for blow-off conditions for estimating the increase of the mass loss rate through hydrodynamic blow-off for close-in exoplanets is investigated. Methods. We consider the gravitational potential for a star and a planet along the line that joins their mass centers and the energy balance equation for an evaporating planetary atmosphere including the effect of the stellar tidal force on atmospheric escape. Results. By studying the effect of the Roche lobe on the atmospheric loss from short-periodic gas giants we derived reasonably accurate approximate formulas to estimate atmospheric loss enhancement due to the action of tidal forces on a "Hot Jupiter" and to calculate the critical temperature for the onset of "geometrical blow-off", which are valid for any physical values of the Roche lobe radial distance. Using these formulas, we found that the stellar tidal forces can enhance the hydrodynamic evaporation rate from TreS-1 and OGLE-TR-56b by about 2 fold, while for HD 209458b we found an enhancement of about 50%. For similar exoplanets which are closer to their host star than OGLE-TR-56b, the mass loss enhancement can be even larger. Moreover, we showed that the effect of the Roche lobe allows "Hot Jupiters" to reach blow-off conditions at temperatures which are less than expected due to the stellar X-ray and EUV heating.


Доп.точки доступа:
Erkaev, N.V.; Еркаев, Николай Васильевич; Kulikov, Y.N.; Lammer, H.; Selsis, F.; Langmayr, D.; Jaritz, G.F.; Biernat, H.K.

[Text] / H. . Lammer [et al.] // Astron. Astrophys. - 2009. - Vol. 506, Is. 1. - P399-410, DOI 10.1051/0004-6361/200911922. - Cited References: 46. - The authors thank the anonymous referee for constructive comments and suggestions which helped to improve the paper. H. Lammer, P. Odert, M. Leitzinger, M. L. Khodachenko and A. Hanslmeier gratefully acknowledge the Austrian Fonds zur Forderung der wissenschaftlichen Forschung (FWF grant P19446) for supporting this project. M. Panchenko and M. L. Khodachenko acknowledge also the Austrian Fonds zur Forderung der wissenschaftlichen Forschung (project P20680-N16). H. Lammer, H. I. M. Lichtenegger, H. K. Biernat, Yu. N. Kulikov and N. V. Erkaev thank the AAS "Verwaltungsstelle fur Auslandsbeziehungen" and the RAS. H. Lammer, H. I. M. Lichtenegger, M. L. Khodachenko and Yu. N. Kulikov acknowledge support from the Helmholtz-Gemeinschaft as this research has been supported by the Helmholtz Association through the research alliance "Planetary Evolution and Life". H. Lammer, M. L. Khodachenko, T. Penz, and Yu. N. Kulikov also acknowledge the International Space Science Institute (ISSI; Bern, Switzerland) and the ISSI teams "Evolution of Habitable Planets" and "Evolution of Exoplanet Atmospheres and their Characterization". H. K. Biernat acknowledges additional support due to the Austrian Science Fund under project P20145-N16. The authors also acknowledge fruitful discussions during various meetings related to the Europlanet N2 activities as well as within the N2 Exoplanet discipline working group DWG 7. T. Penz and G. Micela acknowledge support by the Marie Curie Fellowship Contract No. MTKD-CT-2004-002769 of the project "The influence of stellar high radiation on planetary atmospheres". The authors also thank the Austrian Ministry bm:bwk and ASA for funding the CoRoT project. . - ISSN 0004-6361РУБ Astronomy & Astrophysics

Аннотация: Aims. We study the possible atmospheric mass loss from 57 known transiting exoplanets around F, G, K, and M-type stars over evolutionary timescales. For stellar wind induced mass loss studies, we estimate the position of the pressure balance boundary between Coronal Mass Ejection (CME) and stellar wind ram pressures and the planetary ionosphere pressure for non- or weakly magnetized gas giants at close orbits. Methods. The thermal mass loss of atomic hydrogen is calculated by a mass loss equation where we consider a realistic heating efficiency, a radius-scaling law and a mass loss enhancement factor due to stellar tidal forces. The model takes into account the temporal evolution of the stellar EUV flux by applying power laws for F, G, K, and M-type stars. The planetary ionopause obstacle, which is an important factor for ion pick-up escape from non- or weakly magnetized gas giants is estimated by applying empirical power-laws. Results. By assuming a realistic heating efficiency of about 10-25% we found that WASP-12b may have lost about 6-12% of its mass during its lifetime. A few transiting low density gas giants at similar orbital location, like WASP-13b, WASP-15b, CoRoT-1b or CoRoT-5b may have lost up to 1-4% of their initial mass. All other transiting exoplanets in our sample experience negligible thermal loss (<= 1%) during their lifetime. We found that the ionospheric pressure can balance the impinging dense stellar wind and average CME plasma flows at distances which are above the visual radius of "Hot Jupiters", resulting in mass losses <2% over evolutionary timescales. The ram pressure of fast CMEs cannot be balanced by the ionospheric plasma pressure for orbital distances between 0.02-0.1 AU. Therefore, collisions of fast CMEs with hot gas giants should result in large atmospheric losses which may influence the mass evolution of gas giants with masses
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Доп.точки доступа:
Lammer, H.; Odert, P.; Leitzinger, M.; Khodachenko, M.L.; Panchenko, M.; Kulikov, Y.N.; Zhang, T.L.; Lichtenegger, H.I.M.; Erkaev, N.V.; Еркаев, Николай Васильевич; Wuchterl, G.; Micela, G.; Penz, T.; Biernat, H.K.; Weingrill, J.; Steller, M.; Ottacher, H.; Hasiba, J.; Hanslmeier, A.; Austrian Fonds zur Forderung der wissenschaftlichen Forschung [P19446, P20680-N16]; Helmholtz Association; Austrian Science Fund [P20145-N16]; "The influence of stellar high radiation on planetary atmospheres" [MTKD-CT-2004-002769]

/ C. P. Johnstone [et al.] // Astrophys. J. Lett. - 2015. - Vol. 815, Is. 1, DOI 10.1088/2041-8205/815/1/L12 . - ISSN 2041-8205
Аннотация: Terrestrial planets formed within gaseous protoplanetary disks can accumulate significant hydrogen envelopes. The evolution of such an atmosphere due to XUV driven evaporation depends on the activity evolution of the host star, which itself depends sensitively on its rotational evolution, and therefore on its initial rotation rate. In this Letter, we derive an easily applicable method for calculating planetary atmosphere evaporation that combines models for a hydrostatic lower atmosphere and a hydrodynamic upper atmosphere. We show that the initial rotation rate of the central star is of critical importance for the evolution of planetary atmospheres and can determine if a planet keeps or loses its primordial hydrogen envelope. Our results highlight the need for a detailed treatment of stellar activity evolution when studying the evolution of planetary atmospheres. © 2015. The American Astronomical Society. All rights reserved.

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Держатели документа:
University of Vienna, Department of Astrophysics, Vienna, Austria
Space Research Institute, Austrian Academy of Sciences, Graz, Austria
Institute for Computational Modelling, Siberian Division, Russian Academy of Sciences, Krasnoyarsk, Russian Federation
Siberian Federal University, Krasnoyarsk, Russian Federation

Доп.точки доступа:
Johnstone, C. P.; Gudel, M.; Stokl, A. ; Lammer, H.; Tu, L.; Kislyakova, K. G.; Luftinger, T.; Odert, P.; Erkaev, N.V.; Еркаев, Николай Васильевич; Dorfi, E. A.
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/ V. B. Bekezhanova, O. N. Goncharova // Fluid Dyn. Res. - 2016. - Vol. 48, Is. 6, DOI 10.1088/0169-5983/48/6/061408 . - ISSN 0169-5983
Аннотация: A new exact solution of the equations of free convection has been constructed in the framework of the Oberbeck-Boussinesq approximation of the Navier-Stokes equations. The solution describes the joint flow of an evaporating viscous heat-conducting liquid and gas-vapor mixture in a horizontal channel. In the gas phase the Dufour and Soret effects are taken into account. The consideration of the exact solution allows one to describe different classes of flows depending on the values of the problem parameters and boundary conditions for the vapor concentration. A classification of solutions and results of the solution analysis are presented. The effects of the external disturbing influences (of the liquid flow rates and longitudinal gradients of temperature on the channel walls) on the stability characteristics have been numerically studied for the system HFE7100-nitrogen in the common case, when the longitudinal temperature gradients on the boundaries of the channel are not equal. In the system both monotonic and oscillatory modes can be formed, which damp or grow depending on the values of the initial perturbations, flow rates and temperature gradients. Hydrodynamic perturbations are most dangerous under large gas flow rates. The increasing oscillatory perturbations are developed due to the thermocapillary effect under large longitudinal gradients of temperature. The typical forms of the disturbances are shown. © 2016 The Japan Society of Fluid Mechanics and IOP Publishing Ltd.

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Держатели документа:
Institute of Computational Modelling SB RAS, 50/44 Krasnoyarsk, Akademgorodok, Russian Federation
Institute of Mathematics and Computer Science, Siberian Federal University, Svobodny 79, Krasnoyarsk, Russian Federation
Altai State University, Lenina 61, Barnaul, Russian Federation
Institute of Thermophysics, SB RAS, Lavrentyev 1, Novosibirsk, Russian Federation

Доп.точки доступа:
Bekezhanova, V. B.; Goncharova, O. N.

[Text] : abstract / V.B. Bekezhanova, I.A. Shefer // Abstarcts of Russian-French Workshop «Mathematical Hydrodynamics». - Novosibirsk : Novosibirsk state university, 2016. - P12-13


Доп.точки доступа:
Shefer, I. A.; Шефер И.А.; Бекежанова, Виктория Бахытовна

[Text] : abstract / V. B. Bekezhanova, O. N. Goncharova // Book of Abstracts International Symposium and School for Young Scientists «Interfacial Phenomena and Heat Transfer». - Novosibirsk : Kutateladze Institute of thermophysics SB RAS, 2016. - P83


Доп.точки доступа:
Goncharova, O.N.; Бекежанова, Виктория Бахытовна

[Text] : abstract / V. B. Bekezhanova, O. N. Goncharova // Abstracts of IMA8 - 8th Conference of the International Marangoni Association. - 2016. - P42

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Goncharova, O.N.; Бекежанова, Виктория Бахытовна

[Text] : abstract / V. B. Bekezhanova, O. N. Goncharova // Abstracts of 11th International Conference on Two-Phase Systems For Ground and Space Applications. - Marseilles, 2016. - P65-66


Доп.точки доступа:
Goncharova, O.N.; Бекежанова, Виктория Бахытовна

/ V. B. Bekezhanova [et al.] // Fluid Dyn. - 2017. - Vol. 52, Is. 2. - P189-200, DOI 10.1134/S001546281702003X. - Cited References:23. - The work received financial support from RFBR (No. 14-08-00163). . - ISSN 0015-4628. - ISSN 1573-8507РУБ Mechanics + Physics, Fluids & Plasmas

Аннотация: The problem of stability of two-layer (fluid-gas) flows with account of evaporation at the thermocapillary interface is studied under the condition of a fixed gas flow rate. In the upper gas-vapor layer, the Dufour effect is taken into account. A novel exact solution of the Navier-Stokes equations in the Boussinesq approximation is constructed. The effects of longitudinal temperature gradients, gravity, thicknesses of the gas and fluid layers, and the gas flow rate on the flow structure, the onset of recirculated flows near the interface, the evaporation rate, and the properties of characteristic disturbances are investigated.

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Держатели документа:
Russian Acad Sci, Siberian Branch, Inst Computat Modelling, Akademgorodok 50,Str 44, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Inst Math & Fundamental Informat, Pr Svobodnyi 79, Krasnoyarsk 660041, Russia.
Russian Acad Sci, Siberian Branch, Kutateladze Inst Thermophys, Pr Akad Lavrenteva 1, Novosibirsk 630090, Russia.
Altai State Univ, Pr Lenina 61a, Barnaul 656049, Russia.

Доп.точки доступа:
Goncharova, O. N.; Rezanova, E. B.; Shefer, I. A.; Бекежанова, Виктория Бахытовна; RFBR [14-08-00163]

/ V. B. Bekezhanova, O. N. Goncharova // J. Phys. Conf. Ser. - 2017. - Vol. 894, Is. 1, DOI 10.1088/1742-6596/894/1/012023 . - ISSN 1742-6588
Аннотация: A three-dimensional problem of evaporative convection in a system of the immiscible media with a common thermocapillary interface is studied. New exact solution, which is a generalization of the Ostroumov - Birikh solution of the Navier - Stokes equations in the Oberbeck - Boussinesq approximation, is presented in order to describe the joint flows of the liquid and gas - vapor mixture in an infinite channel with a rectangular cross-section. The motion occurs in the bulk force field under action of a constant longitudinal temperature gradient. The velocity components depend only on the transverse coordinates. The functions of pressure, temperature and concentration of vapor in the gas are characterized by the linear dependence on the longitudinal coordinate. In the framework of the problem statement, which takes into account diffusive mass flux through the interface and zero vapor flux at the upper boundary of the channel, the influence of the gravity and intensity of the thermal action on flow structure is studied. The original three-dimensional problem is reduced to a chain of two-dimensional problems which are solved numerically with help of modification of the method of alternating directions. Arising flows can be characterized as a translational-rotational motion, under that the symmetrical double, quadruple or sextuple vortex structures are formed. Quantity, shape and structure of the vortexes also depend on properties of the working media.

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Держатели документа:
Institute of Computational Modeling SB RAS, Krasnoyarsk, Russian Federation
Institute of Thermophysics SB RAS, Novosibirsk, Russian Federation
Altai State University, Barnaul, Russian Federation

Доп.точки доступа:
Bekezhanova, V. B.; Goncharova, O. N.

/ V. B. Bekezhanova, O. N. Goncharova // J. Phys. Conf. Ser. - 2017. - Vol. 899, Is. 3, DOI 10.1088/1742-6596/899/3/032006 . - ISSN 1742-6588
Аннотация: The solution of special type of the Boussinesq approximation of the Navier - Stokes equations is used to simulate the two-layer evaporative fluid flows. This solution is the 3D generalization of the Ostroumov - Birikh solution of the equations of free convection. Modeling of the 3D fluid flows is performed in an infinite channel of the rectangular cross section without assumption of the axis-symmetrical character of the flows. Influence of gravity and evaporation on the dynamic and thermal phenomena in the system is studied. The fluid flow patterns are determined by various thermal, mechanical and structural effects. Numerical investigations are performed for the liquid - gas system like ethanol - nitrogen and HFE-7100 - nitrogen under conditions of normal and low gravity. The solution allows one to describe a formation of the thermocapillary rolls and multi-vortex structures in the system. Alteration of topology and character of the flows takes place with change of the intensity of the applied thermal load, thermophysical properties of working media and gravity action. Flows with translational, translational-rotational or partially reverse motion can be formed in the system. © Published under licence by IOP Publishing Ltd.

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Держатели документа:
Institute of Computational Modeling SB RAS, Academgorodok 50/44, Krasnoyarsk, Russian Federation
Institute of Thermophysics SB RAS, Ac. Lavrentieva ave 1, Novosibirsk, Russian Federation
Altai State University, pr Lenina 61, Barnaul, Russian Federation

Доп.точки доступа:
Bekezhanova, V. B.; Goncharova, O. N.

: статья / Victoria B. Bekezhanova, Olga N. Goncharova, Ilia A. Shefer // Журнал Сибирского федерального университета. Серия: Математика и физика. - 2018. - Т. 11, № 3. - P342-355, DOI 10.17516/1997-1397-2018-11-3-342-355 . - ISSN 1997-1397
   Перевод заглавия: Анализ точного решения задачи испарительной конвекции (обзор). Часть II. Трехмерные течения

УДК

512.54

Аннотация: In thepaper thereviewof exact solutionsof the three-dimensional convectionproblemsispresented. The solutions allow one to model the two-layer convective fluid flows with evaporation at the thermocapillary interface.
В настоящейработе представлен обзор точных решений трехмерных задач конвекции для моделирования двухслойных конвективных течений с испарением на термокапиллярной границе раздела.

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Держатели документа:
Altai State University
Institute of Computational Modeling SB RAS
Institute of Mathematics and Computer Science Siberian Federal University
Institute of Thermophysics SB RAS

Доп.точки доступа:
Bekezhanova, Victoria B.; Бекежанова Виктория Б.; Goncharova, Olga N.; Гончарова Ольга Н.; Shefer, Ilia A.; Шефер Илья А.

/ V. B. Bekezhanova, O. N. Goncharova // Appl. Math. Model. - 2018. - Vol. 62. - P145-162, DOI 10.1016/j.apm.2018.05.021 . - ISSN 0307-904X
Аннотация: Theoretical and numerical study of the convection processes, which are accompanied by evaporation/condensation, in the framework of new non-standard problem is largely motivated by new physical experiments. One of the principal questions is to understand the character and to evaluate the degree of influence of particular factors or their combined action on the structure of the joint flows of liquid and gas-vapor mixture. The flow topology is determined by four main mechanisms: natural and thermocapillary convection, tangential stresses and mass transfer due to evaporation at the interface. The mathematical modeling of the fluid flows in an infinite channel with a rectangular cross section is carried out on the basis of the solution of a special type of the convection equations. The effects of thermodiffusion and diffusive thermal conductivity in the gas phase and evaporation at the thermocapillary interface are taken into consideration. Numerical investigations are performed for the liquid – gas (ethanol – nitrogen) system under normal and low gravity. The fluid flows are characterized as translational and progressively rotational motions and can be realized in various forms. © 2018 Elsevier Inc.

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Держатели документа:
Institute of Computational Modeling SB RAS, Akademgorodok 50/44, Krasnoyarsk, Russian Federation
Institute of Thermophysics SB RAS, Ac. Lavrentieva ave 1, Novosibirsk, Russian Federation
Altai State University, pr Lenina 61, Barnaul, Russian Federation

Доп.точки доступа:
Bekezhanova, V. B.; Goncharova, O. N.

: статья / Victoria B. Bekezhanova, Olga N. Goncharova, Ilia A. Shefer // Журнал Сибирского федерального университета. Серия "Математика и физика". - 2018. - Т. 11, № 2. - P178-190, DOI 10.17516/1997-1397-2018-11-2-178-190 . - ISSN 1997-1397
   Перевод заглавия: Анализ точного решения задачи испарительной конвекции (обзор). Часть I. Плоский случай

УДК

512.54

Аннотация: Development of theory describing the convection under conditions of "liquid - gas" phase transition, is caused by the active experimental study of the convective phenomena accompanied by evaporation/condensation at interphase. Results of the analytical and numerical investigation of new nonstandardproblems of heat and mass transfer in domains with free surfaces or interfaces allow one to evaluate the adequacy of new mathematical models and to derive new characteristic criteria. The obtained fundamental knowledge on physical mechanisms of the studied processes provides thebasis of modification and improvement of the fluidic technologies using the evaporating liquids and gas-vapor mixtures as working media.Inthepaperthe analysisofthe exact solutionoftheconvectionequations, whichgivesapossibility to model the two-layer convective fluid flows with evaporation, is presented.
Развитие теории, описывающей конвекциювусловияхфазового перехода "жидкость-газ",во многомвызвано активным экспериментальным изучениемконвективных явлений, сопровождающихся испарением/конденсацией на межфазных границах.Результаты аналитическогоичисленного исследования новых нестандартных задач тепло-имассопереносавобластях со свободными границами или поверхностями раздела позволяют оценить адекватность новых математических моделей и вывести новые определяющие критерии. Полученные фундаментальные знания о физических механизмах изучаемых процессовслужат основой модификациии совершенствования жидкостных технологий, использующих в качестве рабочих сред испаряющиеся жидкости и парогазовые смеси. В настоящей работе представлен анализ точного решения уравнений конвекции, позволяющего моделировать двухслойные конвективные течения с испарением.

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Держатели документа:
Altai State University
Institute of Mathematics and Computer Science Siberian Federal University
Institute of Mathematics and Computer Science SiberianFederal University
Institute of Thermophysics SB RAS
nstitute of Computational Modeling SB RAS

Доп.точки доступа:
Bekezhanova, Victoria B.; Бекежанова Виктория Б.; Goncharova, Olga N.; Гончарова Ольга Н.; Shefer, Ilia A.; Шефер Илья А.

[Текст] : статья / Виктория Бахытовна Бекежанова, Ольга Николаевна Гончарова // Известия Алтайского государственного университета. - 2018. - № 4. - С. 56-61, DOI 10.14258/izvasu(2018)4-10 . - ISSN 1561-9443
   Перевод заглавия: Characteristics of a Two-Layer Flow with Evaporation in a Plane Channel Subjected to Heating from the Bottom

УДК

517.9

Аннотация: Исследуются особенности конвективных режимов, возникающих в двухслойной системе в условиях фазового перехода. Математическая модель для описания испарительной конвекции в бесконечном горизонтальном канале основана на аппроксимации Обербека - Буссинеска уравнений Навье - Стокса и соотношениях на термокапиллярной границе раздела. Точное решение определяющих уравнений - аналог решения Остроумова - Бириха - имеет групповую природу и позволяет учесть одновременное наличие горизонтального и вертикального градиентов температуры и влияние термодиффузионных эффектов (прямого и обратного) в парогазовой смеси и на межфазной границе. Описаны тепловая и топологическая структуры совместных течений испаряющейся жидкости и смеси ее паров с инертным газом, изучены характеристики паросодержания в верхнем слое. В работе приведены новые результаты по исследованию устойчивости изучаемого точного решения уравнений конвекции. Представлены типичные формы возникающих характеристических возмущений в условиях равных продольных температурных градиентов на внешних стенках канала и ненулевого поперечного перепада температуры. Описаны определяющие механизмы, отвечающие за формирование каждого типа структур.
Features of convective regimes arising in a twolayer system with a phase transition are investigated. A mathematical model to describe the evaporative convection in an infinite horizontal channel is based on the Oberbeck - Boussinesq approximation of the Navier - Stokes equations and on the relations on the thermocapillary interface. An exact solution of the governing equations is the Ostroumov - Birikh solution analog. It has a group origination and allows one to take into account simultaneous presence of horizontal and vertical temperature gradients and influence of thermodiffusion effects (direct and inverse) both in the gas-vapor mixture and on the interface. Thermal and topological patterns of the joint flows of an evaporating liquid and a mixture of its vapor with an inert gas are described. Characteristics of vapor quality in the upper layer are studied. New results on stability of the exact solution under given consideration are presented in the paper. Typical forms of arising characteristic perturbations are calculated for the case of equal longitudinal temperature gradients on the external channel walls and of nonzero transversal temperature drop. Governing mechanisms responsible for the formation of each type of the structures are described.

РИНЦ

Держатели документа:
Алтайский государственный университет
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Бекежанова, Виктория Бахытовна; Bekezhanova V.B.; Гончарова, Ольга Николаевна; Goncharova O.N.

/ D. Kubyshkina [et al.] // Astrophys. J. Lett. - 2018. - Vol. 866, Is. 2. - Ст. L18, DOI 10.3847/2041-8213/aae586. - Cited References:23. - We acknowledge the FFG project P853993, the FWF/NFN projects S11607-N16, S11604-N16, and the FWF projects P27256-N27 and P30949-N36. N.V.E. acknowledges support by RFBR grant No. 18-05-00195-a and 16-52-14006 ANF_a. We thank the anonymous referee for useful comments. . - ISSN 2041-8205. - ISSN 2041-8213РУБ Astronomy & Astrophysics

Аннотация: Studies of planetary atmospheric composition, variability, and evolution require appropriate theoretical and numerical tools to estimate key atmospheric parameters, among which the mass-loss rate is often the most important. In evolutionary studies, it is common to use the energy-limited formula, which is attractive for its simplicity but ignores important physical effects and can be inaccurate in many cases. To overcome this problem, we consider a recently developed grid of about 7000 one-dimensional upper-atmosphere hydrodynamic models computed for a wide range of planets with hydrogen-dominated atmospheres from which we extract the mass-loss rates. The grid boundaries are [1:39] M-circle plus in planetary mass, [1:10] R-circle plus in planetary radius, [300:2000] K in equilibrium temperature, [0.4:1.3] M-circle dot in host star's mass, [0.002:1.3] au in orbital separation, and about [10(26):5x10(30)] erg s(-1) in stellar X-ray and extreme ultraviolet luminosity. We then derive an analytical expression for the atmospheric mass-loss rates based on a fit to the values obtained from the grid. The expression provides the mass-loss rates as a function of planetary mass, planetary radius, orbital separation, and incident stellar high-energy flux. We show that this expression is a significant improvement to the energy-limited approximation for a wide range of planets. The analytical expression presented here enables significantly more accurate planetary evolution computations without increasing computing time.

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Держатели документа:
Austrian Acad Sci, Space Res Inst, Schmiedlstr 6, A-8042 Graz, Austria.
Russian Acad Sci, Siberian Branch, Inst Computat Modelling, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
Univ Vienna, Inst Astron, Turkenschanzstr 17, A-1180 Vienna, Austria.
Karl Franzens Univ Graz, Inst Phys, IGAM, Univ Pl 5, A-8010 Graz, Austria.

Доп.точки доступа:
Kubyshkina, D.; Fossati, L.; Erkaev, N., V; Cubillos, P. E.; Johnstone, C. P.; Kislyakova, K. G.; Lammers, H.; Lendl, M.; Odert, P.; FFG project [P853993]; FWF/NFN projects [S11607-N16, S11604-N16]; FWF projects [P27256-N27, P30949-N36]; RFBR [18-05-00195-a, 16-52-14006 ANF_a]

[Текст] : доклад, тезисы доклада / В. Б. Бекежанова, О. Н. Гончарова // Пермские гидродинамические научные чтения : сборник материалов V Всероссийской конференции с международным участием, посвященной памяти профессоров Г. З. Гершуни, Е. М. Жуховицкого и Д. В. Любимова. - Пермь : Пермский государственный национальный исследовательский университет, 2018. - С. 45-47 . - ISBN 978-5-7944-3158-2
   Перевод заглавия: Structure and characteristic perturbations of the two-layer flows with evaporation in a horizontal channel

УДК

536.25

Аннотация: Изучаются особенности конвективных течений в двухслойной системе с испарением на термокапиллярной межфазной границе. Жидкость и газ заполняют плоский канал, находящийся под действием поперечно направленной силы тяжести и продольных градиентов температуры, поддерживаемых на границах. Математическая модель для описания испарительной конвекции включает уравнения Навье-Стокса в приближении Обербека-Буссинеска, соотношения на границе раздела и граничные условия на твердых стенках. Построено точное решение определяющей системы уравнений, являющееся решением типа Остроумова-Бириха, имеющее групповую природу и позволяющее учесть одновременное наличие горизонтального и вертикального градиентов температуры, эффекты диффузионной теплопроводности и термодиффузии пара в газовой среде и на межфазной границе. Проведена классификация течений, описываемых точным решением. Выделены следующие типы течений: чисто термокапиллярное, смешанное и течение пуазейлевской структуры. В случае отсутствия потока пара на верхней твердой стенке канала исследована линейная устойчивость всех классов течений. Представлены типичные формы возникающих характеристических возмущений в условиях равных продольных градиентов на внешних стенках канала и ненулевого поперечного перепада температуры. Описаны определяющие механизмы, отвечающие за формирование каждого типа структур.
Features of the convective flows with evaporation at a thermocapillary interface are studied. The fluids fill a plane channel being under action of the transversely directed gravity field and longitudinal temperature gradients on the channel boundaries. Mathematical model for description of the evaporative convection includes the Oberbeck - Boussinesq approximation of the Navier - Stokes equations and the relations on the thermocapillary interface and fixed walls. An exact solution of the governing equations is constructed. It is the Ostroumov - Birikh type of solutions of the convection equations, has the group nature and allows one to take into account simultaneous presence of the horizontal and vertical temperature gradients and the effects of the diffusive thermal conductivity and thermodiffusion of the vapor in a gas medium and on the interface. A classification of the flows described by the exact solution is carried out. The following flow classes are selected: the pure thermocapillary and mixed flows, and the Poiseuille type of flows. In the case of absence of vapor flux at the upper rigid wall the linear stability of all the flow classes is investigated. The typical forms of the arising characteristic perturbations are presented under conditions of equal longitudinal temperature gradients on the external channel walls and of the nonzero transversal temperature drop. Governing mechanisms responsible for formation of the structure types are described.

РИНЦ,
Источник статьи

Держатели документа:
Алтайский государственный университет
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Бекежанова, В.Б.; Bekezhanova V.B.; Гончарова, О.Н.; Goncharova O.N.; Пермские гидродинамические научные чтения(2018 ; 26.09 - 29.09 ; Пермь)
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