[Text] : статья / V.B. Bekezhanova // Journal of Applied Mechanics and Technical Physics. - 2011. - Vol. 52, Iss. 1. - p. 74-81DOI 10.1134/S0021894411010111
. -
Аннотация: An exact solution is obtained for the problem of steady flow in a system of two horizontal layers of immiscible fluids with a common interface. The stability of the flow is studied by a linearization method. It is shown that the occurrence of instabilities is due to the different governing parameters of the fluids (thickness, heating conditions, viscous and thermal conductivity of the fluids). It is found that under constant gravity conditions, the perturbations are monotonic, and in zero gravity, oscillatory thermocapillary instability occurs.
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Доп.точки доступа:
Бекежанова, Виктория Бахытовна
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Convective instability of Marangoni-Poiseuille flow under a longitudinal temperature gradient
Four-stage computational technology with adaptive numerical methods for computational aerodynamics
/ V.Shaydurov, T.Liu, Z.Zheng // AIP Conference Proceedings. - 2012. - Vol. 1487: 4th International Conference on Application of Mathematics in Technical and Natural Sciences: Memorial Volume devoted to Prof. Christo I. Christov, AMiTaNS 2012 (11 June 2012 through 16 June 2012, St. Constantine and Helena) . - pp. 42-48, DOI 10.1063/1.4758940
. -
Кл.слова (ненормированные):
four-stage computational technology -- heat-conducting gas -- high-order solvers -- Time-dependent Navier-Stokes equations
Аннотация: Computational aerodynamics is a key technology in aircraft design which is ahead of physical experiment and complements it. Of course all three components of computational modeling are actively developed: mathematical models of real aerodynamic processes, numerical algorithms, and high-performance computing. The most impressive progress has been made in the field of computing, though with a considerable complication of computer architecture. Numerical algorithms are developed more conservative. More precisely, they are offered and theoretically justified for more simple mathematical problems. Nevertheless, computational mathematics now has amassed a whole palette of numerical algorithms that can provide acceptable accuracy and interface between modern mathematical models in aerodynamics and high-performance computers. A significant step in this direction was the European Project ADIGMA whose positive experience will be used in International Project TRISTAM for further movement in the field of computational technologies for aerodynamics. This paper gives a general overview of objectives and approaches intended to use and a description of the recommended four-stage computer technology. В© 2012 American Institute of Physics.
Scopus,
РИНЦ
Доп.точки доступа:
Liu, T.; Zheng, Z.; Шайдуров, Владимир Викторович
Кл.слова (ненормированные):
four-stage computational technology -- heat-conducting gas -- high-order solvers -- Time-dependent Navier-Stokes equations
Аннотация: Computational aerodynamics is a key technology in aircraft design which is ahead of physical experiment and complements it. Of course all three components of computational modeling are actively developed: mathematical models of real aerodynamic processes, numerical algorithms, and high-performance computing. The most impressive progress has been made in the field of computing, though with a considerable complication of computer architecture. Numerical algorithms are developed more conservative. More precisely, they are offered and theoretically justified for more simple mathematical problems. Nevertheless, computational mathematics now has amassed a whole palette of numerical algorithms that can provide acceptable accuracy and interface between modern mathematical models in aerodynamics and high-performance computers. A significant step in this direction was the European Project ADIGMA whose positive experience will be used in International Project TRISTAM for further movement in the field of computational technologies for aerodynamics. This paper gives a general overview of objectives and approaches intended to use and a description of the recommended four-stage computer technology. В© 2012 American Institute of Physics.
Scopus,
РИНЦ
Доп.точки доступа:
Liu, T.; Zheng, Z.; Шайдуров, Владимир Викторович
Some generalizations based on stratification and vertical mixing in meromictic Lake Shira, Russia, in the period 2002-2009
[Text] / D.Y. Rogozin [et al.] // Aquat. Ecol. - 2010. - Vol. 44, Is. 3. - pp. 485-496, DOI 10.1007/s10452-010-9328-6. - Cited References: 27. - We thank Mr. Fyodor Kozlov for assistance in winter lake surveys, Dr. Alexander Tolomeev and Dr. Egor Zadereev (Institute of Biophysics SD RAS) for field data of August 2006, Dr. Galina Kalacheva (Institute of Biophysics SD RAS) for ash content determination and all others who helped us in expeditions. We are also very grateful to Dr. Wolf Mooij (Netherlands Institute of Ecology) and two anonymous reviewers for valuable comments and advice on article preparation. This work was partly supported by the Netherlands Organization for Scientific Research, Grant 047.011.2004.030, the Russian Foundation for Basic Research, Grants No. 09-04-01114-a and 09-05-00915-a, by Siberian Branch of Russian Academy of Sciences, Integrative Project No. 95 and joint Taiwan-Siberian Project No. 149, by Russian Academy of Sciences, Program No. 23.15, by award No. PG07-002-1 of the Ministry of Education and Sciences of Russian Federation and U.S. Civilian Research & Development Foundation for the Independent States of the Former Soviet Union (CRDF).
. - ISSN 1386-2588
РУБ Ecology + Limnology + Marine & Freshwater Biology
Аннотация: In a brackish, temperate, 24-m-deep Lake Shira, the profiles of salinity, temperature, oxygen and sulfide concentrations were measured on a seasonal basis from 2002 to 2009. The lake was shown to be meromictic with autumnal overturn restricted to mixolimnion. The depth of mixolimnion and position of oxic-anoxic interface varied annually. The spring mixing processes contribute to the formation of mixolimnion in autumn. The exceptionally windy spring of 2007 caused the deepening of mixolimnion in the winter of 2008. The winter position of oxic-anoxic interface was affected by the position of lower boundary of mixolimnion in all winters. The salinity in the winter mixolimnion increased compared with the autumn because of freezing out of salts from the upper water layers meters during ice formation and their dissolution in water below. The profiles of salinity and temperature were simulated by the mathematical 1-D model of temperature and salinity conditions taking into account ice formation. The simulated profiles generally coincided with the measured ones. The coincidence implies that simplified one-dimensional model can be applied to roughly describe salinity and density profiles and mixing behavior of Lake Shira.
Доп.точки доступа:
Rogozin, D.Y.; Genova, S.N.; Генова, Светлана Николаевна; Gulati, R.D.; Degermendzhy, A.G.
Рубрики:
PHOTOTROPHIC SULFUR BACTERIA
MONO LAKE
CHEMOCLINE
Кл.слова (ненормированные):
Meromixis -- Mixolimnion -- Oxic-anoxic interface -- Thermocline -- Weather conditions -- 1-D model
PHOTOTROPHIC SULFUR BACTERIA
MONO LAKE
CHEMOCLINE
Кл.слова (ненормированные):
Meromixis -- Mixolimnion -- Oxic-anoxic interface -- Thermocline -- Weather conditions -- 1-D model
Аннотация: In a brackish, temperate, 24-m-deep Lake Shira, the profiles of salinity, temperature, oxygen and sulfide concentrations were measured on a seasonal basis from 2002 to 2009. The lake was shown to be meromictic with autumnal overturn restricted to mixolimnion. The depth of mixolimnion and position of oxic-anoxic interface varied annually. The spring mixing processes contribute to the formation of mixolimnion in autumn. The exceptionally windy spring of 2007 caused the deepening of mixolimnion in the winter of 2008. The winter position of oxic-anoxic interface was affected by the position of lower boundary of mixolimnion in all winters. The salinity in the winter mixolimnion increased compared with the autumn because of freezing out of salts from the upper water layers meters during ice formation and their dissolution in water below. The profiles of salinity and temperature were simulated by the mathematical 1-D model of temperature and salinity conditions taking into account ice formation. The simulated profiles generally coincided with the measured ones. The coincidence implies that simplified one-dimensional model can be applied to roughly describe salinity and density profiles and mixing behavior of Lake Shira.
Доп.точки доступа:
Rogozin, D.Y.; Genova, S.N.; Генова, Светлана Николаевна; Gulati, R.D.; Degermendzhy, A.G.
Joint unidirectional motion of two viscous heat-conducting fluids in a tube
[Text] / V.K. Andreev // J. Appl. Mech. Tech. Phys. - 2010. - Vol. 51, Is. 4. - pp. 497-509, DOI 10.1007/s10808-010-0066-2. - Cited References: 6. - This work was supported by the Russian Foundation for Basic Research (Grant No. 08-01-00762) and Interdisciplinary Integration Project of the Siberian Division of the Russian Academy of Science No. 65.
. - ISSN 0021-8944
РУБ Mechanics + Physics, Applied
Аннотация: This paper studies an invariant solution of the problem of joint motion of two heat-conducting viscous immiscible fluids which have a common interface in a cylindrical tube under an unsteady pressure gradient. The problem reduces to a coupled initial-boundary-value problem for parabolic equations. A priori estimates of velocity and temperature perturbations are obtained. The steady state of the system is determined, and it is proved that if, in one of the fluids, the pressure gradient rapidly approaches zero, the perturbations of all quantities tend to zero. It is shown that if the pressure gradient has a nonzero limit, the solution reaches a steady state. In this case, the velocity field in the limit is the same as in conjugate Poiseuille flow, and the temperature is represented as a polynomial of the fourth order on the radial coordinate.
Доп.точки доступа:
Андреев, Виктор Константинович
Аннотация: This paper studies an invariant solution of the problem of joint motion of two heat-conducting viscous immiscible fluids which have a common interface in a cylindrical tube under an unsteady pressure gradient. The problem reduces to a coupled initial-boundary-value problem for parabolic equations. A priori estimates of velocity and temperature perturbations are obtained. The steady state of the system is determined, and it is proved that if, in one of the fluids, the pressure gradient rapidly approaches zero, the perturbations of all quantities tend to zero. It is shown that if the pressure gradient has a nonzero limit, the solution reaches a steady state. In this case, the velocity field in the limit is the same as in conjugate Poiseuille flow, and the temperature is represented as a polynomial of the fourth order on the radial coordinate.
Доп.точки доступа:
Андреев, Виктор Константинович
Effects of vibrations on dynamics of miscible liquids
[Text] / Y. Gaponenko, V. Shevtsova // Acta Astronaut. - 2010. - Vol. 66, Is. 01.02.2013. - pp. 174-182, DOI 10.1016/j.actaastro.2009.05.019. - Cited References: 10
. - ISSN 0094-5765
РУБ Engineering, Aerospace
Аннотация: We report on a numerical study of the mixing of two miscible fluids in gravitationally stable configuration. In the absence of external forces the diffusion process leads to the mixing of species. The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures of water-isopropanol are imposed. The vibrations with a constant frequency and amplitude are directed along the interface. In absence of gravity vibration-induced mass transport is incomparably faster than in diffusion regime. Our results highlight the strong interplay between gravity and vibrational impact, the relative weight of each effect is determined by ratio vibrational and classical Rayleigh numbers. (C) 2009 Elsevier Ltd. All rights reserved.
Доп.точки доступа:
Gaponenko, Y.; Гапоненко, Юрий Анатольевич; Shevtsova, V.
Аннотация: We report on a numerical study of the mixing of two miscible fluids in gravitationally stable configuration. In the absence of external forces the diffusion process leads to the mixing of species. The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures of water-isopropanol are imposed. The vibrations with a constant frequency and amplitude are directed along the interface. In absence of gravity vibration-induced mass transport is incomparably faster than in diffusion regime. Our results highlight the strong interplay between gravity and vibrational impact, the relative weight of each effect is determined by ratio vibrational and classical Rayleigh numbers. (C) 2009 Elsevier Ltd. All rights reserved.
Доп.точки доступа:
Gaponenko, Y.; Гапоненко, Юрий Анатольевич; Shevtsova, V.
The Joint Motion of Two Binary Mixtures in a Flat Layer
[Текст] : статья / V. K. Andreev // Journal of Siberian Federal University. Mathematics & Physics = Журнал Сибирского федерального университета. Математика и физика. - 2008. - Т. 1, № 4. - С. 349-370
Аннотация: The invariant solution of the equations of thermodiffusional motion is investigated. This solution describes the motion of two immiscible incompressible binary mixtures with a common flat interface under the action of pressure gradient and thermocapillary forces. The stationary flow of such system is found. If the pressure gradient in one of the mixtures tends to zero sufficiently fast, then the motion of mixtures is slowed down by the viscous friction. On the other hand, if there exists a finite limit of pressure gradient when time tends to infinity, then the solution tends to the stationary state.
Полный текст на сайте журнала
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Андреев, Виктор Константинович
Аннотация: The invariant solution of the equations of thermodiffusional motion is investigated. This solution describes the motion of two immiscible incompressible binary mixtures with a common flat interface under the action of pressure gradient and thermocapillary forces. The stationary flow of such system is found. If the pressure gradient in one of the mixtures tends to zero sufficiently fast, then the motion of mixtures is slowed down by the viscous friction. On the other hand, if there exists a finite limit of pressure gradient when time tends to infinity, then the solution tends to the stationary state.
Полный текст на сайте журнала
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Андреев, Виктор Константинович
Evolution of the joint motion of two viscous heat-conducting fluids in a plane layer under the action of an unsteady pressure gradient
[Text] / V. K. Andreev // J. Appl. Mech. Tech. Phys. - 2008. - Vol. 49, Is. 4. - P598-609, DOI 10.1007/s10808-008-0077-4. - Cited References: 4
. - ISSN 0021-8944
РУБ Mechanics + Physics, Applied
Аннотация: A study is made of an invariant solution of the equations of a, viscous heat-conducting fluid; which is treated as unidirectional motion of two such fluids in a plane layer with a common boundary under the action of an unsteady pressure gradient. A priori estimates of the velocity and temperature are obtained. The steady state is determined; and it is shown (under some conditions on the pressure gradient) that, at larger times, this state is the limiting one. For semiinfinite layers; a solution in closed form is obtained using the Laplace transform.
Полный текст на сайте издательства
Доп.точки доступа:
Андреев, Виктор Константинович
Аннотация: A study is made of an invariant solution of the equations of a, viscous heat-conducting fluid; which is treated as unidirectional motion of two such fluids in a plane layer with a common boundary under the action of an unsteady pressure gradient. A priori estimates of the velocity and temperature are obtained. The steady state is determined; and it is shown (under some conditions on the pressure gradient) that, at larger times, this state is the limiting one. For semiinfinite layers; a solution in closed form is obtained using the Laplace transform.
Полный текст на сайте издательства
Доп.точки доступа:
Андреев, Виктор Константинович
On an Adjoint Initial-Boundary Value Problem
[Text] / V. K. Andreev // Differ. Equ. - 2008. - Vol. 44, Is. 12. - P1730-1736, DOI 10.1134/S0012266108120094. - Cited References: 5. - The research was financially supported by Integration Project no. 2.15 of the Siberian Branch of the Russian Academy of Sciences and by the 'Program for the Support of Leading Scientific Schools of the Russian Federation (project no. NSh-587.3.2006.1).
. - ISSN 0012-2661
РУБ Mathematics
Аннотация: We study an adjoint initial-boundary value problem for linear parabolic equations; which arises when modeling the unidirectional motion of two viscous fluids with a common interface under the action of a pressure gradient. Under some conditions on the pressure gradient, we obtain a priori estimates and show that the solution enters a stationary mode. For semi-bounded layers, we find the solution in closed form and indicate the case of a self-similar solution. We determine the volume flow rates in the layers.
Полный текст на сайте издательства
Доп.точки доступа:
Андреев, Виктор Константинович
Аннотация: We study an adjoint initial-boundary value problem for linear parabolic equations; which arises when modeling the unidirectional motion of two viscous fluids with a common interface under the action of a pressure gradient. Under some conditions on the pressure gradient, we obtain a priori estimates and show that the solution enters a stationary mode. For semi-bounded layers, we find the solution in closed form and indicate the case of a self-similar solution. We determine the volume flow rates in the layers.
Полный текст на сайте издательства
Доп.точки доступа:
Андреев, Виктор Константинович
Mixing Under Vibrations in Reduced Gravity
[Text] : статья / Y. A. Gaponenko, V. Shevtsova // Microgravity Science and Technology. - 2008. - Vol. 20, Iss. 3-4 . - p. 307-311, DOI 10.1007/s12217-008-9075-7
. - ISSN 0938-0108
Аннотация: The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two initially stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures (Sc = 7125) are considered. The vibrations with a constant frequency are imposed parallel to the initially planar interface. The ability of the applied vibrations to enhance the flow is examined. At the early stage after imposing the vibrations the Kelvin-Helmholtz instability is observed in absence and at low level of gravity. Later in time the system undergoes a transition to Rayleigh-Taylor instability. With increasing of gravity level the life-time of Kelvin-Helmholtz instability is decreased. We found the critical value of Gr above which this instability do not developed.
Полный текст на сайте журнала
Доп.точки доступа:
Shevtsova, V.; Гапоненко, Юрий Анатольевич
Аннотация: The aim of this study is to analyze the physical mechanism by which vibrations affect the mixing characteristic of two initially stratified miscible fluids. The translational periodic vibrations of a rigid cell filled with different mixtures (Sc = 7125) are considered. The vibrations with a constant frequency are imposed parallel to the initially planar interface. The ability of the applied vibrations to enhance the flow is examined. At the early stage after imposing the vibrations the Kelvin-Helmholtz instability is observed in absence and at low level of gravity. Later in time the system undergoes a transition to Rayleigh-Taylor instability. With increasing of gravity level the life-time of Kelvin-Helmholtz instability is decreased. We found the critical value of Gr above which this instability do not developed.
Полный текст на сайте журнала
Доп.точки доступа:
Shevtsova, V.; Гапоненко, Юрий Анатольевич
Shear driven two-phase flows in vertical cylindrical duct
[Text] : статья / Y. Gaponenko, A. Mialdun, V. Shevtsova // International Journal of Multiphase Flow. - 2012. - Vol. 39. - p. 205-215, DOI 10.1007/s12217-008-9075-7
. - ISSN 0938-0108
Кл.слова (ненормированные):
Gas–liquid flow -- Entrainment -- Interface deformation -- Liquid bridge -- Free surface deformation -- Viscosity contrast
Аннотация: Experiments and numerical simulations were carried out for shear-driven two-phase flows in a confined volume of liquid under conditions of normal gravity. The geometry corresponds to a cylindrical liquid bridge surrounded by a concentric annular gas channel with external solid walls. The internal part consists of solid supports at the bottom and top, while the central part is a liquid zone filled with a viscous liquid and kept in its position by surface tension. Gas enters into the annular duct, flows between solid walls and upon reaching the liquid zone entrains initially quiescent liquid. The flow dynamics is governed by the Navier–Stokes equations in both fluids, which are numerically solved in the exact experimental geometry taking into account interface deformation by gravity. In the experiments 5 cSt silicone oil and air were used as test fluids and the flow was monitored by means of particle tracking velocimetry. The experiments were performed for unit aspect ratio (the ratio of liquid zone length to its radius), while the simulations of shear-driven flow were carried out for a wide range of parameters. A particular attention is focused on the effect of free surface shape and fluids viscosity contrast on the interfacial flow dynamics. The current study suggests a linear dependence between velocities of gas and liquid when the viscosity of the liquid is larger by two orders of magnitude than that of gas. Another relation is proposed when the fluids viscosity ratio, μl/μg, is less than 50.
Полный текст на сайте правообладателя
Доп.точки доступа:
Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Кл.слова (ненормированные):
Gas–liquid flow -- Entrainment -- Interface deformation -- Liquid bridge -- Free surface deformation -- Viscosity contrast
Аннотация: Experiments and numerical simulations were carried out for shear-driven two-phase flows in a confined volume of liquid under conditions of normal gravity. The geometry corresponds to a cylindrical liquid bridge surrounded by a concentric annular gas channel with external solid walls. The internal part consists of solid supports at the bottom and top, while the central part is a liquid zone filled with a viscous liquid and kept in its position by surface tension. Gas enters into the annular duct, flows between solid walls and upon reaching the liquid zone entrains initially quiescent liquid. The flow dynamics is governed by the Navier–Stokes equations in both fluids, which are numerically solved in the exact experimental geometry taking into account interface deformation by gravity. In the experiments 5 cSt silicone oil and air were used as test fluids and the flow was monitored by means of particle tracking velocimetry. The experiments were performed for unit aspect ratio (the ratio of liquid zone length to its radius), while the simulations of shear-driven flow were carried out for a wide range of parameters. A particular attention is focused on the effect of free surface shape and fluids viscosity contrast on the interfacial flow dynamics. The current study suggests a linear dependence between velocities of gas and liquid when the viscosity of the liquid is larger by two orders of magnitude than that of gas. Another relation is proposed when the fluids viscosity ratio, μl/μg, is less than 50.
Полный текст на сайте правообладателя
Доп.точки доступа:
Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Liquid entrainment by gas flow along the interface of a liquid bridge
[Text] : статья / Y. Gaponenko, A. Mialdun, V. Shevtsova // The European Physical Journal Special Topics. - 2011. - Vol. 192, Iss. 1. - p. 63-70, DOI 10.1140/epjst/e2011-01360-0
. - ISSN 1951-6355
Аннотация: We report the results of numerical and experimental studies of two-phase flows in an annulus. The geometry corresponds to a cylindrical liquid column co-axially placed into an outer cylinder with solid walls. Gas enters into the annular duct and entrains the initially quiescent liquid. The internal column consists of solid rods at the bottom and top, while the central part is a liquid bridge from a viscous liquid and kept in its position by surface tension. Silicone oil 5cSt was used as a test liquid and air and nitrogen as gases. An original numerical approach was developed to study the problem in complex geometry. The flow structure in the liquid is analyzed for a wide range of gas flow rates.
Полный текст на сайте правообладателя
Доп.точки доступа:
Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Аннотация: We report the results of numerical and experimental studies of two-phase flows in an annulus. The geometry corresponds to a cylindrical liquid column co-axially placed into an outer cylinder with solid walls. Gas enters into the annular duct and entrains the initially quiescent liquid. The internal column consists of solid rods at the bottom and top, while the central part is a liquid bridge from a viscous liquid and kept in its position by surface tension. Silicone oil 5cSt was used as a test liquid and air and nitrogen as gases. An original numerical approach was developed to study the problem in complex geometry. The flow structure in the liquid is analyzed for a wide range of gas flow rates.
Полный текст на сайте правообладателя
Доп.точки доступа:
Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Study of a liquid bridge subjected to interface shear stresses
[Text] : статья / Y. Gaponenko, S. Glockner, A. Mialdun, V. Shevtsova // Acta Astronautica. - 2011. - Vol. 69, Iss. 3-4. - p. 119-126DOI 10.1016/j.actaastro.2011.03.012
. -
Аннотация: We report on numerical and experimental study of two-phase flows in a tall annulus. The geometry corresponds to a cylindrical liquid column co-axially placed into an outer cylinder with solid walls. The internal column consists of solid supports at the bottom and top, while the central part is a liquid zone filled with viscous liquid and kept in its position by surface tension. Gas enters into the annular duct and entrains initially quiescent liquid. The liquid bridge interface is deformed by gravity and by a co-axial gas flow which is co- and counter directed with respect to gravity. A new experimental set-up including an optical system for precise measurements of the interface displacement has been designed and developed. In the experiments silicone oil 5cSt was used as a test liquid and air as gas. On numerical side the dynamical response of an isothermal liquid bridge to a coaxial gas flow is examined by simulations of the Navier–Stokes equations. The attention is focused on the following points: time-dependent formation of the equilibrium shape of a liquid bridge in gravity conditions and its deformation by a gas flow, simulation of a flow pattern in a liquid/gas system with deformed free surface. The comparison of the numerical and experimental results for the interface deformation exhibits a satisfactory agreement.
Полный текст на сайте правообладателя
Доп.точки доступа:
Glockner, S.; Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Аннотация: We report on numerical and experimental study of two-phase flows in a tall annulus. The geometry corresponds to a cylindrical liquid column co-axially placed into an outer cylinder with solid walls. The internal column consists of solid supports at the bottom and top, while the central part is a liquid zone filled with viscous liquid and kept in its position by surface tension. Gas enters into the annular duct and entrains initially quiescent liquid. The liquid bridge interface is deformed by gravity and by a co-axial gas flow which is co- and counter directed with respect to gravity. A new experimental set-up including an optical system for precise measurements of the interface displacement has been designed and developed. In the experiments silicone oil 5cSt was used as a test liquid and air as gas. On numerical side the dynamical response of an isothermal liquid bridge to a coaxial gas flow is examined by simulations of the Navier–Stokes equations. The attention is focused on the following points: time-dependent formation of the equilibrium shape of a liquid bridge in gravity conditions and its deformation by a gas flow, simulation of a flow pattern in a liquid/gas system with deformed free surface. The comparison of the numerical and experimental results for the interface deformation exhibits a satisfactory agreement.
Полный текст на сайте правообладателя
Доп.точки доступа:
Glockner, S.; Mialdun, A.; Shevtsova, V.; Гапоненко, Юрий Анатольевич
Change of the types of instability of a steady two-layer flow in an inclined channel
[Text] : статья / V. B. Bekezhanova // Fluid Dynamics. - 2011. - Vol. 46, Iss. 4. - p. 525-535DOI 10.1134/S001546281104003X
. -
Аннотация: A plane steady-state two-layer fluid flow under the coupled action of the buoyancy and Marangoni forces is considered. The system is oriented at an arbitrary angle with respect to the gravity force. Exact solutions generalizing the Ostroumov-Birikh solution are obtained and their stability is studied in the framework of a linear theory. On the basis of numerical calculations, the influence of the inclination angle, the thickness of the layers, and the wall heating conditions on the instability mechanisms is investigated.
Полный текст на сайте правообладателя
Доп.точки доступа:
Бекежанова, Виктория Бахытовна
Аннотация: A plane steady-state two-layer fluid flow under the coupled action of the buoyancy and Marangoni forces is considered. The system is oriented at an arbitrary angle with respect to the gravity force. Exact solutions generalizing the Ostroumov-Birikh solution are obtained and their stability is studied in the framework of a linear theory. On the basis of numerical calculations, the influence of the inclination angle, the thickness of the layers, and the wall heating conditions on the instability mechanisms is investigated.
Полный текст на сайте правообладателя
Доп.точки доступа:
Бекежанова, Виктория Бахытовна
Some adaptive numerical technology for computational aerodynamics
/ V. Shaydurov, T. Liu // Procedia Eng. - 2013. - Vol. 61: 25th International Conference on Parallel Computational Fluid Dynamics, ParCFD 2013 (20 May 2013 through 24 May 2013, Changsha) Conference code: 101818. - P16-22, DOI 10.1016/j.proeng.2013.07.086
. -
Кл.слова (ненормированные):
Four-stage computational technology -- Heat-conducting gas -- High-order solvers -- Time-dependent Navier-Stokes equations
Аннотация: All three components of computational aerodynamics are actively developed: mathematical models of real aerodynamic processes, numerical algorithms, and high-performance computing. The most impressive progress has been made in the field of computing, though with a considerable complication of the computer architecture. Numerical algorithms developed more conservative. Nevertheless, computational mathematics now amassed a whole palette of numerical algorithms that can provide acceptable accuracy and interface between modern mathematical models in aerodynamics and high-performance computers. This paper gives a general overview of objectives and approaches of international Project TRISTAM and a description of the four-stage computer technology in the field of computational aerodynamics. © 2013 The Authors.
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Держатели документа:
Beihang University, 37# Xueyuan Road, Haidian District, Beijing, 100191, China
Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, 50/44 Akademgorodok, Krasnoyarsk, 660036, Russian Federation
ИВМ СО РАН
Доп.точки доступа:
Liu, T.; Шайдуров, Владимир Викторович
Кл.слова (ненормированные):
Four-stage computational technology -- Heat-conducting gas -- High-order solvers -- Time-dependent Navier-Stokes equations
Аннотация: All three components of computational aerodynamics are actively developed: mathematical models of real aerodynamic processes, numerical algorithms, and high-performance computing. The most impressive progress has been made in the field of computing, though with a considerable complication of the computer architecture. Numerical algorithms developed more conservative. Nevertheless, computational mathematics now amassed a whole palette of numerical algorithms that can provide acceptable accuracy and interface between modern mathematical models in aerodynamics and high-performance computers. This paper gives a general overview of objectives and approaches of international Project TRISTAM and a description of the four-stage computer technology in the field of computational aerodynamics. © 2013 The Authors.
Scopus
Держатели документа:
Beihang University, 37# Xueyuan Road, Haidian District, Beijing, 100191, China
Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, 50/44 Akademgorodok, Krasnoyarsk, 660036, Russian Federation
ИВМ СО РАН
Доп.точки доступа:
Liu, T.; Шайдуров, Владимир Викторович
Three-dimensional disturbances of a plane-parallel two-layer flow of a viscous, heat-conducting fluid
[Text] : статья / V. B. Bekezhanova // Fluid Dynamics. - 2012. - Vol. 47, Iss. 6. - p. 702-708DOI 10.1134/S0015462812060038
. -
Аннотация: The stability of the Marangoni-Poiseuille flow in an inclined channel against three-dimensional disturbances is studied. It is shown that the nature of instability is determined by wall heating conditions and the system orientation with respect to its horizontal position. With variation in the angle of inclination of the system spiral disturbances leading to the system crisis can develop.
Полный текст на сайте правообладателя
Доп.точки доступа:
Бекежанова, Виктория Бахытовна
Аннотация: The stability of the Marangoni-Poiseuille flow in an inclined channel against three-dimensional disturbances is studied. It is shown that the nature of instability is determined by wall heating conditions and the system orientation with respect to its horizontal position. With variation in the angle of inclination of the system spiral disturbances leading to the system crisis can develop.
Полный текст на сайте правообладателя
Доп.точки доступа:
Бекежанова, Виктория Бахытовна
Thermocapillary instabilities in liquid columns under co – and counter-current gas flows
/ I. I. Ryzhkov, V. M. Shevtsova // International Journal of Heat and Mass Transfer. - 2012. - Vol. 55, Is. 4. - pp. 1236–1245, DOI 10.1016/j.ijheatmasstransfer.2011.09.030
. - ISSN 0017-9310
Кл.слова (ненормированные):
Thermocapillary instability -- Liquid column -- Two-phase flow -- Linear stability
Аннотация: The thermocapillary flows in an infinite liquid column surrounded by an annular channel of gas with the axial temperature gradient are investigated. The gas is pumped through the channel parallel to the interface with a given flow rate. The solution for stationary motion is derived and possible flow regimes are analyzed depending on the Marangoni number and dimensionless gas flow rate. Linear stability analysis of these regimes is performed. It is shown that gas pumping in the same direction with respect to the thermocapillary motion on the interface has a destabilizing effect on the system. Gas pumping in the opposite direction can be stabilizing or destabilizing depending on the gas flow rate. It is shown that the motion of liquid can be completely vanished by the gas flow with a specified flow rate. The obtained results demonstrate the possibility of controlling thermocapillary flows and their stability in liquid columns (liquid bridges) by gas flows.
Полный текст на сайте правообладателя
Доп.точки доступа:
Shevtsova, V.M.; Рыжков, Илья Игоревич
Кл.слова (ненормированные):
Thermocapillary instability -- Liquid column -- Two-phase flow -- Linear stability
Аннотация: The thermocapillary flows in an infinite liquid column surrounded by an annular channel of gas with the axial temperature gradient are investigated. The gas is pumped through the channel parallel to the interface with a given flow rate. The solution for stationary motion is derived and possible flow regimes are analyzed depending on the Marangoni number and dimensionless gas flow rate. Linear stability analysis of these regimes is performed. It is shown that gas pumping in the same direction with respect to the thermocapillary motion on the interface has a destabilizing effect on the system. Gas pumping in the opposite direction can be stabilizing or destabilizing depending on the gas flow rate. It is shown that the motion of liquid can be completely vanished by the gas flow with a specified flow rate. The obtained results demonstrate the possibility of controlling thermocapillary flows and their stability in liquid columns (liquid bridges) by gas flows.
Полный текст на сайте правообладателя
Доп.точки доступа:
Shevtsova, V.M.; Рыжков, Илья Игоревич
On Thermocapillary Instability of a Liquid Column with a Co-axial Gas Flow
[Текст] : статья / V. K. Andreev, I. I. Ryzhkov // Journal of Siberian Federal University. Mathematics & Physics = Журнал Сибирского федерального университета. Математика и физика. - 2013. - Т. 6, № 1. - С. 3-17
Перевод заглавия: О термокапиллярной неустойчивости жидкого цилиндра, обдуваемого потоком газа
Аннотация: The thermocapillary flows and their stability in an infinite liquid column surrounded by a co–axial gas layer with a given flow rate are investigated. The gas layer is surrounded by a rigid cylindrical surface, which can move in vertical direction. A constant axial temperature gradient is maintained in the layers. The exact solution describing the stationary flow in the given two–phase system is derived. Possible flow regimes are investigated and linear stability analysis of these regimes is performed. The cases of non–deformable and deformable interface are studied.
Полный текст на сайте журнала
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Андреев, Виктор Константинович
Перевод заглавия: О термокапиллярной неустойчивости жидкого цилиндра, обдуваемого потоком газа
Аннотация: The thermocapillary flows and their stability in an infinite liquid column surrounded by a co–axial gas layer with a given flow rate are investigated. The gas layer is surrounded by a rigid cylindrical surface, which can move in vertical direction. A constant axial temperature gradient is maintained in the layers. The exact solution describing the stationary flow in the given two–phase system is derived. Possible flow regimes are investigated and linear stability analysis of these regimes is performed. The cases of non–deformable and deformable interface are studied.
Полный текст на сайте журнала
Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44
Доп.точки доступа:
Ryzhkov, I.I.; Рыжков, Илья Игоревич; Андреев, Виктор Константинович
Axisymmetric thermocapillary motion in a cylinder at small marangoni number
/ E. P. Magdenko // J. Sib. Fed. Univ. Math. Phys. - 2015. - Vol. 8, Is. 3. - P303-311, DOI 10.17516/1997-1397-2015-8-3-303-311
. - ISSN 1997-1397
Кл.слова (ненормированные):
Fluid-fluid interface -- Inverse problem -- Laplace transform -- Thermocapillary motion
Аннотация: The solution to the linear problem of axisymmetric thermocapillary motion of two non-miscible vis-cous fluids in a cylindrical tube is presented. Their common interface is fixed and undeformable. This problem is an inverse problem because pressure gradients are unknown functions. The solution of the non-stationary problem is presented in the form of analytical expressions. They are obtained with the use of the method of Laplace transformation. If the wall temperature is stabilized then the general solution tends to the stationary solution as time increases. Numerical calculations confirm the theoretical results. © Siberian Federal University. All rights reserved.
Scopus
Держатели документа:
Institute of Computational Modeling SB RAS, Akademgorodok, 50/44, Krasnoyarsk, Russian Federation
Доп.точки доступа:
Magdenko, E. P.; Магденко, Евгений Петрович
Кл.слова (ненормированные):
Fluid-fluid interface -- Inverse problem -- Laplace transform -- Thermocapillary motion
Аннотация: The solution to the linear problem of axisymmetric thermocapillary motion of two non-miscible vis-cous fluids in a cylindrical tube is presented. Their common interface is fixed and undeformable. This problem is an inverse problem because pressure gradients are unknown functions. The solution of the non-stationary problem is presented in the form of analytical expressions. They are obtained with the use of the method of Laplace transformation. If the wall temperature is stabilized then the general solution tends to the stationary solution as time increases. Numerical calculations confirm the theoretical results. © Siberian Federal University. All rights reserved.
Scopus
Держатели документа:
Institute of Computational Modeling SB RAS, Akademgorodok, 50/44, Krasnoyarsk, Russian Federation
Доп.точки доступа:
Magdenko, E. P.; Магденко, Евгений Петрович
Longwave stability of two-layer fluid flow in the inclined plane
/ V. B. Bekezhanova, A. V. Rodionova // Fluid Dyn. - 2015. - Vol. 50, Is. 6. - P723-736, DOI 10.1134/S0015462815060010
. - ISSN 0015-4628
Кл.слова (ненормированные):
interface -- spectrum of characteristic perturbations -- stability -- Capillary flow -- Convergence of numerical methods -- Eigenvalues and eigenfunctions -- Fluid dynamics -- Interfaces (materials) -- Machinery -- Inclined planes -- Long-wave stabilities -- Oscillatory regimes -- Spectral problem -- spectrum of characteristic perturbations -- Thermocapillary flow -- Two layer fluid -- Zeroth approximations -- Flow of fluids
Аннотация: The exact invariantOstroumov–Birikh solution of the Oberbeck–Bussinesq equationswhich describes two-layer advective thermocapillary flows in the inclined plane is analyzed. The spectrum of the characteristic perturbations of all classes of the flows is investigated and analytical representations of the eigennumbers and eigenfunctions of the corresponding spectral problem are obtained in the zeroth approximation. Stability of the flows with respect to longwave perturbations and the possibility of existence of oscillatory regimes are proved. © 2015, Pleiades Publishing, Ltd.
Scopus,
WOS
Держатели документа:
Institute of Computational Modelling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50, Krasnoyarsk, Russian Federation
Institute of Mathematics and Basic Informatics of the Siberian Federal University, pr. Svobodnyi 79, Krasnoyarsk, Russian Federation
Доп.точки доступа:
Rodionova, A. V.; Бекежанова, Виктория Бахытовна
Кл.слова (ненормированные):
interface -- spectrum of characteristic perturbations -- stability -- Capillary flow -- Convergence of numerical methods -- Eigenvalues and eigenfunctions -- Fluid dynamics -- Interfaces (materials) -- Machinery -- Inclined planes -- Long-wave stabilities -- Oscillatory regimes -- Spectral problem -- spectrum of characteristic perturbations -- Thermocapillary flow -- Two layer fluid -- Zeroth approximations -- Flow of fluids
Аннотация: The exact invariantOstroumov–Birikh solution of the Oberbeck–Bussinesq equationswhich describes two-layer advective thermocapillary flows in the inclined plane is analyzed. The spectrum of the characteristic perturbations of all classes of the flows is investigated and analytical representations of the eigennumbers and eigenfunctions of the corresponding spectral problem are obtained in the zeroth approximation. Stability of the flows with respect to longwave perturbations and the possibility of existence of oscillatory regimes are proved. © 2015, Pleiades Publishing, Ltd.
Scopus,
WOS
Держатели документа:
Institute of Computational Modelling, Siberian Branch, Russian Academy of Sciences, Akademgorodok 50, Krasnoyarsk, Russian Federation
Institute of Mathematics and Basic Informatics of the Siberian Federal University, pr. Svobodnyi 79, Krasnoyarsk, Russian Federation
Доп.точки доступа:
Rodionova, A. V.; Бекежанова, Виктория Бахытовна
539.3
К 65
К 65
Контроль точности решения при анализе напряженно-деформированного состояния высокоответственных технических объектов
[Текст] : статья / А. Н. Рогалев, С. В. Доронин, А. А. Рогалев // Системы. Методы. Технологии. - 2015. - № 3. - С. 32-38
. - ISSN 2077-5415
Перевод заглавия: Solution accuracy control for analysis of stress-strain state of critical technical objects
Кл.слова (ненормированные):
вычислительная ошибка -- матрица жесткости -- моделирование -- система линейных алгебраических уравнений -- контроль точности -- Numerical error -- Stiffness matrix -- modeling -- System of linear equations -- accuracy control
Аннотация: В статье рассматриваются подходы к оценке вычислительной ошибки при решении системы линейных алгебраических уравнений, в качестве матрицы коэффициентов которой рассматривается матрица жесткости конечно-элементной модели технического объекта. Предлагаемый подход предполагает, что уровень вычислительной ошибки определяется структурой и значениями матрицы коэффициентов, и заключается в численном решении системы линейных уравнений с матрицей жесткости и такой специально подобранной правой частью, для которой известно точное решение. Сравнение численного и точного решений позволяет получить оценку вычислительной ошибки, позволяющую судить о приемлемости построенной конечно-элементной модели. Получение указанной оценки является дополнительной процедурой контроля точности численного решения при анализе его сходимости путем последовательного уменьшения шага конечных элементов. Развиваемый подход весьма актуален для конструкций ответственных технических объектов, где цена ошибки при проектных расчетах оказывается неприемлемо высокой. Для реализации предлагаемого подхода организован интерфейс между пакетом конечно-элементного моделирования ANSYS и вычислительным пакетом компьютерной алгебры Wolfram Mathematica. В качестве примера приводится получение оценки вычислительной ошибки численного решения системы линейных алгебраических уравнений с матрицей жесткости силовой конструкции бака высокого давления для перспективных электрореактивных двигателей космических аппаратов. Силовая конструкция представляет собой оболочку давления, подвешенную на системе вантов с регулируемым уровнем натяжения, закрепленных, в свою очередь, на пространственной стержневой системе - силовой структуре корпуса космического аппарата. Для рассматриваемой конструкции найден уровень конечно-элементной дискретизации, обеспечивающий сходимость численного решения.
The paper is devoted to approaches to a problem of numerical error evaluation when solving the system of linear equations. The stiffness matrix of a finite-element model of a technical object is a coefficient matrix of the system of linear equations. The approach proposed supposes that the level of numerical error is determined by a structure and magnitude of coefficient matrix. The approach consists of numerical solving system of linear equations with stiffness matrix and special right-hand member with exact solution known. Comparison of numerical and exact solutions allows evaluating numerical error and making decision on the quality of finite-element model. Evaluation numerical error is a supplementary procedure for checking accuracy of numerical solution within solution convergence analysis by means of cascade reduction mesh spacing. The approach is of great actuality for structures of critical technical objects with great worth of design calculations error. To implement the approach, data interface between the finite-element analysis package ANSYS and computer algebra package Wolfram Mathematica has been created. Evaluated numerical error has been given as an example for numerical solution system of linear equations with stiffness matrix for load-bearing unit of high pressure tank for perspective spacecraft electrojet engines. The load-bearing unit consists of pressure shell suspended by means of cable system with controlled tension. The cable system is attached to spatial bar system - load-bearing frame structure of spacecraft. For the structures considered the level of finite-element discretization has been determined to provide numerical solution convergence.
РИНЦ
Держатели документа:
Институт вычислительного моделирования СО РАН
Институт космических и информационных технологий Сибирского федерального университета
Специальное конструкторско-технологическое бюро «Наука» Красноярского научного центра СО РАН
Доп.точки доступа:
Доронин, С.В.; Doronin S.V.; Рогалев, А.А.; Rogalyov A.A.; Rogalyov A.N.
Перевод заглавия: Solution accuracy control for analysis of stress-strain state of critical technical objects
| УДК |
Кл.слова (ненормированные):
вычислительная ошибка -- матрица жесткости -- моделирование -- система линейных алгебраических уравнений -- контроль точности -- Numerical error -- Stiffness matrix -- modeling -- System of linear equations -- accuracy control
Аннотация: В статье рассматриваются подходы к оценке вычислительной ошибки при решении системы линейных алгебраических уравнений, в качестве матрицы коэффициентов которой рассматривается матрица жесткости конечно-элементной модели технического объекта. Предлагаемый подход предполагает, что уровень вычислительной ошибки определяется структурой и значениями матрицы коэффициентов, и заключается в численном решении системы линейных уравнений с матрицей жесткости и такой специально подобранной правой частью, для которой известно точное решение. Сравнение численного и точного решений позволяет получить оценку вычислительной ошибки, позволяющую судить о приемлемости построенной конечно-элементной модели. Получение указанной оценки является дополнительной процедурой контроля точности численного решения при анализе его сходимости путем последовательного уменьшения шага конечных элементов. Развиваемый подход весьма актуален для конструкций ответственных технических объектов, где цена ошибки при проектных расчетах оказывается неприемлемо высокой. Для реализации предлагаемого подхода организован интерфейс между пакетом конечно-элементного моделирования ANSYS и вычислительным пакетом компьютерной алгебры Wolfram Mathematica. В качестве примера приводится получение оценки вычислительной ошибки численного решения системы линейных алгебраических уравнений с матрицей жесткости силовой конструкции бака высокого давления для перспективных электрореактивных двигателей космических аппаратов. Силовая конструкция представляет собой оболочку давления, подвешенную на системе вантов с регулируемым уровнем натяжения, закрепленных, в свою очередь, на пространственной стержневой системе - силовой структуре корпуса космического аппарата. Для рассматриваемой конструкции найден уровень конечно-элементной дискретизации, обеспечивающий сходимость численного решения.
The paper is devoted to approaches to a problem of numerical error evaluation when solving the system of linear equations. The stiffness matrix of a finite-element model of a technical object is a coefficient matrix of the system of linear equations. The approach proposed supposes that the level of numerical error is determined by a structure and magnitude of coefficient matrix. The approach consists of numerical solving system of linear equations with stiffness matrix and special right-hand member with exact solution known. Comparison of numerical and exact solutions allows evaluating numerical error and making decision on the quality of finite-element model. Evaluation numerical error is a supplementary procedure for checking accuracy of numerical solution within solution convergence analysis by means of cascade reduction mesh spacing. The approach is of great actuality for structures of critical technical objects with great worth of design calculations error. To implement the approach, data interface between the finite-element analysis package ANSYS and computer algebra package Wolfram Mathematica has been created. Evaluated numerical error has been given as an example for numerical solution system of linear equations with stiffness matrix for load-bearing unit of high pressure tank for perspective spacecraft electrojet engines. The load-bearing unit consists of pressure shell suspended by means of cable system with controlled tension. The cable system is attached to spatial bar system - load-bearing frame structure of spacecraft. For the structures considered the level of finite-element discretization has been determined to provide numerical solution convergence.
РИНЦ
Держатели документа:
Институт вычислительного моделирования СО РАН
Институт космических и информационных технологий Сибирского федерального университета
Специальное конструкторско-технологическое бюро «Наука» Красноярского научного центра СО РАН
Доп.точки доступа:
Доронин, С.В.; Doronin S.V.; Рогалев, А.А.; Rogalyov A.A.; Rogalyov A.N.