Труды сотрудников ИВМ СО РАН

[Text]. - Electronic data (106 Kb)
. - Режим доступа: http://icm.krasn.ru/refextra.php?id=1472. - Электрон. версия печ. публикации . - Режим доступа: http://library.krasn.ru/trudy/2000/1472erkaev_PHP03413_eng.pdf (Полный текст) : статья / Erkaev N.V., Biernat H.K., Farrugia C.J. - Electronic data (106 Kb) // Physics of Plasmas. - 2000. - Vol. 7, № 7. - p. 3413-3420

ГРНТИ

29.27.45

Аннотация: The plasma flow past a blunt obstacle in an ideal magnetohydrodynamic ~MHD! model is studied, taking into account the tensorial nature of the plasma pressure. Three different closure relations are explored and compared with one another. The first one is the adiabatic model proposed by Chew, Goldberger, and Low. The second closure is based on the mirror instability criterion, while the third depends on an empirical closure equation obtained from observations of solar wind flow past the Earth's magnetosphere. The latter is related with the criterion of the anisotropic ion cyclotron instability. In the presented model, the total pressure, defined as the sum of magnetic pressure and perpendicular plasma pressure, is assumed to be a known function of Cartesian coordinates. The calculation is based on the Newtonian approximation for the total pressure along the obstacle and on a quadratic behavior with distance from the obstacle along the normal direction. Profiles of magnetic field strength and plasma parameters are presented along the stagnation stream line between the shock and obstacle of an ideal plasma flow with anisotropy in thermal pressure and temperature.

http://icm.krasn.ru/refextra.php?id=1472,
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Держатели документа:
ИВМ СО РАН : 660036, Красноярск, Академгородок, 50, стр.44

Доп.точки доступа:
Biernat, H.K.; Farrugia, C.J.; Еркаев, Николай Васильевич

/ A.V. Vyatkin // Autom. Remote Control. - 2013. - Vol. 74, Is. 2. - P325-330, DOI 10.1134/S0005117913020173. - Cited References: 9. - This work was supported by the Russian Foundation for Basic Research, project no. 08-01-00621, and by the Russian President's Program, project no. NSh-3431.2008.9. . - 6. - ISSN 0005-1179РУБ Automation & Control Systems + Instruments & Instrumentation

Аннотация: The behavior of the explicit Runge-Kutta methods having the second, fourth and eighth orders of accuracy is analyzed at the singular point in the two-body problem. Numerical solutions are compared with their analytical counterpart. As the adequacy criterion for an approximate solution, the conservation law of the total mechanical energy is considered.


Доп.точки доступа:
Vyatkin, A.V.; Вяткин, Александр Владимирович

[Text] / D. F. Vogl [et al.] // Nonlinear Process Geophys. - 2001. - Vol. 8: 25th General Assembly of the European-Geophysical-Society (APR, 2000, NICE, FRANCE), Is. 3. - P167-174. - Cited References: 16 . - ISSN 1023-5809РУБ Geochemistry & Geophysics + Meteorology & Atmospheric Sciences

Аннотация: Taking into account the pressure anisotropy in the solar wind, we study the magnetic field and plasma parameters downstream of a fast shock, as functions of upstream parameters and downstream pressure anisotropy. In our theoretical approach, we model two cases: a) the perpendicular shock and b) the oblique shock. We use two threshold conditions of plasma instabilities as additional equations to bound the range of pressure anisotropy. The criterion of the mirror instability is used for pressure anisotropy P (perpendicular to)/P (parallel to) 1. Analogously, the criterion of the fire-hose instability is taken into account for pressure anisotropy P-perpendicular to/P-parallel to 1. We found that the variations of the parallel pressure, the parallel temperature, and the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock. Finally, we compare our theory with plasma and magnetic field parameters measured by the WIND spacecraft.


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

[Text] / D. F. Vogl [et al.] // PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE BV, 2001. - Vol. 28: D3 1/C3 3 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly (JUL, 2000, WARSAW, POLAND), Is. 6. - P851-856, DOI 10.1016/S0273-1177(01)00503-8. - Cited References: 12 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: In this paper we report on the variations of the magnetic field strength and the plasma parameters across a fast shock as functions of upstream Alfven Mach numbers and pressure anisotropy downstream of the shock. In our study we consider an oblique shock where the angle between the magnetic field vector and the normal vector upstream of the shock is chosen to be 45degrees. We further use two threshold conditions of plasma instabilities as additional equations to bound the range of the pressure anisotropy, p(perpendicular to)/p(\\), i.e., the criterion of the mirror instability and that of the fire-hose instability. We found that the variations of the parallel pressure, the parallel temperature, as well as the tangential component of the velocity are most sensitive to the pressure anisotropy downstream of the shock, whereas the variations of the plasma density, the normal velocity, the magnetic field strength, and perpendicular pressure and temperature with respect to the magnetic field show much less pronounced dependence on the anisotropy. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


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

[Text] / N. V. Erkaev [et al.] // PLANETARY MAGNETOSPHERES. Ser. ADVANCES IN SPACE RESEARCH : ELSEVIER SCIENCE BV, 2001. - Vol. 28: D3 1/C3 3 Symposium of COSPAR Scientific Commission D held at the 33rd COSPAR Scientific Assembly (JUL, 2000, WARSAW, POLAND), Is. 6. - P873-877, DOI 10.1016/S0273-1177(01)00522-1. - Cited References: 16 . - ISBN 0273-1177РУБ Engineering, Aerospace + Astronomy & Astrophysics + Geosciences, Multidisciplinary + Meteorology & Atmospheric Sciences

Аннотация: We study the solar wind flow in the Earth's magnetosheath using a three-dimensional, ideal magnetohydrodynamic (MHD) model with anisotropic plasma pressure. Four different closure relations are examined and compared with each other, i) The double adiabatic model; ii) the empirical relation with respect to the criterion of the anisotropic ion cyclotron instability; iii) the mirror instability criterion, and (iv) the combination of the mirror and the anisotropic ion cyclotron instability. Profiles of magnetic field strength and plasma parameters for the different closure relations are presented and compared with each other along the stagnation stream line between the shock and the obstacle. We find that the main body of the magnetosheath is mirror unstable. This is a reason to combine both, mirror and ion cyclotron instability criteria to close the ideal MHD model. (C) 2001 COSPAR. Published by Elsevier Science Ltd. All rights reserved.


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

[Text] / C. J. Farrugia, N. V. Erkaev, H. K. Biernat // J. Geophys. Res-Space Phys. - 2000. - Vol. 105, Is. A1. - P115-127, DOI 10.1029/1999JA900350. - Cited References: 26 . - ISSN 0148-0227РУБ Astronomy & Astrophysics

Аннотация: We apply our recent three-dimensional anisotropic MHD model of magnetosheath flow [Erkaev et al., 1999] to study quantitatively effects of solar wind dynamic pressure (P-d infinity) and Alfven Mach number (M-a infinity) on the anisotropic magnetosheath and the plasma depletion layer (PDL) in the subsolar region. Given the wide range over which these two parameters vary, their influence on the magnetosheath structure may be significant. Our analysis is applicable to quasisteady changes in the interplanetary medium. Following our earlier work; and in general agreement with the data, we define the sunward edge of the PDL by beta(parallel to) = 1, where pll is the proton beta parallel to the magnetic field. We first discuss changes in P-d infinity occurring under constant M-a infinity. In this case, a rescaling of the parameters yields the effects on the magnetosheath. We then study quantitatively a changing dynamic pressure through a varying Alfven Mach number. We obtain profiles of key magnetosheath parameters and the width of the PDL for Alfven Mach numbers representative of the solar wind at Earth orbit. Gradients in parameter profiles become steeper and shift toward the magnetopause as M-a infinity increases. We find that PDL width varies as 1/M-a infinity(2) even in the anisotropic magnetosheath. Using our model to study the magnetosheath location where the electromagnetic ion cyclotron wave (EICW) instability dominates over the mirror instability, we find that this location occurs well inside the PDL. In addition, we estimated the fraction of the PDL width occupied by the EICWs as a function of solar wind Alfven Mach number. We conclude that the EICW regime is contained in, but is not co-extensive with, the PDL. Examining critically this issue by changing the PDL identification criterion to others based on a density decrease relative to the bow shock value and a systematic drop toward the magnetopause, we find that this result still holds, but the region where EICWs are destabilized occupies a different fraction of the PDL thus defined. Some model results are compared with documented data from an inbound crossing of the magnetosheath made on December 24, 1994. Good agreement with model predictions are obtained.


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

[] / S. N. Kozulin, V. I. Senashov // Russ. Math. - 2014. - Vol. 58, Is. 2. - P13-23, DOI 10.3103/S1066369X14020030 . - ISSN 1066-369X
Аннотация: This paper continues the study of the class of Mp-groups introduced by V. P. Shunkov. We obtain a criterion of nonsimplicity of an infinite group which contains anMp-group and contains no group of quaternions. We also obtain a criterion for an infinite group to be an Mp-group. © 2014 Allerton Press, Inc.

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Держатели документа:
VTB24 Lizing Joint Stock Ccompany, Daev per. 20, Moscow 107045, Russian Federation
Institute of Computational Modelling, Siberian Branch of the Russian Academy of Sciences, Akademgorodok 50/44, Krasnoyarsk 660036, Russian Federation
Siberian Federal University, 79 Svobodnyi pr. 79, Krasnoyarsk 660041, Russian Federation

Доп.точки доступа:
Kozulin, S.N.; Senashov, V.I.; Сенашов, Владимир Иванович

/ S. P. Shary // Mathematics and Computers in Simulation. - 1995. - Vol. 39, Is. 1-2. - P53-85 . - ISSN 0378-4754
Аннотация: For the interval linear system Ax = b, the linear tolerance problem is considered that requires inner evaluation of the tolerable solution set ???(A, b) = {x ? Rn {divides} (?A ? A)(Ax ? b)} formed by all point vectors x such that the product Ax remains within b for all possible A ? A. Along with the simple incompatibility criterion, we develop comprehensive solvability theory for the linear tolerance problem that not only settles whether ??? is empty or not, but also enables modification of the problem to ensure its desired properties. To conclude, we advance several numerical methods of various accuracy and complexity for construction of an interval solution to the linear tolerance problem around a given center. В© 1995.

Scopus

Держатели документа:
Computer Center, Siberian Department, Russian Academy of Sciences, Akademgorodok, 660036 Krasnoyarsk, Russian Federation
ИВМ СО РАН

Доп.точки доступа:
Shary, S.P.; Шарый С.П.

/ A. Shevyrgonov, G. Vysotskaya, E. Shevyrgonov // Advances in Space Research. - 2002. - Vol. 30, Is. 11. - P. 2541-2546, DOI 10.1016/S0273-1177(02)80334-9 . - ISSN 0273-1177
Аннотация: The work presents long-standing CZCS-satellite-based data about spatial distribution of anomalies in chlorophyll concentration and temperature of the ocean. An anomaly criterion is proposed. Maps of Atlantic ocean areas with elevated probability of anomalies are given. Properties of anomalous zones in different parts of the Atlantic ocean are discussed. Satellite-based maps of anomaly coefficients for chlorophyll concentration and temperature in the Atlantic ocean have been shown to feature substantial differences, the zones of elevated anomaly of chlorophyll concentration and temperature - to be close only in the vicinity of the Amazon outflow into the Atlantic ocean. Along with fundamental knowledge about dynamics of biological phenomena in the ocean the methods described may be used to reveal deviations due to anthropogenic impact. The methods presented may be used to process SeaWiFS prograna data. The data derived may be used to analyze long-standing time series to estimate randomness of cunent changes. В©2002 COSPAR. Published by Elsevier Science Ltd. All rights reserved.

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Доп.точки доступа:
Shevyrgonov, A.; Vysotskaya, G.; Высоцкая, Галина Степановна; Shevyrgonov, E.

/ A. Shevyrnogov, G. Vysotskaya, E. Shevyrnogov // Advances in Space Research. - 2004. - Vol. 33, Is. 7. - P. 1179-1183, DOI 10.1016/S0273-1177(03)00369-7 . - ISSN 0273-1177
Аннотация: The work presents the data on the spatial distribution of temperature anomalies in the Global Ocean, based on the long-term measurements with the AVHRR satellite equipment. It is noteworthy that such results can be only obtained by using long time series of satellite images. To obtain them by ship-borne methods is actually impossible. The proposed anomaly criterion is equal to a difference between minimum/maximum and average temperature, normed for the mean square deviation. The difference is calculated from the whole time series (with regard to a season). Based on this criterion, anomalies can be distinguished on the background of usual seasonal dynamics at various absolute values of deviations of the measured parameter. Besides, rare, single, fluctuations can be also revealed. Based on the proposed criterion, connected zones have been defined. These zones occur almost in every part of the Global Ocean. The data obtained have been analyzed in association with the CZCS (1978-1986) and SeaWiFS satellite images in order to compare them with the areas of anomalous dynamics of chlorophyll concentration and the regions quasistationary in the seasonal dynamics of chlorophyll. Anomalies in the temperature dynamics are of exceptional importance for the formation of climatic deviations; they affect the ocean-atmosphere interaction and reflect variations in the hydrological structure of the surface waters. The work presents a comparison with the dynamics of chlorophyll concentration distribution determined from the SeaWiFS data for the Atlantic Ocean. В© 2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

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Доп.точки доступа:
Shevyrnogov, A.; Vysotskaya, G.; Высоцкая, Галина Степановна; Shevyrnogov, E.

/ E. A. Novikov, A. E. Novikov // Int. J. Math. Models Methods Appl. Sci. - 2015. - Vol. 9. - P62-70 . - ISSN 1998-0140
Аннотация: An algorithm of variable structure for solving stiff problems is constructed using L-stable and explicit methods. It is based on explicit and L-stable methods, both schemes of order two, and on an explicit method of the first order, which interval of stability is extended. On each step an efficient numerical scheme is chosen by criterion of stability. The numerical results of modeling the simplest oregonator and the modified oregonator exhibiting complicated limit cycle are given. © 2015, North Atlantic University Union NAUN. All rights reserved.

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Держатели документа:
Institute of Computational Modelling Siberian Branch of Russian Academy of ScienceAkademgorodok, Krasnoyarsk, Russian Federation
Siberian Federal University, Svobodny pr.Krasnoyarsk, Russian Federation
ИВМ СО РАН

Доп.точки доступа:
Novikov, E.A.; Новиков, Евгений Александрович; Novikov, A.E.; Новиков, Антон Евгеньевич

/ A. V. Lapko, V. A. Lapko // Measurement Techniques. - 2015, DOI 10.1007/s11018-015-0741-z . - ISSN 0543-1972
Аннотация: A method is proposed for comparing the efficiencies of procedures for sampling the range of values of a random quantity when estimating the probability density. The criterion of efficiency is taken to be an asymptotic expression for the mean square deviation of a regression fit for the probability density. © 2015 Springer Science+Business Media New York

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Держатели документа:
Institute of Computational Modeling, Siberian Branch, Russian Academy of Sciences, Krasnoyarsk, Russian Federation
Siberian State Aerospace University, Krasnoyarsk, Russian Federation

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

[Текст] : статья / И. В. Киреев // Вычислительные технологии. - 2015. - Т. 20, № 2. - С. 44-55 . - ISSN 1560-7534
   Перевод заглавия: Inexpensive stopping criteria in the conjugate gradient method
Аннотация: Обсуждаются некоторые аспекты численной реализации метода сопряженных градиентов для решения систем линейных алгебраических уравнений с симметричной положительно определенной матрицей при наличии ошибок округления. Рассмотрены как пошаговое поведение некоторых широко распространенных версий алгоритма, так и критерии останова итерационного процесса.
In the paper, some aspects of the numerical implementation of the conjugate gradient method (CGM) for systems of linear algebraic equations with symmetric positive definite matrix in the presence of round-off errors are discussed. With exact calculations, CGM provides an exact solution in a finite number of iteration steps. But in fact CGM is an iterative process and the weak point in an iterative process is in a stopping criterion. It is required to determine the number of the iteration step, after which the accuracy of an approximation to a solution of a system of linear equations may not be considerably improved with a particular computer. Hence, the construction of inexpensive stopping criteria for CGM being the aim of this paper is an urgent problem. For four popular versions of CGM, the step-by-step behavior as well as stopping criteria for an iterative process are considered. Numerical results show that the most accurate approximation is achieved by the CGM-version where descent directions and residual vectors are orthogonal in the energy and Euclidean metrics, respectively, at each iteration step. A practical stopping criteria for CGM is proposed as a formula that enables one to determine the number of the CGM iteration step, starting with which the progress is no longer being made. The application of the constructed criteria to the solution of specific systems of linear algebraic equations with ill-conditioned matrices is demonstrated.

РИНЦ

Держатели документа:
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Kireev I.V.

[Текст] : статья / Е. А. Новиков // Вычислительные методы и программирование: новые вычислительные технологии. - 2015. - Т. 16, № 3. - С. 446-455 . - ISSN 1726-3522
   Перевод заглавия: A variable structure algorithm using the (3,2)-scheme and the Fehlberg method

УДК

519.622

Аннотация: Построен (3,2)-метод третьего порядка с замораживанием матрицы Якоби, в котором L-устойчивыми являются основная и промежуточные численные схемы. Получено неравенство для контроля точности вычислений с использованием вложенного метода второго порядка. Предложено неравенство для контроля устойчивости явного трехстадийного метода Рунге-Кутта-Фельберга третьего порядка. Сформулирован алгоритм переменной структуры, в котором на каждом шаге явный или L-устойчивый метод выбираются по критерию устойчивости. Приведены результаты расчетов.
A third-order (3,2)-method allowing freezing the Jacobi matrix is constructed. Its main and intermediate numerical schemes are L-stable. An accuracy control inequality is obtained using an embedded method of second order. A stability control inequality for the explicit three-stage Runge-Kutta-Fehlberg method of third order is proposed. A variable structure algorithm is formulated. An explicit or L-stable method is chosen according to the stability criterion at each step. Numerical results are discussed.

РИНЦ,
Полный текст

Держатели документа:
Институт вычислительного моделирования СО РАН

Доп.точки доступа:
Novikov E.A.

[Текст] : статья / А. В. Лапко, В. А. Лапко // Измерительная техника. - 2015. - № 5. - С. 10-14 . - ISSN 0368-1025

УДК

519.24

Аннотация: Предложена методика сравнения эффективности процедур дискретизации интервала значений случайной величины при оценивании плотности вероятности. В качестве критерия эффективности использовано асимптотическое выражение среднеквадратического отклонения регрессионной оценки плотности вероятности.
The comparison procedure for the effectiveness of methods for discretization of the interval of values of a random variable at probability density estimation has been saggested. As an efficiency criterion the asymptotic expression of standard deviation of regression model of probability density has been used.

РИНЦ

Держатели документа:
Институт вычислительного моделирования СО РАН
Сибирский государственный аэрокосмический университет им. акад. М. Ф. Решетнева

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

[Текст] : статья / Е. А. Новиков // Известия высших учебных заведений. Поволжский регион. Физико-математические науки. - 2015. - № 3. - С. 50-60 . - ISSN 2072-3040
   Перевод заглавия: Variable structure algorithm applying 3-stage methods of Runge-Kutta and Rosenbrock types

УДК

519.622

Аннотация: Актуальность и цели. Проблема решения задачи Коши для жестких систем большой размерности возникает при моделировании физических и химических процессов, при аппроксимации уравнений в частных производных системой обыкновенных дифференциальных уравнений и во многих других важных приложениях. Учет большого числа факторов при построении математических моделей приводит к расширению класса задач, описываемых жесткими системами большой размерности. Сложность практических задач приводит к возрастающим требованиям к вычислительным алгоритмам. Материалы и методы. В случае большой размерности жесткой системы дифференциальных уравнений основные затраты приходятся на декомпозицию матрицы Якоби. В некоторых алгоритмах применяется замораживание матрицы Якоби, т.е. одна матрица используется на нескольких шагах интегрирования. Проблема замораживания матрицы достаточно просто решается в методах, в которых стадии вычисляются с применением итерационного процесса. Для безытерационных численных формул это существенная проблема. В данной работе сокращение затрат достигается за счет комбинирования явных и L -устойчивых методов по критерию устойчивости в процессе расчетов. Результаты. Создан алгоритм интегрирования переменной структуры на основе явной схемы типа Рунге - Кутты и L -устойчивого метода типа Розенброка третьего порядка. На каждом шаге эффективная численная формула выбирается по критерию устойчивости. Оценка максимального собственного числа матрицы Якоби, необходимая для переключения между методами, для явных численных схем определяется степенным методом через ранее вычисленные стадии, а для метода типа Розенброка - через норму матрицы Якоби. Построены неравенства для контроля точности и устойчивости. Приведены результаты расчетов. Выводы. Алгоритм интегрирования предназначен для решения жестких задач большой размерности. Результаты расчетов подтверждают эффективность построенного алгоритма.
Background. The Cauchy problem for large-scale stiff systems arises in simulation of physical and chemical processes, in approximation of partial differential equations by a system of ordinary differential equations and in plenty of other important applications. Taking into consideration a large number of factors in model development leads to expansion of a class of problems, determined by stiff systems of high dimension. The complexity of practical problems leads to additional requirements to computational algorithms. Materials and methods. Dealing with high dimensionality of a stiff system of ordinary differential equations, the main computational expenses concern the Jacobi matrix decomposition. In some algorithms one may use freezing of the Jacobi matrix, i.e. applying the same matrix over several integration steps. The problem of freezing is solved rather easy in those methods, the stages of which are computed using some iterative processes. For non-iterative numerical formulas the freezing is quite a difficult problem. In this study, the costs reduction was achieved by combining explicit and L-stable methods using the criterion of stability in calculations. Results. The author has created an algorithm of variable structure integration, based on the explicit scheme of the Runge-Kutta type and the L-stable method of the Rosenbrock type. Both schemes have the third order of accuracy. An efficient numerical formula was chosen according to the criterion of stability at each step of integration. Estimation of maximum eigen value, which is necessary to switch between the methods, for explicit numerical schemes was determined by power iterations using already computed stages, and using the Jacobi matrix norm for the Rosenbrock type method. The researcher also formulated inequalities for accuracy and stability control. The article adduces the results of calculations. Conclusions. The integration algorithm is aimed at solving stiff problems of high dimension. Numerical results confirm the efficiency of the constructed algorithm.

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Держатели документа:
Институт вычислительного моделирования Сибирского отделения РАН

Доп.точки доступа:
Novikov E.A.

[Text] / V. M. Belolipetskii, P. V. Belolipetskii // J. Appl. Mech. Tech. Phys. - 2016. - Vol. 57, Is. 1. - P8-12, DOI 10.1134/S0021894416010028. - Cited References:4. - This work was supported by the Russian Foundation for Basic Research (Grant No. 14-01-00296). . - ISSN 0021-8944. - ISSN 1573-8620РУБ Mechanics + Physics, Applied

Аннотация: Wind flows in meromictic saline lakes in which the water column is not mixed to the bottom for at least one year are studied. This leads to the formation of upper and depth layers with small density gradients, between which there is a water layer with a large density gradient. It has been shown that, depending on the density stratification and the wind speed, wind flows (in the vertical plane) of two types are possible: with one or two circulation zones. For a two-layer lake model, a criterion for the change in the wind flow regime is proposed.

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Держатели документа:
Russian Acad Sci, Inst Computat Modeling, Siberian Branch, Krasnoyarsk 660036, Russia.
Siberian Fed Univ, Krasnoyarsk 660041, Russia.
Russian Acad Sci, Inst Biophys, Krasnoyarsk 660036, Russia.

Доп.точки доступа:
Belolipetskii, V. M.; Belolipetskii, P. V.; Russian Foundation for Basic Research [14-01-00296]

[Text] / A. V. Lapko, V. A. Lapko // Meas. Tech. - 2016. - Vol. 59, Is. 2. - P122-126, DOI 10.1007/s11018-016-0928-y. - Cited References:9 . - ISSN 0543-1972. - ISSN 1573-8906РУБ Engineering, Multidisciplinary + Instruments & Instrumentation

Аннотация: We investigate the asymptotic properties of nonparametric estimation of a two-dimensional probability density, whose synthesis involves the decomposition of statistical data. We determine the dependence of the number of two-dimensional sampling intervals on the volume of the original data.

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Держатели документа:
Russian Acad Sci IVM SO RAN, Inst Computat Modeling, Siberian Branch, Krasnoyarsk, Russia.
Siberian State Aerosp Univ, Krasnoyarsk, Russia.

Доп.точки доступа:
Lapko, A. V.; Lapko, V. A.

[Text] / I. V. Stepanova, A. A. Chesnokov, V. Y. Liapidevskii // ALL-RUSSIAN CONFERENCE ON NONLINEAR WAVES: THEORY AND NEW APPLICATIONS : IOP PUBLISHING LTD, 2016. - Vol. 722: All-Russian Conference on Nonlinear Waves - Theory and New Applications (FEB 29-MAR 02, 2016, Novosibirsk, RUSSIA). - Ст. UNSP 012036. - (Journal of Physics Conference Series), DOI 10.1088/1742-6596/722/1/012036. - Cited References:13 . - РУБ Physics, Applied + Physics, Multidisciplinary

Аннотация: In this paper we study the emergence and development of roll waves in two-layer fluid flow in a Hele-Shaw cell. We propose the mathematical model of such flow and define the conditions of transition from stable state to instability in the form of the roll waves. We find out the physical parameters of flows at which the roll waves exist. A linear stability analysis and the Whitham criterion of roll waves existence are used for solving the problem and arrive to identical conclusions on depths of upper and lower layers at which violation of flow stability occurs. The numerical calculations for the obtained mathematical model at found ratios of densities, viscosities and depths of layers are performed. They confirm development of the roll waves of finite amplitude from small oscillations of the interface.

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Держатели документа:
Novosibirsk State Univ, Novosibirsk, Russia.
Inst Computat Modelling SB RAS, Krasnoyarsk, Russia.
Lavrentyev Inst Hydrodynam SB RAS, Novosibirsk, Russia.

Доп.точки доступа:
Stepanova, I. V.; Chesnokov, A. A.; Liapidevskii, V. Yu

[Текст] : статья / А. В. ЛАПКО, В. А. ЛАПКО // Измерительная техника. - 2016. - № 2. - С. 14-17 . - ISSN 0368-1025

УДК

519.24

Аннотация: Исследованы асимптотические свойства непараметрической оценки двухмерной плотности вероятности, синтез которой предполагает декомпозицию статистических данных. Определена зависимость количества двухмерных интервалов дискретизации от объема исходной информации.
The asymptotic properties of nonparametric estimation of two-dimensional probability density have been studied. The synthesis of this estimation presupposes decomposition of statistical data. The dependence is determined of the number of two-dimensional sampling intervals on the volume of the original data.

РИНЦ

Держатели документа:
Институт вычислительного моделирования СО РАН
Сибирский государственный аэрокосмический университет им. акад. М.Ф. Решетнева

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