849 research outputs found
RETRACTED: Forecasting the development dynamics of coastal systems utilizing remote sensing data
No full textSee the retraction notice E3S Web of Conferences 549, 00001 (2024), https://doi.org/10.1051/e3sconf/20245490000
Turbulent plane Couette flow with wall-transpiration
No full textIn the present abstract, DNS results obtained for turbulent plane Couette flow with wall-normal transpiration velocity are presented. Important equations valid in such a flow are derived, describing the total shear stress and the relation between the friction velocities at the lower and upper wall. These expressions are of importance, as there are neither experimental nor DNS data to compare with. Equally important, we derive a center region and a viscous sublayer velocity scaling for the suction wall, which were both validated using the DNS data
Field data filtering for the digital simulation of three-dimensional turbulent flows using the LES approach
No full textСухинов Александр Иванович – член-корреспондент РАН, доктор физико-математических наук, профессор, заведующий кафедрой математики и информатики, Донской государственный технический университет, e-mail: [email protected].
Проценко Софья Владимировна – кандидат физико-математических наук, доцент кафедры математики, Таганрогский институт имени А.П. Чехова (филиал) Ростовского государственного экономического университета (РИНХ), e-mail: [email protected].
Проценко Елена Анатольевна – кандидат физико-математических наук, доцент кафедры математики, Таганрогский институт имени А.П. Чехова (филиал) Ростовского государственного экономического университета (РИНХ), e-mail: [email protected]. Sukhinov Aleksandr Ivanovich is Corresponding Member of the Russian Academy of Sciences, Doctor of Physical and Mathematical Sciences, Professor, Head of the Mathematics and Computer Sci-ence Department, Don State Technical University, Rostov-on-Don, Russian Federation, e-mail: [email protected], ORCID iD: https://orcid.org/0000-0002-5875-1523
Protsenko Sofya Vladimirovna is Candidate of Physical and Mathematical Sciences, Associate Professor of the Mathematics Department, Chekhov Taganrog Institute (branch) Rostov State University of Economics, Taganrog, Russian Federation, e-mail: [email protected], ORCID iD: https://orcid.org/0000-0001-9656-8466X
Protsenko Elena Anatol'evna is Candidate of Physical and Mathematical Sciences, Associate Professor of the Mathematics Department, Chekhov Taganrog Institute (branch) Rostov State University of Economics, Taganrog, Russian Federation, e-mail: [email protected], ORCID iD: https://orcid.org/0000-0001-7911-3558XТурбулентность и последующее перемешивание являются важными механизмами, определяющими динамику прибрежной зоны, перенос импульса, массы и тепла. В работе мелкомасштабное движение исключается из уравнений Навье-Стокса при помощи применения операции фильтрации и моделируется с использованием подсеточных моделей. Для этого в двумерном и трехмерном случаях применены различные виды фильтров: коробочный фильтр, фильтр Гаусса и фильтр Фурье, с постепенным уменьшением ширины фильтра, что позволяет воспроизвести более широкий частотный диапазон флуктуаций решения. Процедуре фильтрации подвержены натурные данные, полученные в ходе экспедиции в Центрально-Восточной части Азовского моря и в Таганрогском заливе на НИС «Денеб» Южного научного центра РАН. Для измерения трехмерного вектора скорости движения водной среды использовался гидрофизический ADCP-зонд Workhorse Sentinel 600, с помощью которого получено более 3 000 000 исходных измерений, в каждой точке (на каждой станции, которых 17) – более 150 000. Полученные данные планируется использовать для численного моделирования трехмерных турбулентных течений с применением подхода LES и сопоставления с результатами осреднения по RANS. В статье рассмотрены возможности применения различных типов аппроксимаций для параметризации вертикального турбулентного обмена. Проведено сравнение алгебраических моделей расчета коэффициента вертикального турбулентного обмена и полуэмпирических моделей турбулентности. Turbulence and subsequent mixing are important mechanisms which determine the dy-namics of the coastal zone, as well as the transfer of momentum, mass and heat. In this paper, small-scale motion is excluded from the Navier–Stokes equations by applying the filtering operation. It is then modeled using subgrid models. In two-dimensional and three-dimensional cases, various types of filters are used: a box filter, a Gaussian filter and a Fourier filter, with a gradual decrease in the filter width. This enables the reproduction of a wider frequency range of fluctuations of the solution. The natural data obtained during the expedition in the Central-Eastern part of the Sea of Azov and in the Taganrog Bay at the research vessel Deneb of the Southern Scientific Center of the Russian Academy of Sciences were subjected to the filtration procedure. The hydrophysical ADCP probe Workhorse Sentinel 600 was used to measure the three-dimensional velocity vector of the water medium. In this way more than 3,000,000 initial measurements were obtained, at each of the 17 stations more than 150,000 were taken. The data thus obtained will be used for the digital simulation of three-dimensional turbulent flows using the LES approach and comparison with the results of averaging by RANS.Исследование выполнено за счет гранта Российского научного фонда № 22-71-00015, https://rscf.ru/project/22-71-00015/
Correction to " Saint-Santin Radar Observations of Lower Thermospheric Storms"
No full textInternational audienceIn the paper "Saint-Santin Radar Observations of Lower Thermospheric Storms" by C. Mazaudier, R. Bernard and S.V. Venkateswaran (Journal of Geophysical Research 90 (A3), 2885-2895) the name of the third author was inadvertently omitted from the first page. A corrected first page follow
The peculiarities of aperture field distribution of reflector antenna with arbitrary positioned irradiator
No full textImproved parametrization of the vertical turbulent exchange coefficient, taking into account the shallow water bodies specifics
No full textThe article is devoted to the problem of improving the parameterization of the coefficient of turbulent exchange in shallow water bodies with significant depth differences and intensive vertical mixing. The article presents the basic equations of the model of taking into account the wave effect on the inhomogeneous vertical coefficient of turbulent exchange. This model is integrated into the system of Navier-Stokes equations taking into account the variable density, temperature and salinity, which describes the movement of a liquid under the influence of various forces, including pressure and viscosity, as well as forces caused by the action of waves. The article presents the discretization of the Navier-Stokes equations and the transfer equations by the finite difference method in three measurement directions. The additional term describing the wave effect on the vertical velocity in a shallow-water reservoir depends on the characteristics of the wave field: amplitude, angular frequency, wave number and coordinates. Using a model that takes into account the wave effect in three measuring directions and inhomogeneous turbulent exchange in the vertical direction, detailed information about the dynamics of waves in the simulated section of a shallow reservoir was obtained. The forecast of changes in hydrodynamic wave processes of the coastal zone is constructed. Inhomogeneous vertical turbulent exchange can vary significantly in different parts of a shallow reservoir and affect wave activity. Taking into account these changes makes the model more accurate and relevant to real conditions
Procedure of Computation of Local Phase Center Position and Analysis of Its Displacement for Antennas with Elliptical Polarization Radiation
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