Journal Issue: Научная визуализация
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Volume
15
Number
3
Issue Date
Journal Title
Journal ISSN
2079-3537
Том журнала
Том журнала
Научная визуализация
(15)
Статьи
Публикация
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Visualization of the Evolution of a Single Vapor Bubble During Boiling of a Subcooled Liquid: Experience in Automating the Processing of High-Speed Video Recording Results
(2023) Vasil’ev, N. V. ; Vavilov, S. N. ; Zeigarnik, Yu. A. ; Azarov, N. A.
Subcooled liquid boiling makes it possible to remove extremely high heat flux densities (tens, and under certain conditions even hundreds of MW/m2). This method is used for cooling rocket nozzles, in metallurgy, in thermonuclear power and special installations (cooling of beam targets), pulsed magnetohydrodynamic (MHD) installations. However, the calculations of this process are based on purely empirical correlations. The lack of experimental data on the characteristics of bubbles (size evolution, life time, formation frequency) hinders the development of mathematical models and calculation methods.
The paper presents a program developed in the Python 3.10 environment for automated processing of high-speed video recordings of the evolution of a single bubble during boiling of a subcooled liquid. Comparison of frame processing, carried out «manually» and with the help of the developed program, showed a fairly high agreement between the results. The developed method makes it possible to significantly reduce the time spent on processing the experimental material and to include a significantly larger array of experimental data in the analysis.
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Hybrid Visualization with Vulkan-OpenGL: Technology and Methods of Implementation in Virtual Environment Systems
(2023) Timokhin, P. Yu. ; Mikhaylyuk, M. V.
In this paper, the topic of integrating visualization tasks to be solved using the Vulkan API into virtual environment systems based on OpenGL visualization, is researched. The problem of Vulkan-OpenGL hybrid visualization and an approach to its solution, based on a modified render-to-texture technique, are described. The technology of constructing an original embeddable program shell (VK-capsule) is proposed, which allows hybrid visualization as a "black box" to be worked with, obtaining an image in the OpenGL frame buffer at the output. The paper presents the developed structure of the VK-capsule, comprising three program blocks (VK-, GL- and I-block), and describes methods and algorithms for their construction. Based on proposed technology, methods and algorithms, a VK-capsule for height field visualization task was developed, which utilizes hardware-accelerated ray tracing, Vulkan API supported by. The approbation of the developed VK-capsule was carried out, which showed that proposed solutions are effective and meet the task. The results obtained can be used in virtual environment systems, scientific visualization, video simulators, virtual laboratories, educational applications, etc.
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Universal System for Visualizing Geo-Referenced Data - Speed Vector Data
(2023) Voronina, N. N. ; Zapevalov, A. S.
In 2016, an article [1] was published in the Scientific Visualization No. 1 journal, which marked the beginning of a series of publications, in one way or another related to the visualization of georeferenced data. In 2023, an article [2] was published in the journal Scientific Visualization, which continued this series. This article describes step by step the process of developing and debugging a software product for visualizing geophysical data with their subsequent layout on a Yandex satellite map. The initial information for building maps was a text file containing three columns of data: two columns are geographic coordinates, the third column is a scalar parameter, such as temperature or salinity. The presented work is a direct continuation of this series. It describes the procedure for visualizing vector geophysical parameters on the Yandex satellite map, for example, such as current velocity or wind speed. The visualization procedure for vector parameters is based on a similar procedure previously developed for scalar parameters. The paper describes in detail the process of developing and debugging, modifying a software product, the ultimate goal of which is to visualize only the geophysical velocity parameter with subsequent display on the Yandex satellite map in accordance with the geographic coordinates that are set as input. The software product is a fully debugged complete module that can work both in standalone mode and in a complex aimed at superimposing the result obtained on the Yandex satellite map.
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Liquid Crystal Visualization in The Study of the Flow in a Shallow Cavity
(2023) Zharkova, G. M ; Kovrizhina, V. N. ; Mironov, D. S. ; Pak, A. Yu. ; Petrov, A. P.
Using the example of a flow around a shallow cavity, the possibilities of liquid-crystal visualization at subsonic and supersonic flow velocities are demonstrated. To determine the flow structure at the bottom of the cavity, a coating based on a composition of pure cholesteric liquid crystals (ChLC) was used. To determine the distribution of temperatures and heat fluxes, thermosensitive films formed by encapsulation of ChLC in a polymer matrix were used.
Based on the experimental results, the influence of the Mach number on the spatial pattern of the flow inside the cavity and the temperature distribution at the bottom of the cavity was obtained. The pattern of surface streamlines obtained by the LC coating coincides with that obtained using the oil film visualization. In this case, the LC method makes it possible to compare the values of shear stresses in different parts of the surface also. It is found that the occurrence of resonance phenomena leads to restructuring of the flow inside the cavity and a change in the values of shear stresses. It is shown, that in subsonic flow around the zone of increased heat transfer is concentrated near the axis of symmetry of the cavity.
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High-Speed Flow Visualization by a Nanosecond Volume Discharge during Shock Wave Diffraction on an Obstacle
(2023) Mursenkova, I. ; Ivanova, A.; Ivanov, I.; Sysoev, N. ; Karimov, A.
We study the spatial structure of nonstationary inhomogeneous supersonic airflows as shock wave diffraction on an obstacle occurs in a shock tube of a rectangular cross section. The Mach numbers of shock waves were 2.7–4.4 at initial air pressures of 10–30 Torr. The supersonic flow in the discharge chamber was visualized by high-speed shadowgraphy and by the registration of radiation of combined volume discharge by photo camera and by ICCD camera. In experiments, a combined volume discharge with a current duration of ~ 500 ns was initiated 40–150 μs after the initial shock wave have passed an obstacle. It has been established that the radiation of the volume phase of discharge lasts 400–700 ns, and the displacement of the flow during this time does not exceed 0.6 mm. A correlation is established between the spatial distribution of discharge radiation and the low-density local areas determined as a result of two-dimensional Navier-Stokes based numerical simulation of the flow. As visualized by the glow of the discharge, the shape of the shock wave front is in good agreement with the results of shadowgraphy at different stages of diffraction and with the numerical simulation results.