Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics最新文献_第4页

Numerical simulation of turbulent flows on the basis of a two-fluid model of turbulence 基于双流体湍流模型的湍流数值模拟

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/82/10

M. Madaliev

引用次数: 0

Ablation of small meteor bodies: comparison of solid and porous body models 小流星的消融:固体和多孔体模型的比较

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/81/10

V. Efremov, O. Popova, D. Glazachev, A. Margonis, J. Oberst, A. Kartashova

{"title":"Ablation of small meteor bodies: comparison of solid and porous body models","authors":"V. Efremov, O. Popova, D. Glazachev, A. Margonis, J. Oberst, A. Kartashova","doi":"10.17223/19988621/81/10","DOIUrl":"https://doi.org/10.17223/19988621/81/10","url":null,"abstract":"An ablation model is used to describe the interaction of small meteoroids with the Earth’s atmosphere. In this model, the mass loss of a meteoroid is determined using the saturated vapor pressure of the assumed meteoroid substance. The meteoroid is considered in two modifications as a solid and a porous object. An automated method for estimating the parameters of meteoroids (mass, size, and density) from light curves is developed based on the model of small meteor body ablation, which has been used to estimate the parameters of the Perseid meteors with a brightness of -2m to +2m. The effect of the dependence for saturated vapor pressure and the residual on the parameters of the meteoric body is analyzed. It is shown that for the same meteor, the use of different dependences for pressure or different residuals leads to the dispersion of the meteor mass estimate of not more than 10-15% of the average value, and for the meteor size not more than 35-40%. The difference between the maximum and minimum density estimates can be up to five times. The selected dependence for the saturation vapor pressure strongly affects the shape of the light curve, the quality of its approximation, and the density estimate. The average porosity for all meteoroids is 86±5%, which is close to the values for IDP. The density of meteoroids is determined with a large error. The selected model better describes meteoroids with the degree of skewness of the light curve in the range of 0.4 - 0.5. The use of the porous body model has little effect on the mass estimate, while the density estimates increase by up to 2 times.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"50 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88919449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

On the principle of least action in terms of incompressible fluid flow in a channel of variable cross-section 变截面通道中不可压缩流体流动的最小作用原理

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/81/7

G. I. Afonin

引用次数: 0

Localized eigenfunctions in the asymptotic model of the spectral problem 谱问题渐近模型中的局域特征函数

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/82/1

Evgeniya. A. Molchanova

引用次数: 0

Finite groups with permuted strongly generalized maximal subgroups 具有置换强广义极大子群的有限群

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/80/3

Yulia V. Gorbatova

引用次数: 0

Experimental and theoretical studies of the flow around a sphere with account for gas injection from its surface 考虑气体从球体表面喷射的情况下绕球体流动的实验和理论研究

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/81/6

V. Arkhipov, S. Basalaev, K. Kostyushin, K. G. Perfil′eva, A. Usanina

{"title":"Experimental and theoretical studies of the flow around a sphere with account for gas injection from its surface","authors":"V. Arkhipov, S. Basalaev, K. Kostyushin, K. G. Perfil′eva, A. Usanina","doi":"10.17223/19988621/81/6","DOIUrl":"https://doi.org/10.17223/19988621/81/6","url":null,"abstract":"The results of the experimental and theoretical studies of the gas flow around a solid sphere under conditions of mass outflow from its surface are presented. A new experimental setup and a method for studying the flow around a solid sphere during the gas injection from its surface are proposed with the aim of improving the accuracy of determining the drag coefficient. In the range of the Reynolds number (Re = 133÷667), experimental results show that the drag coefficient decreases at the gas injection from the surface of the sphere. Moreover, the drag coefficient decreases with an increase in the density of the injected air flow at the fixed Reynolds number. Numerical simulation of a two-phase flow around a sphere with the gas injection from its surface is carried out for two calculation cases: with a uniform gas outflow from the surface of a porous sphere and with gas injection from perforated holes on the sphere surface. The numerical calculation results for the case of gas injection from the holes of the sphere are in quantitative and qualitative agreement with the experimental data.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"40 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80871986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Simulation of the interaction of conical impactors having an angle of attack with underwater barriers 具有攻角的锥形冲击体与水下障碍物相互作用的模拟

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/80/4

S. Batuev, A. S. D’yachkovskiy, P. Radchenko, A. Radchenko, A. Sammel’, Andrey V. Chupashev

{"title":"Simulation of the interaction of conical impactors having an angle of attack with underwater barriers","authors":"S. Batuev, A. S. D’yachkovskiy, P. Radchenko, A. Radchenko, A. Sammel’, Andrey V. Chupashev","doi":"10.17223/19988621/80/4","DOIUrl":"https://doi.org/10.17223/19988621/80/4","url":null,"abstract":"In this paper, the effect of the angle of impact and the angle of attack on the interaction between truncated coneshaped impactors made of BHZh-95 alloy and underwater barriers made of aluminum alloy is studied using experimental and computational methods. When such an impactor enters water, a supercavern appears around the impactor and minimizes the fluid friction. During the motion, the impactor afterbody periodically experiences impermanent contact with the walls of the supercavern, which maintains the steady motion. Note that the center of mass of the impactor is located closer to its afterbody, which can induce the angle of attack appearance during the motion. The experimental study is conducted using a hydroballistic track with high-speed video recording. The speed range of 250-350 m/s is considered. Mathematical modeling is carried out using the EFES original software package. It is revealed that a positive angle of attack β ≤ 10° leads to the normalization of the impactor and a decrease in the effective thickness of the barrier with its perforation. In contrast, at a negative angle of attack, the impactor rebounds from the barrier.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"147 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81857550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Response of fine-grained fiber-reinforced concrete under different mechanical loading conditions 细粒纤维增强混凝土在不同受力条件下的响应

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/81/9

D. Lamzin, M. E. Gonov, A. Bragov, A. Lomunov

{"title":"Response of fine-grained fiber-reinforced concrete under different mechanical loading conditions","authors":"D. Lamzin, M. E. Gonov, A. Bragov, A. Lomunov","doi":"10.17223/19988621/81/9","DOIUrl":"https://doi.org/10.17223/19988621/81/9","url":null,"abstract":"This paper presents an experimental study of the deformation and energy absorption of fiber-reinforced concretes under compression at different strain rates. Static load tests are carried out using the Zwick-Roell Z100 universal testing machine at a strain rate of 30*10\"6 s-1. Dynamic load tests are carried out in the range of strain rates 200-800 s-1 using the Kolsky method, which implies loading of the studied sample in a split Hopkinson pressure bar system. Specimens are made from a concrete mixture with the addition of wavy steel or polypropylene fibers with a volume fraction of 1.5 %. As a result of experiments and processing of the recorded strain pulses of measuring bars, the deformation diagrams and the corresponding diagrams of the specific energy absorption for the fiber-reinforced concretes under study are constructed. For all concretes being studied, the diagrams of deformation and energy absorption have similar trends and show an increase in the strength and energy before fracture initiation with an increase in the strain rate.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"125 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90608708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Periodic combustion regimes for thermally coupled SHS systems with a thermocapillary melt flow 具有热毛细熔体流动的热耦合SHS系统的周期性燃烧机制

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2023-01-01 DOI: 10.17223/19988621/80/10

V. Prokof'ev

{"title":"Periodic combustion regimes for thermally coupled SHS systems with a thermocapillary melt flow","authors":"V. Prokof'ev","doi":"10.17223/19988621/80/10","DOIUrl":"https://doi.org/10.17223/19988621/80/10","url":null,"abstract":"This paper presents a three-dimensional mathematical model of self-propagating high-temperature synthesis (SHS) of a three-layer “sandwich” sample. The layers are formed from gasless mixtures with the addition of an inert fusible component. The mathematical model is studied numerically using the finite-difference method. The unsteady periodic regimes of gasless combustion of the three-layer sample with square cross-section are revealed with account for melting and thermocapillary flow of the melted inert component of the mixture. The unsteady periodic combustion regimes are specified depending on the relative calorific value of the mixture in the inner layer. High-temperature points move along the side faces of the sample. The velocity of the points’ motion along the combustion surface is much higher than the average burning velocity of the sample. An increase in the melt flow velocity leads to the equalization of the temperature field and stabilization of the combustion regime. The quasi-stationary regimes of control and fusion are studied during the combustion of the sample with an active inner layer, when the intrinsic burning velocities of the donor and acceptor mixtures are close to each other.","PeriodicalId":43729,"journal":{"name":"Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics","volume":"56 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90637682","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

ОСОБЕННОСТИ РАСПРОСТРАНЕНИЯ ПЛАМЕНИ В УГЛЕ-ПРОПАНО-ВОЗДУШНОЙ ГАЗОВЗВЕСИ 丙烷气体燃煤燃烧特性

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Vestnik Tomskogo Gosudarstvennogo Universiteta-Matematika i Mekhanika-Tomsk State University Journal of Mathematics and Mechanics Pub Date : 2022-09-28 DOI: 10.17223/19988621/74/10

А. К. Кантарбаева, Ксения Михайловна Моисеева

引用次数: 0