Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva最新文献_第8页

Asymptotic study of heat and mass transfer in weakly twisted jets 弱扭曲射流中传热传质的渐近研究

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2020-06-30 DOI: 10.15507/2079-6900.22.202002.200-207

P. A. Velmisov, Usama J. Mizher, V. Kovalnogov

{"title":"Asymptotic study of heat and mass transfer in weakly twisted jets","authors":"P. A. Velmisov, Usama J. Mizher, V. Kovalnogov","doi":"10.15507/2079-6900.22.202002.200-207","DOIUrl":"https://doi.org/10.15507/2079-6900.22.202002.200-207","url":null,"abstract":"Jet flows of liquids and gases are used in various fields of technology as means of controlling the processes of heat and mass transfer, for the intensification and stabilization of the combustion process, as means of protecting structures from exposure to thermal fields, for coating, etc. The jets of liquids and gases in technology are formed by sources-nozzles of finite sizes with various distributions of the initial outflow velocities in the outlet section of the nozzle, therefore, the calculation of the aerodynamic and thermal characteristics of jet flows is reduced to solving non-self-similar problems. However, one of the methods for solving such problems is the method of asymptotic expansion of velocities and pressure in series in a small parameter, when the first member of this series is a self-similar solution to the jet source problem. This article proposes an asymptotic expansion for axisymmetric weakly swirling flows in a model of a viscous incompressible medium, which leads to nonlinear «boundary layer» equations that differ from the well-known classical equations [1]–[4] for flows with finite swirl. Self-similar solutions of these equations are constructed that describe the distribution of speed, pressure, and temperature in a weakly swirling jet. The results presented in the article complement the results of [3]–[7] by calculating the thermal field in the jet.","PeriodicalId":273445,"journal":{"name":"Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133452824","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

About one method for replacing variables for a wavean equation describing vibrations of systems with moving boundaries 描述具有移动边界的系统振动的波方程的一种变量替换方法

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2020-06-30 DOI: 10.15507/2079-6900.22.202002.188-199

V. N. Anisimov, V. Litvinov

引用次数: 0

On the disposition of cubic and pair of conics in a real projective plane 实数投影平面上三次曲线和二次曲线的处理

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2020-03-31 DOI: 10.15507/2079-6900.22.202001.24-37

V. A. Gorskaya, G. M. Polotovskiy

引用次数: 0

On a nonlocal boundary value problem with an oblique derivative 具有斜导数的非局部边值问题

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2020-03-31 DOI: 10.15507/2079-6900.22.202001.81-93

K. Nazarova, B. Turmetov, K. Usmanov

{"title":"On a nonlocal boundary value problem with an oblique derivative","authors":"K. Nazarova, B. Turmetov, K. Usmanov","doi":"10.15507/2079-6900.22.202001.81-93","DOIUrl":"https://doi.org/10.15507/2079-6900.22.202001.81-93","url":null,"abstract":"The work studies the solvability of a nonlocal boundary value problem for the Laplace equation. The nonlocal condition is introduced using transformations in the Rn space carried out by some orthogonal matrices. Examples and properties of such matrices are given. To study the main problem, an auxiliary nonlocal Dirichlet-type problem for the Laplace equation is first solved. This problem is reduced to a vector equation whose elements are the solutions of the classical Dirichlet probem. Under certain conditions for the boundary condition coefficients, theorems on uniqueness and existence of a solution to a problem of Dirichlet type are proved. For this solution an integral representation is also obtained, which is a generalization of the classical Poisson integral. Further, the main problem is reduced to solving a non-local Dirichlet-type problem. Theorems on existence and uniqueness of a solution to the problem under consideration are proved. Using well-known statements about solutions of a boundary value problem with an oblique derivative for the classical Laplace equation, exact orders of smoothness of a problem's solution are found. Examples are also given of the cases where the theorem conditions are not fulfilled. In these cases the solution is not unique.","PeriodicalId":273445,"journal":{"name":"Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129140778","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

Combinatorial invariant of Morse-Smale diffeomorphisms on surfaces with orientable heteroclinic 可定向异斜曲面上morse - small微分同态的组合不变量

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2020-03-31 DOI: 10.15507/2079-6900.22.202001.71-80

A. Morozov, O. Pochinka

引用次数: 1

The discrete continuation in the boundary value problem for systems of nonlinear differential equations with deviation argument 具有偏差参数的非线性微分方程组边值问题的离散延拓

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2019-09-30 DOI: 10.15507/2079-6900.21.201903.309-316

M. N. Afanaseva, E. Kuznetsov

引用次数: 0

On an iterative process for the grid conjugation problem with iterations on the boundary of the solution discontinuity 关于网格共轭问题的迭代过程，迭代解的边界为不连续点

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2019-09-30 DOI: 10.15507/2079-6900.21.201903.329-342

F. Lubyshev, M. E. Fairuzov

{"title":"On an iterative process for the grid conjugation problem with iterations on the boundary of the solution discontinuity","authors":"F. Lubyshev, M. E. Fairuzov","doi":"10.15507/2079-6900.21.201903.329-342","DOIUrl":"https://doi.org/10.15507/2079-6900.21.201903.329-342","url":null,"abstract":"An iterative process for the grid problem of conjugation with iterations on the boundary of the discontinuity of the solution is considered. Similar grid problem arises in difference approximation of optimal control problems for semilinear elliptic equations with discontinuous coefficients and solutions. The study of iterative processes for the states of such problems is of independent interest for theory and practice. The paper shows that the numerical solution of boundary problems of this type can be efficiently implemented using iterations on the inner boundary of the grid solution discontinuity in combination with other iterative methods for nonlinearities separately in each of the grid subregions. It can be noted that problems for states of controlled processes described by equations of mathematical physics with discontinuous coefficients and solutions arise in mathematical modeling and optimization of heat transfer, diffusion, filtration, elasticity theory, etc. The proposed iterative process reduces the solution of the initial grid boundary problem for a state with a discontinuous solution to a solution of two special boundary problems in two grid subdomains at every fixed iteration. The convergence of the iteration process in the Sobolev grid norms to the unique solution of the grid problem for each initial approximation is proved.","PeriodicalId":273445,"journal":{"name":"Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133225467","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

Mathematical modeling of the magnetic properties of spheroids of hard second kind superconductors in the Bean model 硬第二类超导体椭球体在Bean模型中的磁性数学建模

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2019-09-30 DOI: 10.15507/2079-6900.21.201903.353-362

N. D. Kuzmichev, A. A. Shushpanov, M. A. Vasyutin

引用次数: 0

Strength analysis of composite rotor helicopter blade, having percussive damage, by limit equilibrium theory 基于极限平衡理论的复合旋翼直升机叶片冲击损伤强度分析

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2019-09-30 DOI: 10.15507/2079-6900.21.201903.343-352

I. Sidorov, V. I. Mitryaikin, A. Gorelov, L. P. Shabalin

{"title":"Strength analysis of composite rotor helicopter blade, having percussive damage, by limit equilibrium theory","authors":"I. Sidorov, V. I. Mitryaikin, A. Gorelov, L. P. Shabalin","doi":"10.15507/2079-6900.21.201903.343-352","DOIUrl":"https://doi.org/10.15507/2079-6900.21.201903.343-352","url":null,"abstract":"Authors model the limiting state of the helicopter «ANSAT» rotor blade at different flight modes, taking into account the possible damage to the blade in the butt section. The method of variation of elastic constants, based on the limit equilibrium theory and allowing to obtain both upper and lower limits of the limit load, is used to estimate the strength. The stresses in the layers determined in accordance with the deformation law of the associated limit yield surface of these layers, are expressed in terms of the six-dimensional vector of generalized forces. Analysis of the limit stress state is reduced to the analysis of the limit state in the space of the generalized forces. The safety factors of the blade’s butt section depending on the azimuth angle of rotation of the blade are determined for the case when all the generalized forces are proportional to one loading parameter. The possibility of making internal diagnostics of damage areas using x-ray computer tomography is announced. It is proposed to use medical Siemens x-ray tomograph to perform such diagnostics.","PeriodicalId":273445,"journal":{"name":"Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123735204","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 influence of light intensity on the limits of applicability of modulated optical signals recovery method 光强对调制光信号恢复方法适用范围的影响

Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva Pub Date : 2019-09-30 DOI: 10.15507/2079-6900.21.201903.363-371

E. V. Nikishin, V. Y. Grishaev, S. M. Muryumin

{"title":"On the influence of light intensity on the limits of applicability of modulated optical signals recovery method","authors":"E. V. Nikishin, V. Y. Grishaev, S. M. Muryumin","doi":"10.15507/2079-6900.21.201903.363-371","DOIUrl":"https://doi.org/10.15507/2079-6900.21.201903.363-371","url":null,"abstract":"The kinetics of silicon photoconductivity with recombination centers of gold is investigated. If the frequency of light intensity modulation is less than the inverse value of the main charge carriers’ lifetime, the functions describing the dependence of light intensity on time and the dependence of the photocurrent on time agree within some factor. At high frequencies of modulation of light intensity distortions arise. The dependences of light intensity on time and photocurrent on time become different. In this case, the effect of the recombination rate on the function of the variable component of the photocurrent is not significant. Basically, this function is determined by the dependence of the generation rate on time. At high frequencies, it is possible to \"restore\" the shape of the optical pulse using the electric pulse of the photoresistor. The dependences on the frequency of phase, linear and nonlinear distortions arising in the \"restoration\" of the dependence of the light intensity on time are obtained. The results are given for different values of the rate of charge carrier generation.","PeriodicalId":273445,"journal":{"name":"Zhurnal Srednevolzhskogo Matematicheskogo Obshchestva","volume":"15 5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128673689","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