Pub Date : 2021-02-01DOI: 10.17516/1997-1397-2021-14-1-87-97
K. Zavyalova, K. Shishmarev, A. Korobkin, Кристина Николаевна Завьялова, Константин Александрович Шишмарев, Александр А. Коробкин
The response of a poroelastic ice cover to an external load is considered. The ice cover is modeled by a thin poroelastic floating plate within the linear theory of hydroelasticity. The porosity parameter is defined as the coefficient of proportionality of the velocity of liquid penetration into the plate and hydrodynamic pressure. The fluid under the plate is inviscid and incompressible. The flow caused by the ice deflection is potential. The external load is modeled by a localized smooth pressure. The two-dimensional problem of waves caused by a periodic external pressure on a floating porous-elastic plate is considered. The profiles of the generated waves are calculated for a given oscillation frequency of the amplitude of the external pressure. It was found that taking porosity into account leads to damping of oscillations in a distance from the external load
{"title":"The Response of a Poroelastic Ice Plate to an External Pressure","authors":"K. Zavyalova, K. Shishmarev, A. Korobkin, Кристина Николаевна Завьялова, Константин Александрович Шишмарев, Александр А. Коробкин","doi":"10.17516/1997-1397-2021-14-1-87-97","DOIUrl":"https://doi.org/10.17516/1997-1397-2021-14-1-87-97","url":null,"abstract":"The response of a poroelastic ice cover to an external load is considered. The ice cover is modeled by a thin poroelastic floating plate within the linear theory of hydroelasticity. The porosity parameter is defined as the coefficient of proportionality of the velocity of liquid penetration into the plate and hydrodynamic pressure. The fluid under the plate is inviscid and incompressible. The flow caused by the ice deflection is potential. The external load is modeled by a localized smooth pressure. The two-dimensional problem of waves caused by a periodic external pressure on a floating porous-elastic plate is considered. The profiles of the generated waves are calculated for a given oscillation frequency of the amplitude of the external pressure. It was found that taking porosity into account leads to damping of oscillations in a distance from the external load","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"61 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77548249","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}
Pub Date : 2021-01-01DOI: 10.25205/2541-9447-2021-16-1-81-90
A. Yatskikh, A. Panina, V. Kocharin, Y. Yermolaev, A. Kosinov, N. Semionov
The results of experimental studies on the impact of periodic flow modulation on the development of natural disturbances and artificial localized wave packets in the boundary layer of a swept wing with a leading edge swept angle of 40 degrees at a Mach number M = 2.5 are presented. The boundary layer was modulated using periodic roughness on the model surface. Artificial wave packets were generated by a pulsed glow discharge. Hot-wire anemometer measurements showed that, according to the experimental conditions, periodic modulation of the boundary layer leads to the stabilization of the development of controlled localized disturbances and to an increase in the growth of natural disturbances.
{"title":"Experimental Studies of the Impact of Periodic Modulation of the Flow on the De-velopment of Disturbances in the Boundary Layer of a Swept Wing at a M = 2.5","authors":"A. Yatskikh, A. Panina, V. Kocharin, Y. Yermolaev, A. Kosinov, N. Semionov","doi":"10.25205/2541-9447-2021-16-1-81-90","DOIUrl":"https://doi.org/10.25205/2541-9447-2021-16-1-81-90","url":null,"abstract":"The results of experimental studies on the impact of periodic flow modulation on the development of natural disturbances and artificial localized wave packets in the boundary layer of a swept wing with a leading edge swept angle of 40 degrees at a Mach number M = 2.5 are presented. The boundary layer was modulated using periodic roughness on the model surface. Artificial wave packets were generated by a pulsed glow discharge. Hot-wire anemometer measurements showed that, according to the experimental conditions, periodic modulation of the boundary layer leads to the stabilization of the development of controlled localized disturbances and to an increase in the growth of natural disturbances.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"41 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78095783","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}
Pub Date : 2021-01-01DOI: 10.25205/2541-9447-2021-16-1-53-64
Yulia I. Usynina, Y. Yermolaev, A. Kosinov, N. Semionov
This paper presents the results of studying the features of the development of weak shock waves generated by a twodimensional roughness on the wall of the working part of a supersonic wind tunnel in a free flow at a Mach number of 2.5. The measurements were performed with a constant resistance thermoanemometer. It is shown that a twodimensional sticker induces weak shock waves into the free flow. They cause distortion of the average flow, the shape of which corresponds to the N-wave. High-intensity pulsations were recorded in the region of passage of a pair of weak shock waves. With an increase in the unit Reynolds number, the level of distortions of the average flow remains practically constant, but an increase in nonstationary disturbances is observed. It was found that the greatest increase in pulsations caused by Mach waves is observed in the area of the maximum gradient of the average flow. It is found that an increase in the number ReLleads to an expansion of the frequency range of unstable disturbances generated by a pair of weak shock waves.
{"title":"Research on the Influence of the Unit Reynold’s Number on the Characteristics of N-Waves at M = 2.5","authors":"Yulia I. Usynina, Y. Yermolaev, A. Kosinov, N. Semionov","doi":"10.25205/2541-9447-2021-16-1-53-64","DOIUrl":"https://doi.org/10.25205/2541-9447-2021-16-1-53-64","url":null,"abstract":"This paper presents the results of studying the features of the development of weak shock waves generated by a twodimensional roughness on the wall of the working part of a supersonic wind tunnel in a free flow at a Mach number of 2.5. The measurements were performed with a constant resistance thermoanemometer. It is shown that a twodimensional sticker induces weak shock waves into the free flow. They cause distortion of the average flow, the shape of which corresponds to the N-wave. High-intensity pulsations were recorded in the region of passage of a pair of weak shock waves. With an increase in the unit Reynolds number, the level of distortions of the average flow remains practically constant, but an increase in nonstationary disturbances is observed. It was found that the greatest increase in pulsations caused by Mach waves is observed in the area of the maximum gradient of the average flow. It is found that an increase in the number ReLleads to an expansion of the frequency range of unstable disturbances generated by a pair of weak shock waves.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"8 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89900315","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}
Pub Date : 2021-01-01DOI: 10.25205/2541-9447-2021-16-1-5-20
V. P. Zhukov, A. Bulgakov, N. Bulgakova
The interaction of femtosecond laser pulses of moderate intensity with metals by the example of gold is studied. The main attention is paid to dichromatic regimes of laser irradiation corresponding to a new trend in the field of laser pro-cessing of materials. Based on the two-temperature approximation, a new model is created which involves a dichro-matic source of the laser radiation energy and also takes into account the influence of the electron temperature on the reflection coefficient of the irradiated material and thermophysical properties of its electronic subsystem. For numerical implementation of the model, an implicit divergent finite-difference scheme is created with an improved method for describing the melting process in comparison with previous works. The model calculations have shown that the absorption of the laser energy by gold depends on the sequence of two pulses at different wavelengths and the delay time between them, and for correct description of the absorbed energy, it is necessary to take into account the change of the reflection coefficient of the surface during irradiation. The developed model may be of interest for optimizing the processing of materials with ultra-short dichromatic laser pulses.
{"title":"Numerical Study of the Dynamics of Gold Heating by Ultra-Short Dichromatic Laser Pulses","authors":"V. P. Zhukov, A. Bulgakov, N. Bulgakova","doi":"10.25205/2541-9447-2021-16-1-5-20","DOIUrl":"https://doi.org/10.25205/2541-9447-2021-16-1-5-20","url":null,"abstract":"The interaction of femtosecond laser pulses of moderate intensity with metals by the example of gold is studied. The main attention is paid to dichromatic regimes of laser irradiation corresponding to a new trend in the field of laser pro-cessing of materials. Based on the two-temperature approximation, a new model is created which involves a dichro-matic source of the laser radiation energy and also takes into account the influence of the electron temperature on the reflection coefficient of the irradiated material and thermophysical properties of its electronic subsystem. For numerical implementation of the model, an implicit divergent finite-difference scheme is created with an improved method for describing the melting process in comparison with previous works. The model calculations have shown that the absorption of the laser energy by gold depends on the sequence of two pulses at different wavelengths and the delay time between them, and for correct description of the absorbed energy, it is necessary to take into account the change of the reflection coefficient of the surface during irradiation. The developed model may be of interest for optimizing the processing of materials with ultra-short dichromatic laser pulses.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"17 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85121265","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}
Pub Date : 2021-01-01DOI: 10.25205/2541-9447-2021-16-1-101-108
S. Gilev, V. S. Prokopiev
Electrical resistance measurements of aluminum foil are conducted under shock compression using the electric contact technique. Shock wave pressure p dependences of the electrical resistance R and the resistivity r are obtained for pressure range up to 22 GPa. The found dependence R(p) is a monotonically increasing smooth function of the pressure. The dependence r(p) is more complex: with increasing pressure, the electrical resistivity first decreases and then increases.
{"title":"Electrical Resistivity of Aluminum under Shock Compression","authors":"S. Gilev, V. S. Prokopiev","doi":"10.25205/2541-9447-2021-16-1-101-108","DOIUrl":"https://doi.org/10.25205/2541-9447-2021-16-1-101-108","url":null,"abstract":"Electrical resistance measurements of aluminum foil are conducted under shock compression using the electric contact technique. Shock wave pressure p dependences of the electrical resistance R and the resistivity r are obtained for pressure range up to 22 GPa. The found dependence R(p) is a monotonically increasing smooth function of the pressure. The dependence r(p) is more complex: with increasing pressure, the electrical resistivity first decreases and then increases.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"37 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90101942","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}
Pub Date : 2021-01-01DOI: 10.25205/2541-9447-2021-16-1-65-80
I. Sadovsky, M. Katasonov, A. Pavlenko
In a wind tunnel on a flat plate in a separated flow behind a rectangular step, the emergence and development of localized disturbances generated by low-frequency impulse deviations of the local surface section under conditions of low and moderate degrees of the incoming flow turbulence is studied. The results were obtained by hot-wire anemometry at low subsonic flow velocity. It was found that impulse deviations of the wall generate disturbances, which are socalled Streaky structures and wave packets of oscillations. The separation of the laminar boundary layer accelerates the growth of wave packets with subsequent turbulization of the near-wall flow. The specific features of the behavior of localized disturbances under conditions of moderate degree of free-stream turbulence are revealed.
{"title":"Investigation of the Development of Localized Disturbances in the Boundary Layer of a Flat Plate under Conditions of Moderate Degree of the Incoming Flow Turbulence behind the Surface Step","authors":"I. Sadovsky, M. Katasonov, A. Pavlenko","doi":"10.25205/2541-9447-2021-16-1-65-80","DOIUrl":"https://doi.org/10.25205/2541-9447-2021-16-1-65-80","url":null,"abstract":"In a wind tunnel on a flat plate in a separated flow behind a rectangular step, the emergence and development of localized disturbances generated by low-frequency impulse deviations of the local surface section under conditions of low and moderate degrees of the incoming flow turbulence is studied. The results were obtained by hot-wire anemometry at low subsonic flow velocity. It was found that impulse deviations of the wall generate disturbances, which are socalled Streaky structures and wave packets of oscillations. The separation of the laminar boundary layer accelerates the growth of wave packets with subsequent turbulization of the near-wall flow. The specific features of the behavior of localized disturbances under conditions of moderate degree of free-stream turbulence are revealed.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"37 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73758139","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}
Pub Date : 2020-10-02DOI: 10.17516/1997-1397-2020-13-6-733-745
Zhobir K. Adashev, T. Kurbanbaev
We investigate almost inner derivations of some finite-dimensional nilpotent Leibniz algebras. We show the existence of almost inner derivations of Leibniz filiform non-Lie algebras differing from inner derivations, we also show that the almost inner derivations of some filiform Leibniz algebras containing filiform Lie algebras do not coincide with inner derivations
{"title":"Almost Inner Derivations of Some Nilpotent Leibniz Algebras","authors":"Zhobir K. Adashev, T. Kurbanbaev","doi":"10.17516/1997-1397-2020-13-6-733-745","DOIUrl":"https://doi.org/10.17516/1997-1397-2020-13-6-733-745","url":null,"abstract":"We investigate almost inner derivations of some finite-dimensional nilpotent Leibniz algebras. We show the existence of almost inner derivations of Leibniz filiform non-Lie algebras differing from inner derivations, we also show that the almost inner derivations of some filiform Leibniz algebras containing filiform Lie algebras do not coincide with inner derivations","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"169 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76538773","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}
Pub Date : 2020-10-01DOI: 10.17516/1997-1397-2020-13-5-568-573
N. Imanbaev
A spectral problem for a multiple differentiation operator with integral perturbation of boundary value conditions which are regular but not strongly regular is considered in the paper. The feature of the problem is the absence of the basis property of the system of root vectors. A characteristic determinant of the spectral problem is constructed. It is shown that absence of the basis property of the system of root functions of the problem is unstable with respect to the integral perturbation of the boundary value condition
{"title":"On a Problem that Does not Have Basis Property of Root Vectors, Associated with a Perturbed Regular Operator of Multiple Differentiation","authors":"N. Imanbaev","doi":"10.17516/1997-1397-2020-13-5-568-573","DOIUrl":"https://doi.org/10.17516/1997-1397-2020-13-5-568-573","url":null,"abstract":"A spectral problem for a multiple differentiation operator with integral perturbation of boundary value conditions which are regular but not strongly regular is considered in the paper. The feature of the problem is the absence of the basis property of the system of root vectors. A characteristic determinant of the spectral problem is constructed. It is shown that absence of the basis property of the system of root functions of the problem is unstable with respect to the integral perturbation of the boundary value condition","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"T156 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82652502","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}
Pub Date : 2020-06-16DOI: 10.17516/1997-1397-2020-13-5-547-558
A. Polkovnikov
We consider initial boundary value problem for uniformly 2-parabolic differential operator of second order in cylinder domain in Rn with non-coercive boundary conditions. In this case there is a loss of smoothness of the solution in Sobolev type spaces compared with the coercive situation. Using by Faedo-Galerkin method we prove that problem has unique solution in special Bochner space
{"title":"On Initial Boundary Value Problem for Parabolic Differential Operator with Non-coercive Boundary Conditions","authors":"A. Polkovnikov","doi":"10.17516/1997-1397-2020-13-5-547-558","DOIUrl":"https://doi.org/10.17516/1997-1397-2020-13-5-547-558","url":null,"abstract":"We consider initial boundary value problem for uniformly 2-parabolic differential operator of second order in cylinder domain in Rn with non-coercive boundary conditions. In this case there is a loss of smoothness of the solution in Sobolev type spaces compared with the coercive situation. Using by Faedo-Galerkin method we prove that problem has unique solution in special Bochner space","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"26 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89806047","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}
Pub Date : 2020-06-01DOI: 10.17516/1997-1397-2020-13-3-342-349
N. Zhuk, V. Lutoev, D. Beznosikov, A. N. Nizovtsev, L. Rychkova
Magnetic susceptibility, microstructure and EPR of cobalt-containing solid solutions with layered perovskite-like structure Bi5Nb3−3xCo3xO15−δ have been studied. Solid solutions of Bi5Nb3−3xCo3xO15−δ (x60.005) can be crystallized in tetragonal syngony (sp. gr. P4/mmm), as cobalt content increases, monoclinic distortion of the unit cell emerges at 0.005 < x 6 0.04 (sp. gr. P2/m). The formation of exchange-bound aggregates of Сo(III) and Co(II) atoms predominantly with antiferromagnetic exchange types has been found in the solid solutions. EPR indirectly confirms that cobalt ions are in octahedral positions of substitution of Nb(V) ions
研究了层状钙钛矿状Bi5Nb3−3xCo3xO15−δ含钴固溶体的磁化率、微观结构和EPR。固溶体Bi5Nb3−3xCo3xO15−δ (x60.005)可以呈四方共晶(sp. gr. P4/mmm)，随着钴含量的增加，在0.005 < x6 0.04 (sp. gr. P2/m)处出现单斜畸变。在固溶体中，发现Сo(III)和Co(II)原子主要以反铁磁交换类型形成交换键聚集体。EPR间接证实钴离子在八面体位置取代Nb(V)离子
{"title":"Magnetic Susceptibility and EPR Study of Bi₅Nb₃−₃ₓCo₃ₓO₁₅−δ","authors":"N. Zhuk, V. Lutoev, D. Beznosikov, A. N. Nizovtsev, L. Rychkova","doi":"10.17516/1997-1397-2020-13-3-342-349","DOIUrl":"https://doi.org/10.17516/1997-1397-2020-13-3-342-349","url":null,"abstract":"Magnetic susceptibility, microstructure and EPR of cobalt-containing solid solutions with layered perovskite-like structure Bi5Nb3−3xCo3xO15−δ have been studied. Solid solutions of Bi5Nb3−3xCo3xO15−δ (x60.005) can be crystallized in tetragonal syngony (sp. gr. P4/mmm), as cobalt content increases, monoclinic distortion of the unit cell emerges at 0.005 < x 6 0.04 (sp. gr. P2/m). The formation of exchange-bound aggregates of Сo(III) and Co(II) atoms predominantly with antiferromagnetic exchange types has been found in the solid solutions. EPR indirectly confirms that cobalt ions are in octahedral positions of substitution of Nb(V) ions","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"49 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75281572","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}
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