Journal of Siberian Federal University-Mathematics & Physics最新文献

{"title":"Application of Accelerometers for Measuring Aerodynamic Forces in Short-Term Facilities","authors":"A. Maslov, A. Starov, I. S. Tsyryulnikov","doi":"10.25205/2541-9447-2022-17-3-22-28","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-3-22-28","url":null,"abstract":"Methods for restoring aerodynamic forces based on the use of measurement data by balance elements and an accelerometer have been expanded. A signal processing method has been developed that makes it possible to correct the measurement data of balance elements using additional data on the acceleration of support elements. Examples of the application of the proposed method under the conditions of a pulsed wind tunnel in experiments on massive models, both with constant and decreasing flow parameters during the test, are given. An increase in the measurement accuracy of single-component force-measuring sensors is shown.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"20 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83633177","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}

{"title":"Investigation of a Radiofrequency Plasma Generator for Multi-Second Pulse Operation","authors":"V. A. Vointsev, D. Y. Gavrisenko, A. Kondakov, O. Sotnikov, R. A. Finashin","doi":"10.25205/2541-9447-2022-17-3-5-11","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-3-5-11","url":null,"abstract":"This paper presents the test results of a radiofrequency (RF) plasma generator, developed for neutral beam injectors. A water cooled faraday screen is installed into the generator for multi-second pulse operation. Consistent operation achieved for 20-second long pulses with input power of 38 kW is described. The density of the ion current was measured. The experiments were conducted to measure the density of the ion current at the driver’s output and to evaluate the heating of the driver’s elements. Main factors affecting the power losses were determined. The power loss caused by the eddy currents in the driver’s clamping flanges were reduced.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"71 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74985380","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}

{"title":"Study of the Regimes of Diffusive Combustion of a Hydrogen Microjet","authors":"V. Kozlov, M. Litvinenko, Yu. A. Litvinenko, A. Tambovtsev, A. Shmakov","doi":"10.25205/2541-9447-2022-17-3-12-21","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-3-12-21","url":null,"abstract":"The paper presents the results of experimental studies of scenarios of diffusion combustion of a microjet of hydrogen flowing out of a cylindrical micronozzle with a diameter of 200 μm. The hydrogen microjet is ignited near the nozzle exit and at a distance. The experimental data are compared with the data previously obtained, and the results are expressed in dimensionless parameters (in terms of Reynolds numbers). It is established that the stabilization of flame during the outflow of a circular micro jet of hydrogen is associated with the presence of heating of the nozzle by a spherical flame region covering the nozzle section. The hysteresis of the diffusion combustion process of circular hydrogen microjets is shown depending on the ignition location of the microjet (near or far from the nozzle exit) and the change in the flow rate (growth or decrease).","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"440 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83646006","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}

{"title":"Two-stage carbon condensation model during detonation of high explosives","authors":"I. Rubtsov","doi":"10.25205/2541-9447-2022-17-2-48-55","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-48-55","url":null,"abstract":"During detonating of high explosives with a negative oxygen balance, one of the products of the chemical reaction is condensed carbon. However, the lack of experimental data does not allow us to give a quantitative assessment of the carbon condensation process today. In this paper, a two-stage model of carbon condensation during the detonation of high explosives is proposed. We used small-angle X-ray scattering method to study the dynamics of the formation of carbon nanoparticles during the detonation of charges of a mixture of TNT and RDX.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78557947","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}

{"title":"Flame Structure of Ammonia/Hydrogen/Oxygen/Argon Mixtures at High Pressure","authors":"K. N. Osipova, A. Shmakov","doi":"10.25205/2541-9447-2022-17-2-56-68","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-56-68","url":null,"abstract":"The search of alternative fuels is one of the most important issues. Hydrogen is the most attractive one since its combustion products include only water. However, due to its specific properties wide implementation of hydrogen is not possible. There is an idea to use chemical carriers of hydrogen, for example, ammonia. The addition of hydrogen, which is the product of ammonia cracking, can improve the combustion characteristics of ammonia. The work presents experimental data on the structure of NH3/H2/O2/Ar flames at 4 atm. Equivalence ratio values were 0.8, 1.0 and 1.2, NH3/H2 ratio – 1/1. Flame structure was measured with molecular beam mass spectrometry with soft electron impact ionization. In the experiments, flames were stabilized on the flat burner. Temperature profiles were measured with thin S-type thermocouples. Numerical simulations were performed with PREMIX code from CHEMKIN package. The comparison of the experimental and numerical data enabled to reveal the mechanism of NH3/H2 oxidation showing the best predictive capability. Experimental and numerical data showed that the nitrogen-containing species which are present in the post-flame zone are N2 and NO whereas concentration of N2O and NO2 is negligible. It was revealed that in terms of NO reduction slightly rich conditions are more effective. In addition, the effect of equivalence ratio on the peak concentration of NO, N2O and NO2 was analyzed. Rich conditions appeared to be more effective to reduce peak concentrations of NO, N2O and NO2.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"1 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88738514","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}

{"title":"Investigation of the Increment of Transverse Instability of a Kiloampere Electron Beam in a Linear Induction Accelerator for Its Use in a Terahertz FEL","authors":"E. Sandalov, S. Sinitsky, D. I. Skovorodin, A. V. Arzhannikov, P. Logachev, P. Bak, K. Zhivankov, D. Nikiforov, A. Petrenko, N. Ginzburg, N. Peskov, R. V. Protas","doi":"10.25205/2541-9447-2022-17-2-16-29","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-16-29","url":null,"abstract":"The Institute of Nuclear Physics SB RAS in cooperation with the Russian Federal Nuclear Center VNIITF performs a series of researches aimed at acquiring a relative electron beam with energy up to 20 MeV, current up to 2 kA, and duration up to 200 ns at normalized emittance ca. 1000 π∙mm∙rad in a linear induction accelerator (LIA). In order to generate electron beams with such parameters we require thorough investigation of all main sources of perturbation of electron beam trajectory caused by different instabilities that occur during the transport and acceleration of a high currency beam in the accelerating structure of LIA. For the experimental series on measuring the dynamics of transverse oscillation of a beam, we applied a set of fast current transformers which are used for registration of beam current and mode fields caused by this beam in the structure. These measurements were performed for the electron beam with the energy of 8.5 MeV and current of 1 kA going through the structure at different modes of focusing magnetic fields size in LIA. As a result, we registered oscillation of the electromagnetic field of normal modes in the accelerating modules of LIA, as well as we determined the dependence of the oscillation amplitude of these modes’ EM field on the number of accelerating module. This dependence was compared with the result of modeling of development dynamics of transverse instability in LIA that was performed using the created program system. This allowed us to determine the size of the increment of transverse instability of a relativistic electron beam under the given experimental conditions. Based on the acquired results, we made the analysis of possibility to use the beam generated in ILA as a driver for the FEL generator of coherent impulses of THz radiation within the frequency range of 0.3–1.2 THz with a sub-gigawatt level of power.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"32 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74231901","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}

{"title":"Lecture demonstrations of experiments in physics at the Novosibirsk State University","authors":"E. Palchikov, V. Seleznev, E. G. Alekseev","doi":"10.25205/2541-9447-2022-17-2-93-104","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-93-104","url":null,"abstract":"The article tells about the 60-year history of the creation of a set of basic lecture demonstrations at the Physical Department of the Novosibirsk State University and about the subdivision for demonstrations support – from the moment the university was founded. The evolution of a set of demonstration installations, methodological descriptions andtechniques for using equipment in the process of teaching physics in various situations is considered. It tells about the people who made a great contribution at different stages of the transformation of DKF – a demonstration room in physics and MLDKS – an interfaculty laboratory of demonstrations and computer support. Bibliographic references to catalogs with methodological descriptions of lecture demonstrations developed and created at NSU are given.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"38 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83297307","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}

{"title":"Experimental study of effect of a pair of weak shock waves on laminar-turbulent transition in the boundary layer of flat plate at Mach number 2","authors":"M. V. Piterimova, А. D. Kosinov, N. Semionov, A. Yatskikh, V. Kocharin, Y. Yermolaev","doi":"10.25205/2541-9447-2022-17-2-30-40","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-30-40","url":null,"abstract":"An experimental study of the effect of longitudinal vortices generated by weak shock waves on the laminar-turbulent transition in the boundary layer of a flat plate at a Mach number 2 is conducted. To amplify the effect of the longitudinal vortices generation, a model with leading edge blunting radius of 0,5 mm was used. The disturbance intensity was measured with a constant temperature hotwire anemometer and a single-wire sensor. To change the Reynolds numbers in the flow, the method of varying the pressure in the pretest section of a supersonic wind tunnel was used. According to the experimental conditions, the level of mass flow perturbations in the test section T325 of ITAM SB RAS did not exceed 0,1 % of the mean flow in the frequency range from 0,2 to 50 kHz. In this work, it is obtained for the first time that stationary streamwise vortices that arise in the boundary layer of a flat plate because of the action of a pair of weak shock waves on its leading edge lead to an early laminar-turbulent transition at different Reynolds numbers. In the case of a homogeneous boundary layer, the transition is achieved at Rex ≈ 3,1 × 106, and in measurements in the region of vortices from shock waves at Rex ≈ 1,5 × 106 and Rex ≈ 2 × 106.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"20 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72753937","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}

{"title":"Chair of Continuous Media Physics","authors":"E. Palchikov, M. Kotelnikova","doi":"10.25205/2541-9447-2022-17-2-81-92","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-81-92","url":null,"abstract":"The paper talks about the history of the creation of the Chair of Continuous Media Physics of the Physics Department of NSU, the scientific achievements of its employees and graduates, the teaching methods and hints, the fields of interest in science.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"82 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86668886","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}

{"title":"Section of Physical Methods of Solid State Research of the Department of Physics of Novosibirsk State University","authors":"S. Tsybulya","doi":"10.25205/2541-9447-2022-17-2-75-80","DOIUrl":"https://doi.org/10.25205/2541-9447-2022-17-2-75-80","url":null,"abstract":"The article is devoted to the Department of Physical Methods for Solid Research of the Physics Department of Novosibirsk State University, the basic institutes of which are the Boreskov Institute of Catalysis and the Nikolaev Institute of Inorganic Chemistry of the Siberian Branch of the Russian Academy of Science. It tells about the history of the foundation of the department, its lecturers and the directions of their scientific research, and also about the disciplines studied. The reader can get acquainted with the list of department’s master’s programs and with the achievements of its graduates and the prospects for further development.","PeriodicalId":43965,"journal":{"name":"Journal of Siberian Federal University-Mathematics & Physics","volume":"154 1","pages":""},"PeriodicalIF":0.4,"publicationDate":"2022-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86785839","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}