Home – Home – Jornals – Thermophysics and Aeromechanics 2012 number 1

In the present paper, we summarize our experimental data on flow separation control on wings at low subsonic velocities. The focus is on the reduction of the separation region by stationary and nonstationary controlled flow perturbations. Wind-tunnel data obtained for test models of different aspect ratios prove that the entire separated flow can be modified by forcing its narrow parts much smaller in size than the transverse extent of the separation region. Such an approach to flow control at laminar separation comes from non-local interaction of the large-scale flow structure with spatially concentrated disturbances.

In the present article, we investigate the possibility of using simple physical models for predicting properties of incompressible turbulent boundary layer on permeable wall at various values of air-microblowing mass flow rate. It is shown that the velocity scaling U_{∞δ^{*/δ99 can be successfully used to approximate the distribution of mean velocity in the outer region of the boundary layer. The use of this scaling makes the velocity profiles invariant with respect to Reynolds-number variation; this circumstance largely facilitates the analysis of experimental data, making it independent of upstream flow conditions. The distribution of mean velocity in the logarithmic flow region of the boundary layer over permeable surface can be described with a modified law of the wall involving a constant C0 equal to the same constant for canonical boundary layer, and a quantity K being a weak function of blowing ratio.}}

The entry of a shock wave with the Mach number M_is = 2.03 into a microchannel and its further propagation is numerically studied with the use of kinetic and continuum approaches. Numerical simulations on the basis of the Navier ⎯ Stokes equations and the Direct Simulation Monte Carlo method are performed for different Knudsen numbers Kn = 8·10⁻³ and 8·10⁻² based on the microchannel half-height. At the Knudsen number Kn = 8·10⁻³, amplification of the shock wave after its entry into the microchannel is observed. Further downstream, the shock wave is attenuated, which is in qualitative agreement with experimental data. It is demonstrated that results predicted by a quasi-one-dimensional model (which ignores viscosity and heat conduction) of shock wave propagation over a channel with an abrupt change in the area agrees with results of numerical simulations on the basis of the Euler equations. In both cases, shock wave acceleration (amplification) after its entry into the microchannel is observed. At the Knudsen number Kn = 8·10⁻², the influence of the entrance shape on shock wave propagation over the microchannel is examined. Intense attenuation of the shock wave is observed in three cases: channel with sudden contraction, junction of two channels with an additional thin separating plate, and rounded junction in the form of a sector with an angle of 90° (quarter of a circumference). It is shown that the microchannel entrance shape can affect further propagation of the shock wave. The wave has the highest velocity in the case with a rounded entrance.

Laminar mixed convective buoyancy assisting flow through a two-dimensional vertical duct with a backward-facing step using nanofluids as a medium is numerically simulated using finite volume technique. Different types of nanoparticles such as Au, Ag, Al₂O₃, Cu, CuO, diamond, SiO₂ and TiO₂ with 5 % volume fraction are used. The wall downstream of the step was maintained at a uniform wall temperature, while the straight wall that forms the other side of the duct was maintained at constant temperature equivalent to the inlet fluid temperature. The walls upstream of the step and the backward-facing step were considered as adiabatic surfaces. The duct has a step height of 4.9 mm and an expansion ratio of 1.942, while the total length in the downstream of the step is 0.5 m. The downstream wall was fixed at uniform wall temperature 0 ≤ ΔT ≤ 30 °С, which was higher than the inlet flow temperature. The Reynolds number in the range of 75 ≤ Re ≤ 225 was considered. It is found that a recirculation region was developed straight behind the backward-facing step which appeared between the edge of the step and few millimeters before the corner which connect the step and the downstream wall. In the few millimeters gap between the recirculation region and the downstream wall, a U-turn flow was developed opposite to the recirculation flow which mixed with the unrecirculated flow and traveled along the channel. Two maximum and one minimum peaks in Nusselt number were developed along the heated downstream wall. It is inferred that Au nanofluid has the highest maximum peaks while diamond nanofluid has the highest minimum peak. Nanofluids with a higher Prandtl number have a higher peak of Nusselt numbers after the separation and the recirculation flow disappeared.
Key words: mixed convection, buoyancy-assisted flow, backward-facing step, nanofluids.

Numerical simulation of metal surface alloying with impulse laser radiation has been performed. Impulse intensity influence on melt hydrodynamics and alloying substance distribution has been evaluated. For substance material, the authors used data on iron including dependence of surface tension on melt temperature and admixture concentration.

The mathematical model of radiation field in a semi-transparent medium formed under the action of incident collimated and diffusion radiation was developed and implemented numerically. To solve the problem, the approach on the basis of modified average flux method was developed. Method testing via comparison with results of other authors has proved its high reliability and accuracy. As an example, the effect of different factors on radiation field was analyzed: self-radiation of medium, scattering anisotropy, and bottom reflectance.

Unsteady flow and heat transfer of the heated cylinder with transverse and longitudinal oscillations in unbounded flow of viscous incompressible heat conducting fluid are considered. Influence of amplitude, frequency and direction of harmonic oscillations of the cylinder on the near-wake structure and heat transfer are investigated.

Experimental study was performed for operation of a centrifugal disk pump at atmospheric air pressure. The dimensionless parameters were developed for generalization of experimental data on flow rate and head of the pump. The method for calculation of a pumping curve and throttling characteristic was offered through use of semiemperical generalization formulas. The method ensures a good accuracy in calculations, which is proved by comparison of calculation and experimental data for the pump tested.

The modification of absorption optic method for diagnostics of the wave liquid film on the surface of a rotating disk was proposed. Inaccuracy of the method was estimated analytically and experimentally. The field measurements of liquid film thickness on a rotating disk were carried out.

Evolution of disturbances on the surface of liquid film falling free over a vertical plane is considered. In the case of low Reynolds numbers, the problem is reduced to investigation of a single equation describing evolution of film thickness disturbances. With the use of information about the structure of the family of steady-state traveling solutions to this equation, the typical scenarios of evolution for periodic disturbances were identified.

The process of development of the third heat transfer crisis for vertical orientation of the heating surface was studied experimentally. Experiments were carried out with acetone under the conditions of saturation for the pressures in the working volume from 20 to 28 kPa. In all experiments, the third heat transfer crisis was preceded by propagation of evaporation front along the heating surface. The threshold values of heat flux densities, above which a stable vapor film is formed on the whole heating surface, are lower for vertical orientation of this heating surface than for the horizontal one. Data on the threshold heat flux densities and overheating before boiling-up were obtained. Above these values, formation of evaporation fronts was observed. The range of operation parameters corresponding to formation of the sites of unstable film boiling on the heating surface after boiling-up was determined.

Investigation results on hydrodynamics, heat transfer, and crisis phenomena in laminar-wave liquid films falling down the surfaces of different geometry are presented in this study. Freon mixture R21/R114 with initial concentration of low-boiling component of 4−16.6 % was used as the working liquid. The film Reynolds number at the inlet to the experimental section varied from 60 to 700. The heat flux density was changed within 0−5 W/cm². The images of wave surface of the falling liquid film and formation of dry spots were visualized and recorded by the high-speed video camera. Results of investigation of the wave structure of the film surface, measurements of heat transfer coefficients under the conditions of boiling, and critical heat fluxes in the film flow over the smooth and structured surfaces are presented.

The work is devoted to investigation of thermophysical processes occurring at granulation of lead-containing aluminum alloys. The researchers proposed the mathematical model of heat transfer that served a basis for calculation of cooling of the alloy drops with different dimensions. With the use of laboratory experiment, the boundary conditions of simulation have been specified, and the quality of the obtained granules evaluated.

The article presents results of the research of particulate matter and droplets removal on inclined tubes of the flue gas cleaning condenser in the process of vapor condensation of vapor-and-gas emissions from kraft pulp production.

The models of thermal conductivity in fibrous spatially reinforced medium were developed at overall anisotropy of components; the approach is based on equality between dissipation in equivalent material and  the considered composite. The calculated values of effective coefficients of thermal conductivity for two cases (unidirectional and cross-loaded) composites were compared with experimental data. Agreement between calculated and experimental data is satisfactory. It was demonstrated that developed models give the upper and lower estimates for effective coefficients of thermal conductivity in fibrous compositions.

The essence of the concepts of dialogue and communication is revealed. There is performed an analysis of the various approaches to the problem of dialogue. There is considered the value-related aspect of understanding by the child of the content of education, conducive to the formation of the personal system of values.

The purpose of the article is to analyze the problem of moral upbringing of rural senior pupils in the context of historical and philosophical understanding of the human being.
In the article, the features and capabilities of the rural society in moral upbringing of senior schoolchildren are revealed.

In the article, there are explained the main positions of the modern ethics of the children-parents relations. In the family, there are laid foundations of the morality of the person, the norms of behaviors are formed, the inner world and individual features of the personality are revealed. The family not only fosters the formation of personality but also self-affirmation of the person, stimulates his/her social, creative activity, reveals the individuality.
The insufficient experience of working with adolescents while taking into account the specificity of contemporary urban and rural society does not allow effectively realizing the full potential of upbringing-preventive influence on the minor, his/her family, prevents the timely and proper identification of the nature of deviant behavior, adverse factors that foster deviation and hinders the working out the preventive measures.

The article analyses the theoretical approaches of foreign and Russian researchers to the concept of organizational culture, discloses the essence and content of organizational culture and its elements

In the article, there is presented an analysis of modern scientific-theoretical approaches to the examination of general questions of education of the person of culture, there are considered the philosophical aspects of the essence of the musical culture of personality. The authors perform an analysis of the structural components of musical culture on the basis of social-historical, sociological, activity-related and cultural approaches.

In the article, there are considered the questions of using the communication traditions of the Sakha people, creating the conditions for the informational cooperation of children with people and nature in the ethnic-cultural space of the village. The major problem is the search for the effective methods, the elaboration of the mechanism of development of the speech communication culture of the children of preschool age. The article considers the traditions of communication of the Sakha people, the levels of development of the speech communication of children and the forms of working with them. The authors distinguish certain connections between the communication of the child with the surrounding people and the traditions which can be used in the development of childrens speech culture.

In the article, there is considered the problem of training of the qualified personnel and the middle level specialists in the conditions of labor market and the production growth, the formation of modern numerous middle class as a foundation of social stability. There are substantiated the topical directions of innovative development of the Yakutsk agricultural technical school: modernization of educational activities, informatization of education, development of research activities, spiritual and physical development of students, strengthening of the material technical base, improvement of the list of the trainees specialties.

In the article, the problem of training of the young teacher for the administrative activity in the school is touched upon, the special features of administrative culture as a sign of professionalism are described. There is presented a pedagogical technology of formation of the administrative culture of the young teacher as a condition of integrity of this process and raising his/her professional level.

The article presents the theoretical-methodological and conceptual approaches to the problem of professional development of the young specialists in rural schools. The author analyzes the theoretical positions on the formative process and development of the person, reveals the formative stages of professional teachers, defines the professional formation of young specialists of rural schools as a continuous process of the professional competence acquiring by the young professional, manifested in his/her self-development and self-realization in the pedagogical activities.

The article deals with some aspects of personal and vocational formation of the teacher, who works with disabled children. The article regards the question of continuous vocational teacher training of teachers-defectologists in the Republic of Sakha (Yakutiya).

In the article, there is considered the problem of pedagogical activities of the teacher of primary classes in the conditions of the new educational standard. There are substantiated the topical directions of development of the pedagogical activities of the teacher: modernization of educational activity, modern education, professional self-education. There are also considered the nature and content of the concepts of personality formation, pedagogical innovation, innovative processes, the state standard

In the article, there are considered the topical issues of designing a new system of development of the rural educational institution, forming the corresponding philosophical foundation, and studying various aspects of activity of the rural school.

During life-time Makarenko as innovator-educator was criticized from the left and right. He was accused of enthusiasm of pre-revolutionary pedagogy, striving for approval of authoritarianism, discipline. Since the late 80 s there were numerous publications where attempts had been made to assess creativity of Makarenko with contemporary positions. However, the question about the place of Makarenko in pedagogical theory and practice is remained debatable.

In the article, there are considered the pedagogical ideas and practical experience of upbringing of A.S. Makarenko in the context of the main trends in the historical development of the domestic and world pedagogical classics: the school of studies and the school of life. There is substantiated the thesis that Makarenko is a bright representative of the upbringing pedagogy and the school of life.

In the article, there are considered the philosophical aspects of self-organization of the studying activity. Analyzing the works of philosophers of various historical periods, the author concludes that the main role in ordering the activity belongs to the activeness of the person him/herself.

In the article, there is presented a generalization of the problem of developing the personality in the process of additional education; there are revealed the conceptual bases of the additional education, its goals and the priority ideas. There are distinguished and considered the common personality qualities of the youth that must be developed for the successful future by means of additional education.

In the article, there is described a hypothesis of formation of a concept of «technological human being» from the point of view of the transformation of social experience from generation to generation in the framework of the creation of various authors schools.

The purpose of the article is to study a meaning-forming approach to the development of personality in the spiritual-moral sphere. The main topic of the article is organization of the meaning-forming context of education in the pre-school childhood. The author pays attention to the meaning-forming essence of the folk upbringing culture and considers as necessary the inclusion of the oral folklore reading by children into the educational system, which would foster their spiritual-moral development.

In the article, there is shown the interrelation between the pedagogical creativity and research activities of the teacher on the basis of similarity between the existing ideas about the stages of scientific creativity and the phases of pedagogical creativity. There is also presented the research position of the teacher in working out new solutions as a result of analyzing and generalizing of his/her own and the state-of-the-art experience.

In the article, there is considered the problem of self-development and self-actualization of the person, one of the priority problems of modern philosophy, pedagogy and psychology. There is describes the contents and the particularities of creative self-development of the higher education teacher as one of the most important components of his/her professional activity. There are determined the conditions, stages, and technologies of formation of the professionally oriented creative self-development of the higher education pedagogue. There are presented the results of preliminary research on the readiness of the higher education teacher for the innovative activity, which presupposes the presence of a high level of development of creative abilities.

In the modern society, the problem of professional-personal development of the teacher and its readiness for innovative activity is especially acute and topical. The purpose of the article is to search for innovative forms and methods of teaching.
There are presented the authors educational programs developed in an innovative mode of school. The teachers-authors adhere to the principles of the personality-focused and humanistic approaches in the technique of teaching. There are considered the questions of improvement of the quality of pedagogical process in education. In the article, a comparative analysis is given of the traditional system of teaching and the innovative technologies in the schoolchildren training.

In the article, we consider the scientific-methodical support of the research work of the post-graduate students through realization of the case-technology. A special significance for implementation of the case-technology has the elaboration of the main educational program for post-graduate students, majoring in General pedagogy, History of pedagogy and education.

In the article, there is considered, using the means of a design approach, the creative personality becoming in the process of the creative activity formation. The author thinks that it is exactly the design approach that is able to provide the students reaching the level of education that would create a foundation for the formation of a self-developing creative personality, capable of independently solving the problems in various spheres of life activity.

In the article, there is described the military-patriotic orientation of physical education and sports in the years of the World War II in Yakutiya. The general pedagogical essence of self-education and mobility of people masses in the special situation of war in the military patriotic spirit is emphasized. There are presented convincing historical facts about intensification of the physical, sport and defense work, where there was manifested the confidence and the firm faith of the people in the victory.Key words:patriotism, the World War II, military patriotic spirit, firm faith of people, military- sportswork, peoples hero, the development of physical training and sport.

There are considered the theoretical bases, methodology and a model of psychological-pedagogical support of young sportsmen (purposes, tasks, peculiarities, stages of complex maintenance, methods and forms, regularities, terms and expected results), its practical importance in the children-youth sport. There are revealed the components of young sportsmen selection and the process of sports career support, formation of young sportsmens personality, achievements of success in sports and life.