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Direct and indirect skin friction measurement techniques that are most widely used in practice are reviewed and briefly characterized. A comparative analysis of measurement results is given for some methods used in an incompressible turbulent boundary layer on a flat plate under conditions of a positive (adverse) stream-wise pressure gradient formed on the plate surface and in a gradient-free flow. The degree of efficiency of the above methods is demonstrated, and their application range and the limits are shown. P.475-491

Experimental results of subsonic flow over a straight wing model are described. On the surface near the leading edge a local separation bubble exists, and besides, downstream the separation of turbulent boundary layer in the trailing part of a wing is observed. A three-dimensional vertical structure of flow is noted using visualization. By means of hot-wire measurements the quantitative data on distribution of mean velocity of flow above a wing, as well as on amplitude and frequency spectra of pulsations are obtained. P. 493-498

The distribution of axisymmetric disturbances of the velocity field in a convective column from a source of the momentum moment and/or heat is investigated. A system of differential equations for the amplitude functions of the axial and azimuth velocity, momentum moment, the pressure and density differences is obtained on the basis of the model of turbulence being non-equilibrium with respect to the momentum moments, and the boundary layer and Boussinesq approximations under the assumption on the Gauss distribution of flow parameters in the radial direction. The system of equations is closed within the framework of the Taylor's hypothesis on the relation between the external radial flow and the axial one in the column. The solution was found numerically. The regimes of the azimuth rotation within the column are revealed, which are caused by the redistribution of the momentum moment between the mean flow and the motion of vortices at an intermediate scale with respect to the column size and the scale of pulsations having a zero mean value of the velocity and moment. P. 499-509

This is a continuation of the study on the gas-dynamic track in a heterogeneous cutting device, which was initiated in [1, 2]. The efficiency parameter for particle acceleration was determined as a ratio of the kinetic energy to energy consumed on particle acceleration. The influence of gas (air and overheated steam) temperature and pressure on intensity and efficiency of particle acceleration was analysed. Recommendations are given about most effective way for creation of heterogeneous flow, which would provide a maximal kinetic energy of particle flux in interaction with the target. P. 511-518

A method is proposed for the computation of gravity flow of a high-concentration granular medium. A model of nonlinearly viscous fluid is used as a granular medium model. A peculiarity of the model for granular medium motion is a more accurate formulation of boundary conditions, which enables us to account for the sliding of particles on rigid surfaces by introducing an empirical coefficient at the determination of vorticity on a wall. The comparison of numerical and experimental data has shown that the consideration of the effect of medium "sliding" on the boundary enables us to describe the granular medium motion with the rheological parameters of the model being close to those of the Newton fluid. The proposed method has been applied for the  analysis of gravity flows in vertical channels in the presence of obstacles of various forms. The prospects for the developed approach at the theoretical investigation of a free-flowing granular medium are confirmed by a comparison with experimental data known in literature. P. 519-528

An implicit finite-difference technique is employed to derive a solution to the flow of an incompressible viscous fluid past an impulsively started semi-infinite vertical plate with uniform heat flux. Transient and steady-state velocity and temperature profiles, the local and average skin-friction and the Nusselt number are shown graphically. The velocity profiles at small values of time t are shown to agree with theoretical solution of the flow past an impulsively started infinite vertical plate with constant heat flux. The effects of different parameters Pr (the Prandtl number) and Gr (the Grashof number) are studied. The stability and the convergence of the implicit finite-difference scheme are established. P. 529-537

Methodical aspects for development of quasi-diffusive methods are presented for calculation of radiant heat transfer in absorbent, emissive and isotropic scattering gray medium in application to generalized statement of the problem. The heat transfer problem can be reduced to solution of approximate differential equations relative to the flux density of volumetric incident (or semispherical resulting) radiation. In turn, these equations can be reduced to differential equations for determination of the flux densities of volumetric and surface incident radiation with given  generalized characteristics of radiation in volume and on boundaries

The effect of the radiant component on the process of heating and evaporation of an oil film in Diesel engine was studied. It was demonstrated that this effect is considerable and cannot be neglected in study of heat and mass transfer in the oil film. The research results explain the experimental phenomena of drastic reduction in oil consumption in engines using fuel-water emulsion. P. 555-560

he technique is proposed to compute the gas flow rate in a plasmatorch by the difference in pressure over the channel length in those cases when it is impossible to define the flow rate with other methods, for example, in a plasmatorch with atmospheric air suction. The results of calculation of stream parameters in the plasmatorch channel for the laminar and turbulent flow regimes are approximated with simple formulas. A method is suggested to estimate a point of the transition from the laminar to turbulent flow with an electric arc, and a relation for critical Reynolds number is obtained. P. 561-567

On the basis of the analysis of global trends, the parameters of power electronic devices and systems are compared; the outlooks and tendencies of the application of different types of devices in power electronic systems are estimated. Application areas are outlined both for the systems and for the devices incorporated in them. The perspectives of structural and electronic circuit developments of power electronic systems are presented, taking account of the properties of devices involved, and specific features of potential consumers of the electric power.