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This piece of work is concerned with the application of two conventional measuring probes, pressure probe and hot wire, in the wall layer of subsonic ducted, pipe and channel, flows for velocity measurements. Careful measure­ments have been carried out and analysed accordingly for Reynolds number range of 2.8x10⁵≤Re_m≤4.5x10⁵ and 4x10⁴≤Re_m≤2.3x10⁵ for the pipe and the channel, respectively. Pressure probes of outer diameters (d₀⁺= d₀xu_r /ν) 20-120 wall units and hot wire, having wire length (l⁺= l u_τ /ν) of 50-250  for the current Reynolds range, have been utilized to carry out the present measurements. When the pressure probe was applied in the wall layer, the wall proximity and the shear gradient played major roles of its incorrect velocity readings, however, this effect was far from being influencing the hot-wire velocity measured in the overlap region. When the pressure probe results compared to those obtained by the hot wire, the pressure probe's data showed hump in the normalized mean velocity profiles around the wall distances y⁺≤300 and y⁺≤150 for the pipe and the channel, respectively. Available corrections are adopted and applied to the pressure probe data measured, yielding results that are comparable to those of the hot wire and this was also demonstrated by comparing the present results corrected to the so-called the logarithmic velocity profile.

The mixing model was used for analysis of linear kinetic problems of phase tran-sition. The asymmetry of evaporation and condensation, which occurs for intensive processes, remains even for the case of linear approximation. The analytical solution for kinetic jumps of pressure and temperature at the condensed phase surface was obtained: it complies with the results of the classical linear theory. The key result of this study is analytical solution for dependency of pressure jump (condensation) on the temperature factor. This dependence has a minimum near the margin between the abnormal and normal regimes of condensation.

In the present work, the entropy generation due to the heat transfer and fluid friction irreversibility is investigated numerically for a three-dimensional flow induced by rotat-ing and stretching motion of a cylinder. The isothermal boundary conditions are taken into account for the heat transfer analysis. The similarity transformations are utilized to convert the governing partial differential equations to ordinary differential eq-uations. Resulting nonlinear differential equations are solved using a numerical scheme. Expressions for the entropy generation number, the Nusselt number and the Bejan number are obtained and discussed through graphs for various physical parameters. An analysis has been made to compare the heat transfer irreversibility with fluid friction irreversibility using the expression of the Bejan number. It is found that the surface is a durable source of irreversibility and the curvature of cylinder is to enhance the fluid friction irreversibility.

An extensive study was performed to establish correlations between the crystal structure, the grain composition, and the dielectric and thermophysical properties of high-temperature multiferroics of the Bi_1-x Dy_x FeO₃ type (x = 0.05–0.20). It is shown that a trade-off between the macroresponses in the materials is achieved at x = 0.10; this circumstance permits recommendation of the materials for practical use.

Theoretical estimations are made in order to support the possibility of the non-equilibrium carbothermic reduction of magnesium after the plasma treatment of agglomerated particles-decamicron mechano-composites which consist of uniformly mixed reacting nano- and sub-micron insertions of magnesium oxide and soot with the preset stoichiometric composition. Experimental results are presented to confirm the practical attainability of the process.

A three-dimensional problem on the control of furnace temperature during cooling of ceramic products of arbitrary shape with allowance for the constraints on thermal stresses is analyzed. An algorithm for calculating a temperature regime making it possible to avoid the occurrence of fracture and irreversible deformation in the products being cooled is proposed. With the example of cooling of a ceramic holder for a spiral wire, a computational experiment is performed. A temperature regime in which the cooling of the product accomplishes in a certain time without exceeding the admissible values of thermal stresses is identified.

In this paper, the process of convective heat exchange between the cooling air and the cylindrical solid is experimentally studied in a chamber furnace at double-sided cross-flow around the solid, and the corresponding criterial equation is obtained.

Fully developed turbulent pipe flows of power-law fluids are studied by means of direct numerical simulation. Two series of calculations at generalised Reynolds numbers of approximately 10000 and 20000 were carried out. Five different power law indexes n from 0.4 to 1 were considered. The distributions of components of Reynolds stress tensor, averaged viscosity, viscosity fluctuations, and measures of turbulent anisotropy are presented. The friction coefficient predicted by the simulations is in a good agreement with the correlation obtained from experiment. Flows of power-law fluids exhibit stronger anisotropy of the Reynolds stress tensor compared with the flow of Newtonian fluid. The turbulence anisotropy becomes more significant with the decreasing flow index n. An increase in apparent viscosity away from the wall leads to the damping of the wall-normal velocity pulsations. The suppression of the turbulent energy redistribution between the Reynolds stress tensor components observed in the simulations leads to a strong domination of the axial velocity pulsations. The damping of wall-normal velocity pulsations leads to a reduction of the fluctuating transport of momentum from the core toward the wall, which explains the effect of drag reduction.

The algorithm for calculation of dynamic compliance of multilayer coatings was developed. The compliance modulus and phase lag of coating surface motion vs. the current pressure depend on viscoelastic properties of materials, ratio of wavelength to layer thickness l/H, and ratio of wave velocity to propagation velocity of shear vibrations in the base layer V/C_t,2⁰ Dynamic compliance of the two-layer coating consisting of a thick base layer and thin durable outer layer was calculated. The elasticity modulus of the outer layer ranged up to eight values of elastic modulus of the inner layer; the density of the outer layer either remained equal to the density of the inner layer or increased proportionally to the elastic modulus. Depending on  V/C_t,2⁰ two scenarios of compliant coating interaction with the turbulent flow were distinguished: resonant and broadband ones. It is shown that the vibration properties of two-layer coatings can be significantly better than the properties of the monolayer coatings. This makes it possible either to increase the coating strength or to work efficiently at lower velocities.

This paper describes a numerical solution of the bow shock shape ahead of some blunt and sharp axisymmetric noses containing sphere, blunt cone, and sharp cone at steady transonic flow in the Mach number range of 1.01 to 1.2. For validating the results, one sphere and three blunt cones are modeled, and their shock standoff distance is compared with other experimental and numerical studies. The flow over other noses with similar geometric parameters is then solved and compared with each other. In this study, the Reynolds-averaged Navier–Stokes equations are solved using the Spalart–Allmaras turbulence model. The purpose of this study is to determine the shock standoff distance for some blunt and sharp noses at low supersonic free flight speed. The shock standoff distance is determined from the Mach number curve on the symmetry line. The present numerical simulations reach down to M_∞=1.01 a range where it is almost very difficult to set in xperimental
studies. The shock wave locations were found to agree well with previous numerical and experimental studies. Our results are closer to the experimental results compared to other numerical studies. In addition, the results for shock standoff distances over paraboloids in these speed ranges have not been previously published as far as we know.