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Results of numerical and experimental investigations of the sonic boom parameters for two configurations of civil supersonic transport are presented. Numerical modelling is performed by a combined method based on calculating the spatial flow in the near zone of the aircraft configuration and subsequent determination of disturbed flow parameters at large distances from the examined model. Numerical results are compared with experimental sonic boom parameters measured in the near zone and with results of their recalculation to large distances within the framework of the quasi-linear theory. This validation allows the degree of adequacy of the inviscid Euler model for solving the posed problem to be determined. Reasons for certain disagreement between the calculated and experimental data are discussed. The analysis confirms the possibility of attenuating the sonic boom generated by supersonic transport with an unconventional configuration based on a tandem arrangement of two wings on the fuselage.

The rarefaction effects in the problem of hypersonic flow around a profile with blunted leading edge are studied in the flow regimes when the edge bluntness radius is comparable with the mean free path in the free stream. The flow around a cylindrically blunted thick plate at zero incidence was modelled numerically in the transitional regime by using the direct simulation Monte Carlo method, the finite-difference solution of the kinetic equation of the relaxation type (the ellipsoidal statistical model), and the solution of the Navier ⎯ Stokes equations. It is shown that for the Knudsen numbers in terms of the bluntness radius below 0.1, the Navier ⎯ Stokes equations can be applied successfully for viscous flow description behind the shock wave provided that the initial rarefaction effects are taken into account via the slip and temperature jump boundary conditions on the plate surface. For Knudsen number of about 0.5, the rarefaction effects are more appreciable; in particular, a substantial anisotropy of the distribution function takes place, but the Navier ⎯ Stokes equations yield, as before, a qualitatively correct result. The initial stage of the boundary layer development in the edge vicinity has been studied. In the considered range of Knudsen numbers, the entropy layer near the edge is comparable with the boundary layer thickness. As the distance from the leading edge increases one observes the absorption of the entropy layer by the boundary layer. In the studied parameter range, the interaction between the boundary and entropy layers leads to a flow stability increase

The optic noncontact method of velocity field measurement in the flow volume is considered in this paper for the purposes of hydroaerodynamic experiment. The essence of this method is measurement of particles motion in the flow during short periods between laser pulses. This study offers and implements several algorithmic optimizations, allowing data processing time reduction. It is shown that application of threshold background filtering on the recorded projections (particle images) and fast estimation of initial intensity distribution in the volume allows increasing the speed of tomographic reconstruction algorithm two or three times. Reconstruction accuracy and errors in determination of particle shift were studied in this work using artificial images. The described tomographic method for the velocity field estimation in the flow volume was used for diagnostics of a turbulent submerged jet flowing into a narrow channel. The application of developed approaches in experiment allowed us to obtain spatial distribution of the average velocity field and instantaneous velocity fields in the measurement area.

Influence of elasticity module of coating material on the parameters of hard compliant coatings deformation has been analysed. Calculation using two-dimensional model has shown that maximum coating deformation is achieved at the ratio of flow rate U to the parameter = (E/3ρ)^0.5 approximately equal to 2.5, however, velocity of wall surface motion has first local maximum at ≈ 1. The range of coating parameters' values at which compromise between its hardness and intensity of interaction with turbulent flow is provided has been determined. For rubbery materials with Poisson coefficient of about 0.5, correlations of the flow velocity and parameter shall be in the range 1÷1.5. It is shown that at such parameters, the mean square value of the coating surface deflection/inflection is less than the viscous sublayer thickness, its correlation with the wavelength is very small and equals (1÷5)·10⁻⁴. Such form of deformed surface fundamentally differs from the parameters of the wave wall in Kendall's experiments which results are used for calculation of inverse influence of wall deformation on the flow. It was assumed that solid compliant coatings do not cause instability of interaction with the ambient flow.
Analysis of the coating surface motion rate has shown that its mean square value is 5÷6 % of the value of the dynamic flow velocity at wide change of elasticity modulus of the coating material from 0.01 to 10 MPa. This is proved by the earlier proposed mechanism of drag reduction based on the change of the picture of Reynolds stress generation in the vicinity of the compliant wall. The performed analysis allowed explaining comparatively low drag decrease in the experiments with solid compliant coatings. The valuerealized in these studies was from 0.06 to 0.3 that was much lower than the optimal value.

This article investigates the natural convection flow of viscous incompressible fluid in a channel formed by two infinite vertical parallel plates. Fully developed laminar flow is considered in a vertical channel with steady-periodic temperature regime on the boundaries. The effect of internal heating by viscous dissipation is taken into consideration. Separating the velocity and temperature fields into steady and periodic parts, the resulting second order ordinary differential equations are solved to obtain the expressions for velocity, and temperature. The amplitudes and phases of temperature and velocity are also obtained as well as the rate of heat transfer and the skin friction on the plates. In presence of viscous dissipation, fluids of relatively small Prandtl number has higher temperature than the channel plates and as such, heat is being transferred from the fluid to the plate.

A derivation of the conjugation criterion for a rotating disc is reported. Characteristics of conjugate heat transfer on a single disc and in a cavity formed by two discs, one rotating and the other stationary, are analysed.

The paper presents the results of experimental investigation of heat transfer and hydrodynamics of falling films of binary mixtures of R21 and R114 freons on the surfaces with complex configuration. The vertical tubes of 50-mm diameter with the smooth and structured surfaces, made of D16T alloy, were used as the working sections. The range of film Reynolds number at the inlet to the working section was Re =10÷155. The image of wave surface of the falling liquid film was visualized and recorded by a high-speed digital video camera. At evaporation the heat transfer coefficients on the smooth and structured surfaces are determined by the liquid flow rate and weakly depend on the heat flux. At low liquid flows, the heat transfer coefficients on the structured surface decrease in comparison with the smooth surface because of liquid accumulation and enlargement of efficient thickness in microtexture channels. At high liquid flows, a change in the structure of the wave film surface leads to an increase in heat transfer coefficients in comparison with the smooth surface.

Boiling up of metastable liquid on the surface of a cylindrical heater is studied at high superheating, when the evaporation front is formed. Boiling up begins with formation of a spherical bubble on the heater wall. Evaporation fronts propagating along the heater with the constant velocity are formed due to development of interfacial instability.  The mathematical model describing the growth of a spherical bubble and vapor cavity behind the evaporation front is developed. Results of numerical simulation agree with available experimental data.

High-calcium volatile ash of brown coal from the Berezovsky open-pit mine of the Kansk-Achinsk basin selectively sampled from different points in the ash-collecting installation at BSRES-1 (convective pit, prechamber, and each of the four fields of electrofilters) was studied. Differences between these middlings in chemical composition, dispersity, binding properties were established. The types of volatile ash samples were determined in the system of their chemical classification. It was shown that the ash samples of Beresovsky, Nazarovo coal from the 1^st - 4^th fields of electrofilters differ from all the known kinds of ash by the maximally high calcium content. It follows form the phase diagram of the system СаО-Al₂O₃-SiO₂ that hydraulically active phases similar to the basic phases of the Portland cement clinker may be formed from the ash of electrofilters. Due to differences in the composition of ash samples, the ratio of these phases will be changed, too. Along with differences in particle size, this allows one to obtain Portland cement with special properties on this basis. Six fractions of magnetic microspheres of high purity were obtained; their chemical, quantitative phase composition and morphology were studied, including the contribution from globules of different kinds and the structural texture features of the material; methods of application were determined; the trends of changes in composition and morphology with changes in fraction size were established.