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Investigations (mainly those performed by the authors) of air blowing through a perforated section on a body of revolution with a large aspect ratio in an axisymmetric incompressible flow are summarized. Result of numerical and experimental studies of the flow properties, efficiency of the turbulent boundary layer control and prospects of using it for a body of revolution at small subsonic velocities equivalent to the take-off and landing regimes for a modern subsonic cargo aircraft are analyzed.

Optimization of tangential jet blowing on the upper surface of a supercritical transonic airfoil in the buffet mode was carried out. Two-dimensional Unsteady Reynolds Averaged Navier-Stokes equations were solved to simulate the flow past the airfoil. The Spalart-Almaras turbulence model was used to close the equations. The position of the slot nozzle and the intensity of the jet blowing out of it were varied. The optimal position for blowing with the minimum jet intensity to suppress buffet was determined.

This paper presents the results of a study of the influence of various sources of magnetic field on the size of droplets formed in microfluidic flows. Direct and reverse emulsions in a microfluidic device with flow focusing were obtained using magnetic fluids based on oil and water which are a continuous phase. Non-magnetic inclusions of various volumes were formed depending on the selected parameters: continuous phase flow rate, magnetic field configuration, and the position of the magnet relative to the axis of the device.

A periodic flow of an incompressible fluid around plates at large Reynolds numbers and small Keleghan-Carpenter numbers is considered. The energy dissipation over the oscillation period and the resistance coefficients of the plates are determined. Two-dimensional problems are studied on translational and angular vibrations of a flat plate and a plate in the shape of a circular arc, on translational vibrations of a circular cylinder with ribs symmetrically located on it, on angular vibrations of cruciform plates, as well as the problem of periodic flow around an inclined edge on a flat wall. A three-dimensional problem of translational and angular vibrations of a thin circular disk is considered. All obtained dependences for energy dissipation and drag coefficients are presented in analytical form through velocity intensity coefficients, which characterize the velocity singularity at the sharp edges of the plates with a potential flow around an ideal fluid. Some obtained dependencies are compared with the available numerical and experimental data.

A problem of mathematical modeling of a section of a fuel element (fuel element), including a number of fuel pellets and a shell fragment, in an axisymmetric formulation is considered. It is assumed that the shell is a thermoelastic-plastic body, and the tablet is a thermoelastic body, taking into account the cracking of the material. To numerically simulate the thermal and mechanical contact of tablets with each other and with the shell, various variants of the domain decomposition method were used. The results of calculations are presented, which describe the achievement of the nominal power of a section containing 10 pellets, the influence of cracking of pellets on the thermomechanical state of the fuel rod is assessed.

The feasibility of joining of the 6061 aluminum alloy to double-layer oxygen-free copper (TU1) by laser welding technology is reported. The weld formation and microstructure of the Cu-Cu-Al welding joint for various technological parameters are analyzed. The assessment of experimental results is based on macro- and microstructure observations of the weld using the AxioObserver D1M and Gemini SEM 300 scanning electron microscopes. The width and depth of the molten pool and the mechanical properties of the Cu-Cu-Al welding joint are tested by the Eagle-MD semi-automatic image measuring instrument and the YH-9002 computerized tension and compression machine. Among the nine tested samples, the most favorable weld parameters values are obtained with a laser power at 1600 W and a welding speed of 90 mm/s. The aluminum side area has a richer metallographic structure than the copper side area after welding.

Various crossovers of the effective permeability of certain analytically treatable models of the Darcy flow in porous media are studied. They account for the critical behavior as well for the regimes with low concentrations of obstacles. Transverse permeability of spatially periodic arrays of impenetrable cylinders is found in an analytical form and accounts for various asymptotic regimes. Longitudinal permeability for a square array of cylinders is found as well. Transverse flows past hexagonal and square arrays of cylinders are also considered based on expansions for small concentrations and lubrication approximation for high concentrations of cylinders. Three-dimensional periodic arrays of spherical obstacles are considered as well. Formulas for the drag force exerted by various lattices of obstacles are derived from low-concentration expansions. The Stokes flow through two-dimensional and three-dimensional channels enclosed by two wavy walls is studied by means of expansions for small waviness amplitudes. Compact formulas for permeability are derived in the form of factor approximants for arbitrary values of waviness. Various power laws are accounted for in the regime of large waviness parameters, as well as the existing expansions at small amplitudes.

The classical time-harmonic plane strain problem for a fluid-loaded cylindrical elastic shell is revisited. The results of the low-frequency asymptotic analysis, including explicit formulae for eigenfrequencies, are presented. A refined version of the semi-membrane shell theory is formulated. It is shown that the shell inertia does not affect significantly the lowest eigenfrequencies. It is also demonstrated that the ring stress component has a parabolic linear variation.

The effective thermal characteristics of composite materials used in the theory of solid-state cooling are studied. Two classes of composites are considered: layered structures consisting of a large number of nano-sized layers and two-phase granular composites. It is assumed that the boundaries between media are imperfect. At these boundaries, the temperature experiences a Kapitsa jump. The effective characteristics of layered structures are obtained using the matrix averaging method. The Averaging of the characteristics of granular composites is based on the Bruggeman approach. Formulas taking into account the influence of the Kapitsa interlayer resistance on the average thermal characteristics of the structure are obtained. Expressions for average values of heat sources are derived.

The calculation of the Earth’s insolation with high spatial and temporal resolution made it possible to calculate solar characteristics reflecting changes in astronomical factors regulating variations in incoming solar radiation and changes in the intensity of radiative heat transfer (meridional, in the ocean-mainland system, and interhemispheric). Following this, the astronomical theory of climate change has been modernized on the Holocene scale. Based on the synchronization of global climatic events with extremes of solar characteristics in the Holocene and Late Pleistocene, a method of solar geochronology is proposed, which makes it possible to clarify the chronology of global climatic events and explain their origin.