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Numerical simulation of the final viscous stage of degeneration of a momentumless turbulent wake behind a sphere in an isotropic turbulent flow is performed using a modified e ~ ε turbulence model. The laws of degeneration are consistent with those for a momentumless turbulent wake at absent turbulent background.

The effect of icing on the kinematic and power parameters of the working element of a wind generator blade was experimentally studied using a modified laser Doppler anemometry method. Arctic conditions were modeled in a specially designed aerodynamic climatic setup based on an optically transparent plexiglass tube with a square cross-section of 200×200 mm with the following parameters: flow velocity of up to 20 m/s, temperature of up to - 20°C, and relative humidity of up to 90%. The flow was saturated with moisture by fine aerosol generators. Aerosol generator flows were optimized using laser Doppler anemometry. The following parameters were measured: flow velocities at distances of up to 400 mm behind the trailing edge of the blade and power characteristics of the blade element subjected to icing. The effect of icing on aerodynamic and power characteristics is shown.

A method and results of calculating a laminar-turbulent flow past a swept wing under a control action generated by a source of blowing or suction from the model surface are presented. Pioneering results on the influence of three-dimensional blowing and suction sources on stability of the boundary layer on a swept wing and distributions of N-factors of various mechanisms of the laminar-turbulent transition aimed at changing its position are obtained by using the LOTRAN 3 software package.

This paper presents the study of permeability of helium through walls of hollow glass silica microspheres, which can be used as membranes for gas flow. The study was performed in a special setup for measuring the kinetic sorption curves for helium at given pressure and temperature. A mathematical model based on a mono-dispersion distribution was used for approximating the experimental data. The data was obtained for the temperature range 21.5 -110.0 °С. The helium permeability of microsphere walls and the activation energy for helium sorption by microspheres were defined for this temperature range.

Constructing models of thermophysical characteristics of polymer composite materials in the curing process is a highly pressing task that is substantiated in this paper. A mathematical model of hot curing of polymer composites based on a thermosetting resin in a mold is presented. Based on experimental temperature dependences of thermophysical characteristics measured under different conditions, modeling dependences of the volume heat capacity and thermal conductivity of fiber, fabric and granular polymer composites on the degree of cure and resin fraction during curing are obtained, with their distinctive feature being the replacement of the properties of a porous reinforcing filler with those of the cured resin in the model. The results of experiments and calculations are presented. The proposed models of thermophysical characteristics increase the accuracy of process modeling and calculation of optimal temperature-time curing cycles.

The study is aimed at clarifying and revealing the basic principles of the effect of superheated steam and its parameters on the content of solid carbon particles (soot) in intermediate and final combustion products when burning liquid hydrocarbon fuel. Using a laboratory atmospheric atomizing burner, it was determined that there is a significant amount of solid carbon particles at the base of the burner flame. When heated air is used instead of steam, an increase in soot content by ~ 75% is observed. The analysis of the flame glow intensity in a narrow ultraviolet band also showed that in air the glow values are ~75% higher than when using superheated steam. At the same time, it has been established that the soot content in the final combustion products is affected only by the parameter of the dynamic impact of a jet, which determines air ejection from the environment both into the gas generation chamber and into the external flame region.

The paper presents the results of experimental studies on the effect of multi-walled carbon nanotubes (MWCNTs) additives on the viscosity and rheological characteristics of drilling emulsions based on mineral oil. The formulations of typical drilling fluids containing 65 % hydrocarbon phase were modified with nanotubes. The mass concentration of nanotubes in emulsion varied from 0.1 to 0.5 %. The formulation and method of preparing stable drilling emulsions with MWCNT additives have been proposed. The rheology of drilling emulsions modified with MWCNTs was studied. The dependency of rheological characteristics on the nanotubes concentration was obtained. In general, MWCNT additives can significantly alter the rheological characteristics of drilling hydrocarbon emulsions at lower concentrations compared to the additives in the form of spherical nanoparticles. This is very important for their practical use in industry. The optimal concentration of MWCNTs for controlling the rheological properties of drilling emulsions is about 0.25 wt. %.

Considering some limitations of various macroscopic chemical reaction models including the total collision energy (TCE) and general collision energy (GCE) models, the new modification is implemented in the DSMC algorithm for numerical simulation of dissociation of the air along the stagnation line and around a typical hypersonic atmospheric blunt body, STS-2 in non-equilibrium conditions and modified model is compared with others conventional models. Since the TCE and GCE models are dependent on some experimental parameters ( A and B at Arrhenius rate of reaction equation). Also, due to lack of accuracy of the quantum kinetics model, modification version of chemical reaction models is presented as hybrid of modified quantum kinetics (MQK) and modified collision energy (MCE) which this method is able to extract A and B parameters without need experimental background. Accuracy of the current applied chemical model for calculation of flow field characteristics is assessed by comparison of their results with other methods (analytical models and available experimental data). The results indicate that the modification of hybrid model with advantages of independency of the empirical parameters gives more accurate results and provides more accurate solution compared to conventional methods without need A and B constant experimental parameters.

The capsule review of the scientific editor for the thematic issue of the Siberian Journal of Forest Science, 2024, number 3 is presented, dedicated to stationary forest studies.

The observed increase in temperature, caused by increasing concentrations of climate-active (greenhouse) gases in the atmosphere, primarily carbon dioxide (CO₂) and methane (CH₄), may be responsible for the projected release of carbon accumulated over millennia in large areas of northern latitudes. The scale and duration of the expected effect remains an open question, due to the sporadic nature of quantitative estimates of carbon flows. The work reflects the current status, directions and main results of long-term instrumental studies of carbon flows in the ecosystems of the middle taiga subzone of Central Siberia, on the basis of the Middle Yenisei experimental station of V. N. Sukachev Institute of Forest, Siberian Branch of the Russian Academy of Sciences (ZOTTO observatory). The dynamics of CO₂ and CH₄ concentrations in the atmosphere from 2009 to 2020 are presented. The values of net ecosystem exchange of CO₂ for forest-swamp complexes are given, indicating that they act as a sink (sink) of atmospheric CO₂. For representative ecosystems, an assessment of soil CO₂ emission fluxes and the seasonal variation in the values of photosynthetic carbon assimilation by dominants of the subordinate vegetation layer are presented. The patterns of behavior of dissolved forms of carbon in the waters of streams draining oligotrophic and eutrophic swamps in the study area were revealed, and the values of CO₂ emission from the water surface were presented.