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The results of a numerical study of laminar fluid flow and heat transfer in an annular gap between two cylinders with a rib on one of the walls are presented. A mechanism for intensifying heat transfer between two cylinders, when one is rotating, was studied. Intensification was achieved by installing a single rib on the inner or outer cylinder. The rib was oriented along the annular system radius and occupied half the height of the gap between cylinders. The problem was formulated in two dimensions. The Reynolds number was varied in the range from 100 to 1000. Air was the working medium. Four options for the location of the intensifying rib were considered. A fundamental difference in the structure of the recirculation zone was noted for different rib locations. Maximum heat transfer was achieved on the wall of the stationary cylinder opposite the rib mounted on the rotating cylinder. Its multiple increase was observed compared to the case of rotating smooth cylinders.

This paper examines interaction of propagating waves with gas bubbles contained in liquid and the behavior of gas bubbles in a gas-liquid mixture. A description of the experimental setup for studying the influence of a propagating wave on gas bubbles is presented and the observed phenomena are described.

The interaction of longitudinal vortices with a turbulent boundary layer and a mixing layer developing in the diffusion zone was experimentally studied. Vortices were generated using jet vortex generators located near the beginning of the model tail unit, forming a diffusion separation. The main measurements were performed using hot-wire anemometry (HWA) and PIV methods. Based on the experimental data, information was obtained on the flow velocity in the pre-separation and separation zones and the dynamic pressure magnitude; the scale of turbulent structures was calculated, and the influence of longitudinal vortices on these characteristics was estimated under various regimes of vortex generator operation. It was found that the effect of longitudinal vortices on the flow leads to a decrease in the separation zone and significantly affects the characteristic scale of turbulent structures.

Investigation results concerning the influence of fuselage and control surfaces deflection on various types of separation that occur in the flow past a swept-leading-edge wing model at subsonic flow velocities in a wind tunnel are presented. This work continues an experimental series on the study of separated flows and the possibilities of flow control around aircraft wing models at low Reynolds numbers. Using proven methods for visualizing the flow near the wing surface and hot-wire measurements, experimental data were obtained that provide a comprehensive understanding of the separation structures that arise on the leeward side of the wing model at various angles of attack and control surface deflections. The issue of flow separation control is also examined. It is shown that global flow separation can be eliminated using the method of local influence at specific points.

To generate a spray flow in confined spaces, specialized nozzles are required to disperse micron- and submicron-sized droplets at the nozzle edge. High-speed visualization of a gas-droplet flow from a custom-made microchannel nozzle device with a resolution of 2.5 μm/pixel was performed, allowing the sizes of the dispersed droplets to be determined. The nozzle device was a custom-made device with a 243 μm thick microchannel silicon membrane and a microchannel size of 10×10 μm². Measurements of the characteristic dimensions were conducted and the velocities of the dispersed droplets were determined at low liquid flow rates (0.05-2 ml/min) and air pressure differences from 1 to 6 atm. At HFE-7100 flow rate of 1 ml/min and an air pressure differential of 1 atm, the average droplet size was approximately 40 μm, while at a flow rate of 2 ml/min and a pressure differential of 2 atm, the average droplet size was 20 μm. A significant increase in velocity was observed with increasing pressure differential. At the minimum flow rate, very small droplets were dispersed, which were not detected at a resolution of 2.5 μm/pixel, but the overall flow was clearly visible as a "mist."

Using the numerical solution of the Navier-Stokes equations, the development of unstable disturbances and the transition to turbulence in a simulated supersonic jet flowing from a circular supersonic nozzle were studied. The simulation was performed in a three-dimensional formulation with resolution of the vortex structure of the flow. The results of numerical simulations were compared with available experimental data.

The transient effects that develop when supplying fresh air to a ventilated space through a jet oscillator were numerically studied. The results of parametric two-dimensional URANS simulations in the Reynolds number range of (5.3 - 53)×10³ showed that with an increase in the supply flow rate, the frequency of self-oscillations of the supply jet increases linearly, while the Strouhal number varies slightly: from 3.3·10^-3 to 5.4·10^-3. The use of an oscillator intensifies air mixing significantly compared to the basic option with a stationary air supply through a slot, which provides almost uniform temperature distribution in the room during cooling.

The results of hot-wire measurements of periodic controlled disturbances of the mass flow beyond the boundary layer on a flat plate are discussed, and their wave characteristics reflecting the acoustic properties of the supersonic boundary layer are estimated. The possibility of emitting subharmonic disturbances at a Mach number of 2.5 is demonstrated for the first time.

The article considers S.A. Karaganov’s concept of Siberization and the possibilities of using such theoretical tools as V. Christaller’s theory of central places and A. Lösch’s theory of economic landscape for its implementation. It is concluded that a version of the relativistic theory of central places for systems with a dispersed (distributed) main center may be useful for describing and planning urban settlement systems in Asian Russia, which are significantly less mature than those in the European part of the country. In the Far East, it is possible to form a system of central places with a hierarchy corresponding to <i>K</i> = 2. It has been established that settlement development in the post-industrial period should not be treated as a secondary factor in relation to production development, since the standort (location) of modern enterprises should ensure not only reduced costs for energy, raw materials and semi-finished products, as well as proximity to markets, but also advantages in the competition for highly qualified labor. Only a high-quality urban environment can provide these benefits. It is reasonable to expect different patterns of production distribution in the north and in the south of Siberia. In the north, according to Weber, the standort should ensure minimal costs, while in the south, the location according to Lösch will predominate. Such a standort ensures maximum profit. It is shown that even in the most developed regions of Siberia, the location of new high-tech production facilities “according to Weber” is still inevitable. This follows from the continuous nature of territorial development established by B.N. Zimin: each new industry develops it anew. Siberization is being hampered by a serious delay in the implementation of long-discussed railway infrastructure projects: the Barentskomur, the North-Siberian Railway, and the Northern Latitudinal Passage. Only the construction of these railways will significantly increase the cargo-generating base for the ports of the Northern Sea Route. Meanwhile, projects far less urgently needed for the country are being discussed, such as a bridge to Sakhalin and even a tunnel under the Bering Strait.

The article provides a review of publications on the problems of water management activities and riverbed processes under dynamic natural and anthropogenic impacts. Various approaches in this field (ecosystem, basin, and integral ones) are characterized. It is shown that the need to analyze the socio-ecological consequences of water management activities and riverbed processes is currently increasing. Particular importance is given to sociological methods in studying the issues of managing these processes. To illustrate the effectiveness of these methods, the authors present the results of an expert interview and a supporting qualitative in-depth interview with the local population, using the central regions of the Sakha Republic (Yakutia) as an example. The analysis of expert knowledge and public opinion made it possible to identify the main risks and factors of anthropogenic impact on the Lena River, which are most often encountered by specialists and ordinary residents of the region. The main socio-ecological consequences of water management activities and riverbed processes are identified. The strengths and weaknesses of the methods of riverbed process management are formulated. Expert and public opinion on the problems of water management and planning on the Lena River is summarized. It was found that when assessing social consequences, their primary manifestations (human and economic losses) are usually indicated. More complex social processes are mentioned only by some experts and do not have a consistent reproduction of opinions. In general, experts point out that coordination of methods for managing risks caused by riverbed processes should be improved in order to harmonize the activities of various agencies facing relevant problems. It is concluded that, given the weak formalization of the considered ideas and the conflicting interests of various social groups, the use of methods for studying the expert opinions of managers with a supporting public opinion survey proves to be effective.