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The paper presents the results of an experimental study of the influence of distributed engines mounted downstream of the trailing edge on the structure of a separated flow around a trapezoidal model of a flying wing in a subsonic wind tunnel. Visualization patterns of the near-wall flow on the leeward side of the model are obtained in the modes of blocked engines and for the rotational speed of the impeller of 32800 rpm in the range of angles of attack of the wing α = 5÷20°. The studies also take into account the location of distributed propulsion relative to the level of the trailing edge, where the axis of rotation of the engine impeller coincided with the continuation of the wing chord line or is higher than that. The possibility of controlling a separated flow by using sources of stationary disturbances in the form of cones and ribs locally mounted at singular points on the wing surface is studied.

The efficiency of fluid atomization by an atomizer is studied as a function of the spray energy. The dependence of the maximum values of energy on the fluid flow rate is analyzed. A linear dependence is obtained for flow rates smaller than 80 g/s, which testifies to a high efficiency of fluid atomization. For flow rates greater than 80 g/s, the droplet energy is seen to decrease drastically, leading to an increase in the spray droplet size, which testified that the atomization quality is deteriorated. This behavior is observed in all regimes considered in the study.

The local flow structure in a turbulent gas-droplet flow behind a single obstacle has been studied numerically for different initial mass concentrations and diameters of dispersed particles. The effect of evaporating droplets flowing around a single square obstacle on the local averaged and pulsating flow structure and the dispersed phase propagation process has been analyzed. The profiles of averaged longitudinal velocity components of the gas and dispersed phases are similar to those for the single-phase flow regime. The gas velocity in the gas-droplet flow is insignificantly (less than 3%) higher than the corresponding value in the single-phase flow. The turbulence kinetic energy increases in approaching the obstacle. Maximum gas-phase turbulence was obtained on an obstacle of height h at x / h = -1÷0, and it is more than 50% higher than the turbulence kinetic energy before and after the obstacle.

An approach is proposed to model hemodynamics in an arteriovenous malformation and its vascular environment during neurosurgical embolization. This approach is based on a combination of the filtration model of blood flow and the embolic agent in the malformation with a hydraulic approach for the vessels surrounding the malformation. The model is described mathematically by a system of integrodifferential hyperbolic equations. The parameters and functions included in the model are determined using real clinical data from patients. Based on the model, the problem of optimal control of multistage embolization was formulated and studied numerically. Optimal embolization regimens were found for which there is good agreement between the calculated and clinical data. The proposed approach can be used to develop preoperative recommendations about the optimal tactics of surgical intervention.

In 1957-1959, according to the program of the 3rd International Geophysical Year, the temperature of rocks (to a depth of 20 m) and glacier ice (to a depth of 45 m) was measured in the area of a high-mountain weather station (glacier no. 31) in the central part of the Suntar-Khayata Ridge (Northeastern Russia). In 2012-2017, the Russian-Japanese expedition carried out new measurements of the temperature of rocks and glacier ice at the same places. A comparison of the data on the mean monthly temperatures of glacier ice at a depth of 10 m in 1958 and 2012 attests to their rise by 1.0-1.6 °С. As there was no possibility to perform direct measurements of rock temperature at a depth of 20 m in 2012 -2017, we used an indirect method to estimate it at the depth of zero annual amplitude. According to our estimate, in the past 60 years, it could have increased by up to 1.6 ° C. Regime studies of the dynamics of seasonal thawing were carried out at four experimental plots; of the dynamics of freezing of the seasonally thawed layer, at one plot .

Results of the study of the regularities of new formation of frozen ground near the southern boundary of permafrost against the background of a positive climate trend are presented. Criteria for the potential formation of permafrost in response to climate warming are established. Results of modeling and quantitative assessment of the newly formed permafrost caused by transformation of landforms during thawing of frozen ground are given with respect to soil drainage and warming effect of the snow cover.

The results of sedimentological analysis of bottom sediments of the Ivashkina Lagoon on the southern coast of Bykovsky Peninsula (southeast of the Laptev Sea) are presented. Core samples from boreholes drilled in the Holocene thermokarst depression now occupied by the lagoon have been analyzed. The use of grain-size distribution data and Passega C-Md diagrams makes it possible to refine the genetic interpretation of the sediments obtained from field descriptions. The Holocene lacustrine-lagoon and taberal formations and the underlying Middle and Late Pleistocene alluvial sediments have been identified, and their grain-size characteristics have been determined. We have further reconstructed the sequence of their formation while a thermokarst depression had been transformed into a lagoon.

The morphology and properties of frozen strata were studied in the area of the largest retrogressive thermal thaw slump Batagay (Yakutia). A presumably continuous stratigraphic sequence of permafrost sediments accumulated during the Middle and Late Pleistocene (~700-11 ka) and was partially transformed during the Holocene. Based on paleopedological, paleontological, and geocryological data, new suggestions have been made regarding the historical development of the soil-vegetation cover and late glacial fauna in the Yana Plateau region. Two extensive and relatively warm climatic periods favoring the formation of developed soil-vegetation cover have been identified: the first one belongs to MIS 15-17 (600-700 ka) or (depending on the dating method) to MIS 7e (230-250 ka); the second one is more certainly dates back to MIS 5e (110-130 ka).

The paper presents the results of studying the appearance and sizes of pockmarks in lakes of three bioclimatic zones of Yamal: northern (arctic), typical, and southern tundra. The diameter of pockmarks in the lakes increases from 1.9 m in the northern tundra to 7.7 m in the southern shrub tundra. Pockmarks occupy from 0.5 to 4.3 % of the shallow-water lake area. The content of methane in lake sediments is two or more times higher than in the sediments of the active and transition layers of dominant landscapes. In the typical tundra zone, the methane content in lake sediments is usually about 7 mL/kg, but in some cases it can reach 18 mL/kg and more. Probably, these are the lakes with the high methane content in bottom sediments, where gas emissions can occur and pockmarks can form. After drainage (drying) of the lakes, lake basins (khasyreys) are subjected to freezing, and the cryogenic structure of lake sediments is formed. Eight-ten years after drying, succession changes in the former lake bottoms continue, and the formation of the transition layer is not yet completed.