Using an optical method for measuring the velocity fields Particle Image Velocimetry (PIV) and a statistical method for analyzing coherent structures in turbulent flows Proper Orthogonal Decomposition (POD), an experimental study of the spatial structure of large-scale velocity fluctuations in the precavitational and cavitational flow past a circular cylinder with a Reynolds number of 280 000 was carried out.

The paper presents the results of analytical and experimental study of the bleed coefficient at high flight Mach numbers from 3 to 7. For the calculation, an analytical model was used model with a fixed exit in the supercritical bleed mode, which allows varying the bleed air mass depending on flow conditions and parameter bleed system. The measurement of the bleed flow coefficients were performed for three bleed configurations in a wind tunnel at local Mach numbers in front of the bleed area from 2.5 to 5.96. The model had a long forebody, so that before the bleed area there was a thick boundary layer. As a result, new experimental data on bleed coefficient and its general dependence on the Mach numbers up to 6 and the bleed angles of 90 and 45° were obtained. It is revealed that at increase in the local Mach number, the tendency is observed towards a decrease in the bleed coefficient, and this tendency intensifies with decrease in the bleed channel inclination. These data were used to evaluate known analytical models to determine the characteristics of bleed systems at hypersonic flow velocity analytical models to determine the characteristics of bleed systems at hypersonic flow velocity.

Experimental investigation of the influence of the distributed heavy gas (sulfur hexafluoride, SF6) injection into the near-wall sub-layer of a boundary layer) on the hydrodynamic stability in relation to controlled disturbances of the supersonic flat-plate boundary-layer at free-stream Mach number M = 2 have been performed. It was for the first time in controlled experiments obtained that injection of this foreign gas leads to the boundary-layer stabilization that is manifested in reduction of disturbance amplification rates. Good quantitative agreement of collected experimental data with computations based on the linear stability theory is obtained.

Results of experimental studies of the round hydrogen microjet interaction with a coaxial air for supersonic speed jets efflux are presented in this work. It is shown that interaction of round and coaxial air jets at their supersonic efflux leads to appearance of a train small/large-scale and, on the contrary, large/small-scale supersonic cells on a resultant jet with growth and reduction of speed of its efflux, respectively. It is found that the result of the round and coaxial air jets interaction at their supersonic efflux does not depend on geometrical parameters of a round and coaxial exit nozzle.

Results of experimental studies of the round air microjet interaction with a coaxial hydrogen jet at its combustion for supersonic speed jets efflux are presented in this work. It is revealed that combustion of the coaxial hydrogen jet with growth of its speed efflux is accompanied by all scenarios, observed at study of the round and plane hydrogen microjets diffusion combustion. However, “bottleneck flame region” undergoes considerable geometrical deformations because of specifics of a flame of a coaxial jet. It is shown that “bottleneck flame region” is transformed from Y-shaped to spherical shape in the activity of growth of a coaxial jet speed efflux. It is found that a round air microjet interaction with a coaxial hydrogen jet at its combustion is accompanied by several new phenomena: existence of cone-shaped area a coaxial jet combustion near a nozzle exit; existence of small-scale supersonic cells on a resultant flame; absence of the hydrogen combustion efflux from combustion region of a coaxial jet near nozzle exit; flame-out from combustion region of a coaxial jet near nozzle exit that leads to hydrogen ignition downstream, its intensive combustion and sharp acoustic noise occurrence; existence of a turbulent flame, to its separation from a nozzle exit and transition to supersonic combustion of a resultant jet.

The effect addition of inert (He, N₂, Ar, CO₂) and reacting (СН₄, O₂, CF₃Br, (CH₃O)3PO) gases in a hydrogen or in coflowing air stream on lift-off diffusion flame conditions of hydrogen micro jet effluxed from the round micro nozzle was experimentally studied. Using the schlieren technique a critical hydrogen flow rate was established at which the flame of the hydrogen microjet detaches from the nozzle when introducing additives of the studied gases into both air and hydrogen. It has been established that the addition of all the studied gases to the hydrogen leads to a decrease in the velocity range of its microjet at which flame stabilization is possible, regardless of whether the gases introduced into hydrogen are inert or reactive. It is shown that in the case of the addition of various gases to the hydrogen, the main factor determining the critical flow rate at flame lift-off from the micro nozzle is the average molecular weight of the H2 gas mixture with additives. At addition of the studied gases into the coflowing air, the critical flow rate of H₂ is determined by their affect on the chemical reactions of hydrogen oxidation (inhibition effectiveness), as well as by a decrease in oxygen concentration due to dilution of air by additives. The data obtained are of interest to hydrogen energy in terms of determining the limits of sustainable combustion of the hydrogen microjet, as well as determining the minimum phlegmatizing concentrations of additives of inhibitors and fire suppressant in the air, preventing the ignition and explosion of hydrogen in case of emergency at its leak.

Macro- and trace elements variation limits in the blue honeysuckle leaves, collected in the geochemically contrasting environments in the Altai Mountains, were determined by X-ray fluorescence analysis using synchrotron radiation, and their relationship with plant secondary metabolism analyzed. In content of main classes of biologically active plant phenols were found in habitats with increased Ca and Sr contents, resulting in decreased soil K/Ca ratio. The same habitats were found to have increased Cu/Zn and Fe/Zn ratios and decreased Fe/Cu and Fe/Ni ratios.

A study has been first made on the element composition of both the plants of six species, belonging to three families, growing in the Mountain Altai, and the samples of soil from their habitat using the method of X-ray fluorescence analysis, involving synchrotron radiation (SRXRF). The highest accumulation of macro- and microelements is typical of the representatives of Caragana of the Fabaceae family, the lowest content was recorded for the representatives of Potentilla and Sibiraea of the Rosaceae family. The amount of elements - Br, Y, Mo, Nb, Zr, Ti, Rb, Co, Sr, Fe, Ni and V varies within a wide range (С_max/C_min > 5), Mn, Cu and Pb - within small (1,5 ≤С_max/C_min ≤ 2,5) and with very small (С_max/C_min ≤ 1.5) range.

The method of X-ray fluorescence analysis involving synchrotron radiation (SR XRAF) is used to determine the element composition of soil and plants Hemerocallis hybrida hort., growing in the places of different pollution level in the Novosibirsk Oblast. It has been established that the main element pollutants of a technogenic environment, accumulated in excess concentrations in plant leaves and rhizomes are lead, nickel, iron, titanium, and chromium. The SR XRF method provides the reliable data on the content of 20 micro- and macroelements of the plants Hemerocallis hybrida , in the various industrial and transport conditions of pollution.