The development of localized perturbations in the supersonic boundary layer for Mach number M = 2 is numerically investigated. It is found that the leading edge velocity is greater than the trailing edge velocity, which is in agreement with the experimental data. In the leading front oscillations occur as the wave packet moves downstream and their amplitude increases in time. To compare the numerical simulation results with classical stability theory, the wave packet was decomposed into a spectrum on frequencies and wave numbers. The maximum contribution to the total perturbation belongs to waves with angles of inclination of the wave front to the plate leading edge equal to about 60 degrees. Their spatial amplification rate agree well with the data of the stability theory of locally nonparallel flows. The agreement deteriorates at smaller inclination angles due to their smallness relative to the contribution of waves with angles of 60 degrees and the nonlinear interaction with waves of different frequencies, and inclinations.

Within the framework of this work the concept of using a special system as a bearing surface of new types of aircraft is presented. The concept is based on the use of the varioform-sectional wing (VFS wing) device developed and patented by the authors. This bearing surface consists of a rigid bearing frame and with flexible force elements and elastic cladding. On the one hand, the design of the device allows you to organize the control as a current on the surface of the wing due to what significantly improves aerodynamic performance in the area of critical angles of attack. On the other hand, the system allows to control the deflection of the vehicle trajectory by changing the pressure distribution on the carrier surface. In this case, the aircraft does not need classical articulated-section steering elements and associated drive systems and units. This publication demonstrates theoretical and experimental data confirming the effectiveness of the proposed methods.

The paper presents results of experimental investigation on the stability of the supersonic boundary layer in relation to natural disturbances of the first vorticity mode. The surface of the flat plate model was equipped with grooves (slots, rectangular elongated cavities) of small depth and various angles of their orientation 0 and 60°. Wind tunnel experiments have been performed at Mach number 2. It was found that with decrease of orientation angle from 60° to 0 the maximum spatial amplification rate of disturbances is also decreased. For zero angle this growth rate becomes smaller in comparison with a smooth plate. The obtained results show that the first mode disturbances in supersonic boundary layer can be stabilized by streamwise grooves of a small depth. However, presence of surface grooves of the same depth with orientation angle 60° leads to noticeable flow destabilization.

The work is devoted to preliminary studies of the membrane-sorption method of gas separation in the dynamic mode. To study and analyze this gas separation mode, it is necessary to create a special experimental stand and measuring equipment that allows obtaining information on changes in the concentration of components in the gas mixture directly during the experiment. To measure the concentration during the experiment, a concentration sensor for binary gas mixtures developed at ITAM SB RAS based on the hot-wire anemometric method was used. The concentration sensor was tested and calibration dependencies for the air-helium mixture were obtained, a technique for measuring the concentration of components in the gas mixture directly during the experiment was developed. The response time of the sensor to a step change in the helium concentration in the mixture was less than 0.4 seconds. Experiments were conducted to model the dynamic sorption mode during the flow of a helium-containing mixture through a selectively permeable layer of silica microspheres. Based on the experiment results, recommendations were given for preparing a stand for dynamic gas separation based on the membrane-sorption method.

An experimental study of the diffusion plume during the hydrogen flow from a round and slotted micro nozzle at pre- and supersonic velocity has been carried out. Four scenarios of diffusion combustion of a planar hydrogen microjet, including combustion at supersonic hydrogen jet outflow, are found for the first time. It was found that the stabilization of the plume at subsonic hydrogen microjet velocity is associated with the presence of a plume “drag” separating the laminar and turbulent parts of the plume. At supersonic velocity of the underexpanded microjet, the plume stabilization is promoted by the wave structure of inhomogeneities formed. The hysteresis of the diffusion combustion process of a flat hydrogen microjet has been found depending on the ignition region. At ignition near the nozzle cutoff, a connected plume accompanied by nozzle heating is realized. At ignition higher up the jet, a raised flare is realized, with heating of the nozzle cutoff being much less than in the previous case. With increasing flow velocity, the development of the two types of flares proceeds according to different scenarios.

This article presents a study of the influence of external treatment such as: annealing in a furnace, grinding, argon and electron beam welding on the magnetic permeability of austenitic stainless steel. The process of measuring and determining the magnetic properties of steel is described in detail. In addition, the need for additional processing of stainless steel to change its magnetic properties was shown. 

 This paper presents the results of a study of the photophysical activity for products of slow thermal decomposition of energetic material 3-nitro-4,5-dihydro-1,2,4-triazole-5-one (NTO). The spectral properties, color palette, and photoluminescence of NTO decomposition products are shown. It has been found that with an increase in the irradiation wave length from 400 to 700 nm, the output of photons with lower energy increases.

The solution of equations containing an unknown under the integral sign with the help of computer mathematics systems is considered. A rational solution of the equation in the problem of determining impurities by means of laser sensing of the atmosphere is proposed. It is shown how to numerically determine the energy spectrum of quantum systems in the quasi-classical approximation using the Bohr-Sommerfeld quantization condition. Solutions of equations containing Bessel functions in integral representation in the following problems are given: about diffraction of light on opaque disk, about diffusion of magnetic field in hollow cylinder, about determination of critical size of nuclear reactor. The spectrum of Rydberg states of hydrogen atom in electric field is found. A method for determining the thermodynamic properties of relativistic fermi-gas is proposed.