ISSN: 2949-401X

VOL. 1, NO, 3, 2023

Oct 24, 2023
Dynamics of shock waves in media with longitudinal stratification (to refine evolution)

Bogdanov A. N

An analytical dependence of the velocity of propagation of a plane shock wave on the distribution of density and temperature ahead of its front has been obtained for the case of a one-dimensional geometry of an inhomogeneity arranged in the direction of propagation of the wave under study. The resulting dependence has no restrictions on the intensity of the shock wave in question. A method is proposed for calculating the change in the intensity of the shock wave as it passes through the stratification layer. The role of local, integral and nonlinear effects is shown.

Bulat P. V., Volkov K. N., Dudnikov S. Yu., Prodan N. V., Chernyshov P. S.

The flow around thick airfoils at low Reynolds numbers and the possibility of using methods to control these flow parameters, increasing lift and reducing drag are considered. The calculations are based on a series of propulsion airfoils obtained via a combination of solving the inverse problem of aerodynamics and stochastic methods of global optimization. The calculations take account of a transition from laminar to turbulent conditions, which affects the lift and drag of the airfoil. The applicability of various turbulence models for simulating flow around an airfoil at low Reynolds numbers is discussed. The results of the above calculation make it possible to determine the lift coefficient dependence on the angle of attack and the air flow taken from the airfoil surface optimal for each angle. The results of numerical simulation are compared with the physical experimental data, allowing us to draw conclusions about the accuracy of various turbulence models.

Isaev S. A., Nikushchenko E. A., Iunakov L. P.

The article discusses verification of the MSST-model 2003 with correction for streamline curvature according to the Rodi – Leschziner – Isaev approach (RLI) for separated flow and heat transfer in a narrow channel with a conical dimple located on a heated wall with a slope angle of 45°. The numerical predictions of the integral and local characteristics obtained with standard and modified MSST were compared. The standard MSST 1993 and the RLI-corrected MSST 2003 were found to be superior.

Kotsko P. A., Lemeshonok T. Yu., Sizova A. A.

The paper deals with the possibility of using a neural network to find the aerodynamic characteristics of moving objects. An assessment of neural network application in the field of unmanned aircraft aerodynamics is provided, the advantages of using neural networks compared to traditional methods of calculating aerodynamic characteristics are indicated. A neural network model based on the linear regression algorithm was compiled and trained. With the help of this model, the drag coefficient of a car has been calculated. Simulation results are presented.

Khakimov A. G.

The hypersonic gas flow around a soft cylindrical shell is studied. The pressure on the surface of an inextensible shell is determined by Newton’s theory. The aim of the paper is to determine the shape of the shell, the pressure distribution over the surface of the soft shell, drag force, and drag coefficient. With an increase in the velocity pressure, the shell is stretched along the flow. Deformation of the shell causes a decrease in pressure at points far from the axis of symmetry. Taking into account the ave¬rage pressure leads to a decrease in: the front profile of the shell, the pressure on the shell surface, and the ratio of the resistance coefficient of the soft shell to the resistance coefficient of the round cylinder.

Andryushkin A. Yu., Butsikin E. B., Li ZhenNing

The urgent problem of ensuring acceptable manufacturability of a lightweight part can be solved by choosing a rational method for obtaining and machining the workpiece. When designing aerospace items, topological optimization is used to minimize the weight of parts, which lightens the original part by removing volumes of material from its lightly loaded areas without noticeable loss of strength and rigidity. After topological optimization, the part has a complex shape, which significantly reduces its manufacturability. Traditional and alternative technological approaches to the production of topologically optimized light-weight parts are proposed. The traditional approach is implemented through the extensive machining of a complex-shaped casting. An alternative approach applies minimum amount of machining of the workpiece obtained by selective laser melting in an additive installation. Minimized part weight is provided by an alter-native approach that is costeffective for one-off and small-scale production.

Nilov A. S., Galinskaya O. O., Krasnov V. I.

The paper analyzes the experience of practical use of additive technology methods for obtaining fibrous-reinforced (dispersed carbon and ceramic fibers, whiskers) ceramic matrix composite materials (CMC). The main methods for obtaining such CMC based on additive technologies are considered, their main features, advantages and disadvantages are analyzed, ways of improving the methods for obtaining products from CMC within the framework of these technologies are shown. It is noted that these 3D technologies can be used to obtain various types of machine-building products from fiber-reinforced CMC, operating under high mechanical and thermal loads, exposed to aggressive and radiation media, abrasive wear.

Remshev E. Yu., Kostina M. V., Vorobyova G. А., Kudryashov A. E., Afimyin G. O., Remsheva A. E.

Austenitic steels alloyed with nitrogen are a new structural and multifunctional material, significantly superior to traditional ones in terms of their range of properties, saving Ni and Mo, and capable of meeting the requirements for modern high-duty products. This article studies just this kind of steel Kh21AG16N8MFL with 0.5 % nitrogen, cast type, high-strength and corrosion-resistant (developed by IMMS RAS). Cast steel is characterized by segregation heterogeneity of the chemical composition and the texture of coarse-grained metal; its structure may be porous. However, the main method of processing used for cast steel is heat treatment. The article compares the mechanical properties, structure, and phase composition of samples of this steel after traditional heat treatment (high-temperature annealing and hardening) and aeroacoustic treatment at room temperature in different modes, developed at Baltic State Technical University “VOENMEH”. A positive effect of aeroacoustic treatment has been revealed to ensure consistently high strength of cast steel while maintaining good ductility. The proven application of cold isostatic pressing, used for powder materials to reduce porosity, in combination with the latter treatment does not improve the structure and properties.

Tyapchenko Yu. A.

In the USSR, a large number of modifications of manned spacecraft (MS) “Vostok”, “Voskhod”, “Soyuz”, orbital station modules were created, and projects were developed. To account for these, more than a hundred modifications of information display systems (IDS) have appeared, which are presented in the article in the form of five generations. In each generation, the basic representative crew panels are identified, their appearance is shown, a brief description is given, and their features are noted. Basic IDSs are: “Vostok”, “Voskhod-3”, “Soyuz 7K”, “Soyuz T” and “Soyuz TMA”. A decisive contribution to the creation of MS IDS was made by the Specialized Experimental Design Bureau of the Flight Research Institute named after M. M. Gromov directed by S. G. Darevsky.

Chernikov D. G., Yusupov R. Yu., Pesotsky V. I., Alekhina V. K.

The main features of the formation of assembly joints from dissimilar materials as a result of magnetic-pulse treatment, as well as the main factors affecting their quality, are described. Various designs of assembly joints and process flow diagrams for their production due to the formation of interference and by plastic deformation of one of the parts are considered. Examples of real part assemblies obtained using the technology under consideration, and the results of their various tests are given.