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Based on the volume-of-fluid (VOF) multiphase model and the fluid-structure interaction (FSI) model, combined with the overset grid technology of the STAR-CCM+ software, a computational model for the oblique entry of truncated projectiles into water is established. The hydrodynamic characteristics and structural response characteristics of the projectile for various water entry angles are calculated and analyzed, and the evolution law of cavitation is determined. The numerical results are found to be in good agreement with experimental data

The parameters of the plasma generated by an arc discharge in gaseous helium at pressures of 3, 25, and 50 torr are studied experimentally and theoretically. The properties and orphology of synthesized soot are investigated by methods of the X-ray diffraction analysis, thermogravimetry, and transmission electron microscopy. A theoretical model is used to predict the radial distribution of the gas temperature, which is consistent with the results of thermocouple measurements. It is demonstrated that a change in the pressure in the arc discharge alters the residence time of carbon vapor in various temperature regions. This fact ensures different conditions of formation of carbon nanostructures and allows obtaining soot with essentially different structural and physical properties.

The influence of sinusoidal pulsations of the flow rate of the dispersed phase on the flow characteristics of immiscible high-viscosity liquids in a T-shaped microchannel has been studied. The flow regimes in the unperturbed flow and in the flow subjected to external perturbations with different frequencies and amplitudes were visualized. A dimensionless complex is proposed that describes the transition from parallel to plug flow due to external pulsations for a fixed capillarity number of the carrier phase. The application of perturbations to the plug flow regime is found to lead to flow stabilization and to a reduction in the spread of values of the generated plugs at a frequency equal to the natural frequency of plug separation in the unperturbed flow. The average length of the plugs and the spread of its values are shown to increase with decreasing perturbation frequency.

The atomization of metastable superheated water injected into the atmosphere from a convergent-divergent nozzle at a temperature of 240-260 °С was studied experimentally. The dispersion composition of the spray jet has a bimodal character with a predominance of submicron droplets, whose proportion increases with increasing temperature and reaches 80% at the nozzle outlet at a water temperature of 260 °С. The influence of droplet coagulation on the distribution of the proportion of large droplets along the length of the spray jet was estimated.

A numerical and experimental study of the influence of viscous and capillary forces on the characteristics of multiphase flow in the pore doublet model, which is one of the most well-known elementary models of the pore space, has been carried out. The OpenFOAM platform was used for numerical simulation. A multiparametric analysis of the process of oil displacement by various agents in the pore doublet model was carried out with varying values of the wettability of the pore surface, pressure drop, surface tension coefficient, and the ratio of the sizes of the channels of the pore doublet. It is shown that the obtained results of numerical simulation are in good agreement with the experimental data for the pore doublet model in the case of a hydrophobic surface at various values of the capillary number. The physical model of the pore doublet is implemented in a microfluidic chip fabricated using the soft lithography method. The proposed numerical-experimental microfluidic approach makes it possible to carry out a numerical study of two-phase filtration in models of a porous medium corresponding to laboratory studies, as well as to scale the results obtained by the characteristic core sizes.

The paper presents the results of studying the dynamics of a wave signal as it passes through gas-vapor bubble "screens" in a liquid, taking into account heat and mass transfer at the interface in the acoustic approximation. On the basis of numerical calculations using the fast Fourier transform method, wave patterns for pressure impulses are obtained and the influence of various parameters of the state of a liquid with vapor-gas bubbles on the reflection and transmission of acoustic waves through the “curtain” is studied.

Interface dynamics between immiscible liquids with a large difference in viscosities is experimentally studied by varying the frequency and amplitude of oscillations, the relative initial position of the liquids, and the thickness of the working liquid layer. It is shown that with an increase in the amplitude of the interface oscillations, a finger-like instability, which has a local character, manifests itself in a threshold manner on its surface. The found instability of the oscillating boundary is similar to the Suffman-Taylor instability, which develops when a viscous fluid is uniformly displaced from a slot channel (porous medium).

The classical two-dimensional Cauchy-Poisson problem for an ocean modelled as an incompressible fluid with an elastic bottom is considered here. In accordance with the linear theory, the problem is formulated as an initial-value problem for the velocity potential in the fluid region, dilation potential, and rotational potential in the elastic medium below the fluid region. The Laplace transform in time and the Hankel transform in space are used in the mathematical analysis to obtain the form of the free surface depression and ocean bed vertical displacement component in terms of multiple infinite integrals. These integrals are evaluated asymptotically by the method of steepest descent. Variation of the ratio of the ocean bed amplitude to the free surface amplitude for different forms of the prescribed initial axially symmetric surface depression or the impulse for different values of elasticity parameters is investigated. The results obtained in the study are compared to the analytical solution of the problem in the case with a rigid bottom.

DNS and RANS computation results for flows in two-dimensional channels with bumps are processed to generate input and output data for a machine learning method aimed to enhance the Reynolds stress anisotropy model and, thus, improve the RANS approach accuracy. The tensor basis random forest method is chosen as a machine learning tool. The prediction of the new model for the Reynolds stress anisotropy tensor is in better agreement with DNS data for two channel flow geometries than those obtained by the conventional linear eddy viscosity model.

Implementation of the Candler model of vibrational-vibrational energy transfer between diatomic molecules in an inelastic collision is discussed. An example of oxygen O₂ and nitrogen N₂ interaction is used to analyze the method of simple iterations, the Newton method, the method of bisection, and the approximate formula for calculating the equilibrium vibrational temperature, which is necessary in the Candler model. The method recommended for simulations is the Newton method or bisection. The model of vibrational-vibrational energy transfer is tested by examples of zero-dimensional vibrational relaxation, the flow around a cylinder, and the flow in a wedge-shaped nozzle. It is demonstrated that vibrational-vibrational energy transfer affects the distribution of vibrational temperatures