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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.

The two-dimensional problem of potential flow around two circular cylinders is considered for given velocity at infinity, circulations around cylinders, and the radii and relative position of the cylinders. Exact analytical formulas for the complex potential and the complex conjugate velocities in terms of the Jacobi theta functions are derived. The circulations around the cylinders are uniquely determined using the Gol'dshtik's minimax principle: the circulations should be selected so that the maximum fluid velocity in the stream is minimal.

The propagation and destruction of nonlinear internal waves in the summer-autumn period at the hydrophysical test site of the Pacific Oceanological Institute, FEB RAS in the shelf zone of the Sea of Japan have been studied for a number of years. By continuous measurement of vertical temperature and velocity distribution at depths of 20-60 m using bottom stations and by a regular study of the distributions of the main hydrodynamic characteristics along selected paths, mechanisms have been determined for the generation and propagation of nonlinear packets of internal waves due to internal tide decay and other short-period sources of thermocline deformation have been detected that can be attributed to the propagation of benthic and surface vortex structures. High spatiotemporal resolution of the temperature field in the neighborhood of bottom stations made it possible to reveal the fine structure of wave perturbations of various types. Multilayer shallow-water models for wave-packet propagation have been developed and verified using the data of full-scale and laboratory experiments.

This paper presents a three-dimensional direct numerical simulation of the chaotic dynamics of the free surface of a dielectric liquid placed in an external tangential electric field. The physical model includes the effects of energy pumping (external force), energy dissipation (viscosity), and surface tension. As the external electric field strength increases, a transition from the turbulence of dispersive capillary waves (at zero field) to anisotropic electrohydrodynamic wave turbulence is observed. In the strong field limit, where the fluid motion becomes highly anisotropic, a cascade of small-scale capillary waves is formed that propagates perpendicular to the external field direction. In this regime of motion, a new turbulence spectrum occurs, which differs from the classical spectrum of capillary turbulence.

The possibility of changing the morphology of the silicon surface at certain parameters of the glow discharge is shown. It has been established that oxidation is the main process influencing the surface morphology during glow discharge plasma treatment. As a result of processing in the investigated range of parameters, various stages of the surface oxidation process are observed: the formation of a uniform oxide layer, the formation of nano- and microstructures of silicon oxide. It is shown that these processes lead to surface modification, which acquires stable hydrophilic and superhydrophilic properties.