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Results of tensile and low-cycle fatigue testing of samples made of an aluminum-lithium alloy of the Al-Mg-Li system obtained by plasma-assisted laser cutting performed by a pulsed CO₂ laser in an argon jet with the laser beam and optical discharge plasma simultaneously affecting the material are reported. Low-cycle fatigue tests show that the number of loading cycles survived by the sample obtained by plasma-assisted laser cutting is more than twice greater than the number of cycles survived by the samples obtained by conventional laser cutting with continuous radiation.

This paper presents a solution of the two-dimensional non-stationary problem of the development of wave motion in a two-layer liquid of finite depth under ice cover modeled by a thin elastic plate taking into account longitudinal compression forces. The cases are considered where, in the unperturbed state, one of the layers is at rest and in the other (top or bottom) layer, the horizontal flow velocity varies linearly in thickness. Dispersion dependences were determined for three wave modes arising in the presence of shear flow. The vertical deflections of the ice cover due to a pulsating source of disturbances located in an initially motionless layer of liquid were calculated. A special case is also considered where the liquid is bounded at the top by a solid lid. The problem is considered in a linear formulation, and the liquid is assumed to be ideal and incompressible.

The influence of the jet pressure ratio ( n =1.18÷3.35) in a nonisobaric supersonic jet of a vibrationally excited gas SF6 exhausting from a convergent axisymmetric nozzle 0.25 mm in diameter is studied numerically and experimentally. The experiments aimed at studying the gas-dynamic structure of the jets are performed in a specially designed jet setup of the Khristianovich Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences. The numerical simulations are performed by solving two-dimensional Navier-Stokes equations within the framework of the ANSYS Fluent software and the thermally perfect gas model. The influence of excitation of vibrational degrees of freedom of the SF6 gas is studied in both an equilibrium gas and vibrationally nonequilibrium gas. The nonequilibrium state of vibrational degrees of freedom is simulated with the use of a two-temperature model of relaxation flows. It is shown that the jet pressure ratio of the SF6 gas affects the length of the wave structure cells, which is responsible for the change in the vibrational relaxation rate. The coefficient of density amplitude reduction in gas-dynamic cells is derived as a function of the jet pressure ratio.

The movement of dissolved salt in melting snow is considered based on the equations of non-isothermal two-phase filtration. The thermal conductivity of snow and dependence of the water freezing temperature on salinity were verified against available experimental data. The influence of the presence of dissolved salt on the phase transition was evaluated by numerical experiments.

The influence of the amplitude of deflectors introduced into a laminar jet flow on the coefficient of linear change in the radial component of a stationary disturbance is investigated. The method for introducing disturbances and the method for measuring them are described. It is shown that a decrease in the amplitude of the deflectors does not lead to a change in the flow pattern, does not prevent the occurrence of an algebraic growth mechanism, and causes a proportional decrease in the radial component of the stationary velocity disturbance. The transition to the turbulent regime occurs after reaching a certain value of the radial expansion, which does not depend on the initial amplitude of the introduced disturbance.

The paper presents the results of an experimental study of the influence of distributed engines mounted downstream of the trailing edge on the structure of a separated flow around a trapezoidal model of a flying wing in a subsonic wind tunnel. Visualization patterns of the near-wall flow on the leeward side of the model are obtained in the modes of blocked engines and for the rotational speed of the impeller of 32800 rpm in the range of angles of attack of the wing α = 5÷20°. The studies also take into account the location of distributed propulsion relative to the level of the trailing edge, where the axis of rotation of the engine impeller coincided with the continuation of the wing chord line or is higher than that. The possibility of controlling a separated flow by using sources of stationary disturbances in the form of cones and ribs locally mounted at singular points on the wing surface is studied.

The efficiency of fluid atomization by an atomizer is studied as a function of the spray energy. The dependence of the maximum values of energy on the fluid flow rate is analyzed. A linear dependence is obtained for flow rates smaller than 80 g/s, which testifies to a high efficiency of fluid atomization. For flow rates greater than 80 g/s, the droplet energy is seen to decrease drastically, leading to an increase in the spray droplet size, which testified that the atomization quality is deteriorated. This behavior is observed in all regimes considered in the study.

The local flow structure in a turbulent gas-droplet flow behind a single obstacle has been studied numerically for different initial mass concentrations and diameters of dispersed particles. The effect of evaporating droplets flowing around a single square obstacle on the local averaged and pulsating flow structure and the dispersed phase propagation process has been analyzed. The profiles of averaged longitudinal velocity components of the gas and dispersed phases are similar to those for the single-phase flow regime. The gas velocity in the gas-droplet flow is insignificantly (less than 3%) higher than the corresponding value in the single-phase flow. The turbulence kinetic energy increases in approaching the obstacle. Maximum gas-phase turbulence was obtained on an obstacle of height h at x / h = -1÷0, and it is more than 50% higher than the turbulence kinetic energy before and after the obstacle.

An approach is proposed to model hemodynamics in an arteriovenous malformation and its vascular environment during neurosurgical embolization. This approach is based on a combination of the filtration model of blood flow and the embolic agent in the malformation with a hydraulic approach for the vessels surrounding the malformation. The model is described mathematically by a system of integrodifferential hyperbolic equations. The parameters and functions included in the model are determined using real clinical data from patients. Based on the model, the problem of optimal control of multistage embolization was formulated and studied numerically. Optimal embolization regimens were found for which there is good agreement between the calculated and clinical data. The proposed approach can be used to develop preoperative recommendations about the optimal tactics of surgical intervention.