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We experimentally investigate the perforation of wire mesh screens by an aluminum projectile over a range of impact angles. The study focuses on the fragmentation mechanism driven by the penetration of mesh wires into the projectile material. A series of hypervelocity impact tests on thin mesh screens reveal the following: as shockwave-induced fragmentation diminishes and the impact angle increases, the projectile undergoes fragmentation primarily via the wire penetration mechanism. We assess the performance of a mesh screen as a protective layer at various impact angles, comparing its effectiveness to that of a solid bumper shield. Additionally, the ballistic characteristics of the resulting fragment cloud are determined.

We experimentally investigate the distributed receptivity of a laminar swept-wing boundary layer to unsteady freestream vortices with streamwise-aligned vorticity in the presence of spanwise-uniform surface waviness. Experiments were performed on a 25° swept-wing model in a well-controlled disturbance environment. We demonstrate that unsteady longitudinal vortices can very efficiently excite-in a distributed manner along the streamwise direction-unsteady crossflow instability modes at specific combination transverse wavenumbers. This excitation results from the scattering of the vortices by the surface inhomogeneities. The present paper (Part 1 of this study) is devoted to describing the experimental approach and its theoretical background, the mean flow structure, the experimental evidence of the high efficiency of this receptivity mechanism, and the experimental verification and critical role of the streamwise wavenumber resonance. Part 2 of this investigation focuses on the experimental determination of the amplitude and phase of the distributed vortex-roughness receptivity coefficients as functions of disturbance frequency and transverse wavenumber. In Part 2, we also determine the receptivity coefficients responsible for exciting crossflow instability waves on a smooth surface and present a comparative assessment of the relative efficiencies of these two distinct mechanisms.

We present a numerical study of the transmission of a shock-wave pulse from a gas into a porous medium saturated with a bubbly liquid. The process is modeled for one-dimensional planar motion under the assumption of a viscoelastic porous skeleton. We examine the dynamics of a shock pulse propagating within a porous medium saturated with a gas-liquid mixture, considering the cases where the skeletal matrix consists of either sandstone or unconsolidated sand. The analysis focuses on the influence of both the shock pulse parameters and the properties of the gas-liquid mixture on the wave dynamics.

We investigate the generation of disturbances in a supersonic wind-tunnel flow by a two-dimensional surface roughness element located on the test section wall. The study focuses on the case where the roughness height is small relative to the thickness of the on-wall turbulent boundary layer. The investigation combines numerical simulations, which resolve the turbulent boundary layer, and experimental measurements using hot-wire anemometry. We examine the effects of the roughness height and width, as well as the flow Mach number, on the generated flow disturbances. The results show that the presence of the two-dimensional roughness induces a stationary N-wave disturbance in the freestream, accompanied by a region of elevated unsteady fluctuations across a broad spectrum. An increase in roughness height is shown to amplify the disturbance amplitude and enlarge its spatial scale. For small roughness widths, the freestream disturbance maintains an N-wave profile. As the width increases, the disturbance amplitude remains constant, but the N-wave bifurcates into two distinct shock waves. Finally, we compare the spatial scales of the mean-flow disturbance for a fixed roughness geometry at Mach numbers of 2.0 and 2.5.

We present a numerical study of a submerged round jet at a low Reynolds number, subjected to harmonic disturbances from two sources positioned at opposite lateral boundaries near the inlet section. Our results demonstrate that, for a specific combination of control parameters, the flow undergoes bifurcation, splitting into two distinct branches-a phenomenon also observed in various other experimental and computational studies involving different types of acoustic and mechanical disturbances. The time-averaged flow velocity fields are computed. The effect of the disturbance amplitude on the jet behavior is investigated, and a critical amplitude threshold, above which flow splitting occurs, is identified.

We present the results of an experimental investigation into heat transfer within the flow duct of a supersonic wind tunnel during tests with solid-fuel combustion products containing a minor fraction of condensed particles. Static pressure and heat flux density distributions along the duct are measured using an array of 29 heat flux sensors and 25 pressure transducers. The design of the heat flux sensors and the key aspects of their implementation are described. Suitable scaling parameters for non-dimensionalizing the experimental data are proposed. Based on the processed and compiled heat flux and pressure distributions, a conceptual model is developed to describe the flow processes inside the supersonic diffuser channel. The primary factors governing the thermal loads on the diffuser structure are identified.

We develop a continuum-based physical and mathematical model to investigate coating growth in the cold gas dynamic spray (cold spray) process. The model accounts for collisions between feedstock powder particles and the substrate (or deposited coating) surface across a range of impact angles. Simulations of coating deposition onto a substrate with a wavy surface topography, using a nozzle translating at a constant velocity, reveal distinct deposition conditions on the descending and ascending slopes of the substrate. Further simulations incorporating forward and backward nozzle tilt angles relative to the translation direction identify an optimal impact angle that maximizes the resulting coating thickness, corresponding to peak deposition efficiency.

We investigate the process of conveying bulk materials within the channel of a dual-mass tubular vibratory elevator, operating in an inclined (elevating) configuration. Using construction sand as the test medium, we analyze the influence of the oscillation frequency and amplitude of the conveying elements, the channel wall inclination angle, and the bulk fill density on both the maximum achievable lift height and the material transport velocity. Our findings indicate that the operating frequency should be carefully detuned from the resonant frequency of the system to ensure stable performance. The most effective control parameters are identified as the oscillation amplitude of the conveying elements and the inclination angle of the elevator relative to the horizontal. Finally, we propose recommendations for refining the process model and suggest directions for future research.

We present an experimental study of internal wave focusing generated by the horizontal oscillations of a toroidal body in a linearly stratified fluid. The cross section of the body is circular, while the curve connecting the centers of these cross sections is elliptical, defining a torus-like shape. For the case of an axisymmetric oscillating torus, the measured amplitude distribution of internal waves in its vicinity is compared with predictions from linear theory under the thin-body approximation. We show that wave generation by non-axisymmetric radiators leads to a reduction in the wave amplitude within the focal zone, attributable to differences in both the total radiated power and the spatial structure of the focusing region. Finally, we construct isosurfaces of the experimentally measured wave amplitudes in the focusing zone and compare these data with results derived from ray theory.

The article is devoted to the generalization of the results of scientific research on topical issues of personnel development in a modern organization in the context of Russian and foreign discourse. The purpose of this publication is to expand and deepen the understanding of the basic concepts of personnel development through a critical assessment of its existing imperatives. The results of the study made it possible to update the basic concept of personnel development in the following areas: the impact of the globalization of the labor market and increased competition between organizations for leadership in the economic space on the strategic vision and integration of personnel development with the overall business strategy of the organization, the dialectical unity and interpenetration of complementary processes of its diversification and inclusiveness, the perception of differences in human resources as a core object and organizational culture of development.