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This paper describes how the method of preparing a composite TiC - n Ni mixture (n = 40, 50, 75% is the volume fraction of nickel) affects the carbide content in the coating material obtained by cold spraying. It is shown that, when coatings are obtained from a powder mixture prepared in a V-shaped mixer, the titanium carbide content is lower than in coatings obtained from powders mechanically processed in a high-energy planetary mill. In the case of mixing the powder mixture in a V-shaped mixer, fine titanium carbide particles do not reach the substrate surface during spraying because they are decelerated in a shock-compressed gas layer when a supersonic jet accumulates on an obstacle. Thus, these particles do not participate in the formation of the coating. Spraying a mechanically treated powder consisting of composite agglomerated TiC-Ni particles allows for a significant (approximately 1.8-fold) increase in the carbide content in the coating

The impact of vibrating manipulation on arterial hemodynamics and mechanical properties is explored by using the finite element method for the fluid-structure interaction. Numerical simulation results show that massage greatly changes the flow behavior of blood within the artery. Under the massage manipulation, the mean blood flow increases by more than 5.34% at a frequency of 2ʄ₀ and by smaller values at frequencies of f0 and 4ʄ₀. The blood flow has obvious disorder characteristics and an obvious wall shear stress concentration in the mixed flow area. The von Mises stress of the artery wall increases, reaching a peak value at the maximum deformation.

This paper describes an approach to modeling the flow velocity distribution at the inlet of a hydro turbine draft tube that can significantly reduce test costs. The flow is modeled using a special apparatus consisting of a combination of two swirlers: fixed and rotating. A previously proposed method for designing swirlers to generate velocity fields corresponding to the velocity distributions behind real hydro turbines was used to design eight blade arrays modeling the velocity distributions in optimal operating modes of hydro turbines of various types. This paper presents a test numerical calculation of flow parameters using the Ansys program and a comparison of the designed velocity distributions with experimental velocity profiles obtained on an aerodynamic rig using a laser Doppler anemometer. The design, calculated, and experimental velocity profiles at the draft tube inlet are in satisfactory agreement. Thus, the promising approach to the experimental modeling of the hydro turbine flow was successfully tested.

Results of experimental and numerical investigations of the flow around an elongated axisymmetric body or revolution in a low-velocity wind tunnel with a closed test section and in a free flow are reported. The Reynolds number based on the body length is varied in the interval 2,75x10⁶ ÷ 9,40x10⁶. The problem is solved numerically under the assumption of an axisymmetric steady incompressible flow with the use of the ANSYS Fluent software. It is demonstrated that the test section walls produce a significant effect on the flow character and aerodynamic characteristics of the body of revolution for the case where the blockage FACTOR of the test section by the body of revolution is formally within 2%.

New analytical solutions for the calculation temperature changes in the liquid flow and in the metal casing string due to induction heating of the string section. The solutions are based on a one-dimensional analytical model, in which convective heat transfer by fluid flow is taken into account, heat transfer between the liquid and the casing string, heat generation in the metal column when the inductor is turned on and losses in cement and rock due to thermal conductivity. To obtain a solution, the integral method was used. Laplace transform in time, inverse transform carried out using the numerical Stefest algorithm. Features explored temperature field during heating and after shutdown inductor, it is shown that the rate of decrease in temperature anomalies increases with increasing liquid flow in the column. Comparison of the results of calculations by the analytical model with numerical simulation results in the Ansys software package Fluent, as well as with experimental data. It is shown that the received analytical solutions can be used in forecasting temperature anomalies caused by induction heating of the casing columns.

The properties of the dispersion relations for two new fully nonlinear weakly dispersive shallow water models are studied, for which, with certain parameters, it is possible to obtain the fourth, sixth, or eighth order of accuracy of the approximation of the phase velocity of the three-dimensional potential current model. For the hierarchy of shallow water models, under the assumption of a slightly changing shape of the bottom, formulas are obtained that establish the relationship between the rate of change in the wave amplitude and the rate of change in the thickness of the liquid layer, and the dependences of the amplitude and length of the incident wave on the depth of the water area are also derived. It is shown that the new model of the fourth order long-wavelength approximation with the eighth order of accuracy of the dispersion relation provides the best approximation of the considered characteristics in the case of both a horizontal bottom and a variable-shaped bottom

A system of the Euler equations that describe two-dimensional steady flows of an ideal fluid is considered. This system is reduced to a nonlinear Laplace equation for the stream function. With the use of the Hirota τ-function, solutions of three elliptical equations (sin-Gordon, sinh-Gordon, and Titeica equations) are found. A simple method of deriving solutions in the form of rational expressions in elliptical functions is proposed. The resultant solutions describe sources in a swirled fluid, jet flows, chains of sources and sinks, and vortex structures. It is shown that the fluid flow rate over a closed curve is quantized in the case of the elliptical sin-Gordon equation.

Based on the turbulence model and the Ffowcs Williams-Hawkings (FW-H) acoustic model, numerical simulations of acoustic characteristics in the Hartmann whistle with the Helmholtz resonator are carried out. The important parameters that control the flow oscillation features of the Hartmann whistle are the stand-off distance, cavity geometry, nozzle pressure ratio, etc. The computational results are compared to experimental data. Under the condition that the jet exit diameter, cavity diameter, nozzle pressure ratio, and stand-off distance remain constant, the mass flow rate and the sound pressure level are calculated as functions of the diameter and length of the Helmholtz resonator. The results show that the sound directivity is similar in the conventional Hartmann whistle and the Hartmann whistle with the Helmholtz resonator, while the sound intensity is higher in the conventional Hartmann whistle. Also, the sound intensity reaches the maximum in the direction perpendicular to the jet. The magnitude of the sound intensity decreases gradually with an increase in the diameter of the Helmholtz resonator, and the decreasing trend in the fundamental resonance frequency is clearly visible. Next, as the length of the Helmholtz resonator increases, the sound intensity first decreases and then increases again. The effect of the resonator length on the fundamental resonance frequency is not large as compared to the resonator diameter.

The microstructure, surface quality, and thermal shielding properties of the coatings prepared by the methods of magnetron sputtering and electroplating are studied. The results show that the Cr-Ag coating prepared by means of magnetron sputtering is smoother, its porosity and emissivity are lower, and the hardness is higher than that of the coating prepared by means of electroplating.

An algorithm for solving an inverse problem of shaping of a ribbed panel made of the AK4-1 alloy (analog of the AA2018 and Al-Cu₂-Mg₂-Ni₁ alloys) at a temperature of 200 °С is proposed. The problem is reduced to solving auxiliary direct problems on the stress-strain states of the elements of the panel structure. The structural elements are taken to be T-beams subjected to pure bending. The resultant moment for obtaining a desired shape is calculated by the Nelder-Mead optimization method. Two methods of obtaining target-shaped articles are considered: deformation under the plastic flow condition and under the creep condition. The material models used in the study take into account the difference in the mechanical properties under tension and compression, as well as the presence of accumulated damage in the material. The calculations are performed with allowance for elastic spring unloading of the article after load removal.