

Home – Home – Jornals – Journal of Applied Mechanics and Technical Physics 2018 number 4
2018 year, number 4
S. I. Gerasimov^{1,2,3,4}, A. S. Knyazev^{1,2}, D. V. Malyarov^{1,2}, B. A. Yanenko^{2,5}, R. V. Gerasimova^{2,3}, E. S. Khoroshailo^{2}
^{1}AllRussian Research Institute of Experimental Physics, Sarov, Russia, 607190 ^{2}Sarov Physical and Technical Institute, Sarov, Russia, 607186 ^{3}National Research Nuclear University, Moscow, 115409 Russia ^{4}Nizhny Novgorod State Technical University named after R. E. Alekseev, Nizhny Novgorod, Russia, 603950 ^{5}Russian Electrotechnical Institute, Moscow, Russia, 111250
Keywords: противометеоритная стойкость, кумулятивный заряд, компактный элемент, ударное нагружение, взрывное метающее устройство, resistance to meteoroids, cumulative charge, compact element, impact loading, explosive projecting device
Abstract >>
A scheme for obtaining and detecting highvelocity compact metal elements moving with hypersonic velocities under highintensity shock loading is developed. A lightgas ballistic device and shadow photography are used for this purpose. Application of the hemisphere  cylinder cladding makes it possible to test a cumulative charge steadily forming in a compact steel element, moving with a velocity approximately equal to 6 km/s. The results of the numerical and experimental testing of this projecting device are given.

A. A. Vorob'ev
Peter the Great Military Academy of Strategic Missile Forces, Balashikha, Russia, 143900
Keywords: электротермический ускоритель, плазма, ударник, разрядная камера, высоковольтный разряд, electrothermal launcher, plasma, impactor, discharge chamber, highvoltage discharge
Abstract >>
A mathematical model for the interior ballistics of an electrothermal launcher of macrobodies has been developed which can be used to predict the projectile velocity for specified values of the mass and size of the impactor, the electrodynamic parameters of the capacitive energy storage, and launcher parameters. The problem of determining the projectile velocity was solved in a hydrodynamic formulation by numerical integration of the equations of motion, the energy conservation equation, and the caloric equation of state. It is shown that without accounting for the dynamically changing friction coefficient and erosion of the electrodes, the calculation results differ considerably from the experimental data, but the model qualitatively describes the physical processes of interior ballistics of the electrothermal launcher.

Al. F. Gaisin^{1}, N. F. Kashapov^{2}
^{1}Kazan' National Research Technical University named after A. N. Tupolev, Kazan', Russia, 420111 ^{2}Kazan' Federal University, Kazan', Russia, 420021
Keywords: газовый разряд, жидкие электроды, струйнокапельный режим течения, шлиренметод, gas discharge, liquid electrodes, jetdroplet flow, Schlieren technique
Abstract >>
Electrophysical, hydrogasdynamic, and thermal characteristics of a discharge arising between liquid electrodes are considered. Spatial visualization of flow patterns in the gas discharge region is performed by using the Schlieren technique.

V. A. Ivanov, Yu. V. Manilyuk, V. F. Sannikov
Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russia, 299011
Keywords: сейши в бухте, свободные волны, длинные волны, волновые течения, бассейн с открытым входом, аналитические решения, мода Гельмгольца, бухты Севастополя, seiche in a bay, free waves, long waves, wave flows, basin with an open entrance, analytical solutions, Helmholtz's mode, Sevastopol bays
Abstract >>
Twodimensional seiche oscillations in a rectangular basin of constant depth with an open entrance are considered within the framework of the linear theory of long waves. An analytical solution is obtained for the case where a nodal level line is located at the entrance to the basin. It is shown that transverse seiches in a basin with an open entrance are twodimensional in contrast to similar modes in a completely closed basin, which are onedimensional. Calculation of seiche parameters is performed for model basins having dimensions and depth characteristic of a number of Sevastopol bays. Comparison of the results of the calculations are with the data of fullscale observations show that they are in satisfactory agreement.

Sh. Rafiq^{1}, M. Nawaz^{2}, M. Mustahsan^{1}
^{1}The Islamia University of Bahawalpur, Bahawalpur , Pakistan, 63100 ^{2}Institute of Space Technology, Islamabad, Pakistan
Keywords: жидкость Кэссона, некоаксиальное вращение, пористая среда, напряжения сдвига, Casson fluid, noncoaxial rotation, porous medium, shear stress
Abstract >>
The flow of the Casson fluid due to noncoaxial rotation of a disk and the fluid at infinity is investigated. Partial differential equations are made dimensionless and coupled. The exact solution of the resultant nonlinear initialboundaryvalue problem is solved by applying the Laplace transform. The shear stresses at the disk surface and the steady state stresses are computed. The effects of dimensionless parameters on the dimensionless primary and secondary velocities are analyzed.

A. V. Voevodin, A. A. Kornyakov, A. S. Petrov, D. A. Petrov, G. G. Soudakov
Central Aerohydrodynamic Institute named after N. E. Zhukovskii, Zhukovslii, Russia , 140180
Keywords: актуатор, плазма, математическая модель, эксперимент, расчет, эжектор, actuator, plasma, mathematical model, experiment, calculation, ejector
Abstract >>
A new type of ducted pulse thermal actuators with a high pulse repetition frequency is proposed to control wing buffeting at transonic flight velocities. Ducted pulse thermal actuators can operate up to frequencies of about 1 kHz, which is sufficient for controlling the majority of aerodynamic processes at high subsonic flow velocities. As the use of a pulse thermal actuator in the regime of tangential injection of a jet is less efficiency from the energy viewpoint than in the regime of boundary layer suction, an ejectortype pulse thermal actuator is proposed for implementation of the suction regime.

A. G. Petrov
Ishlinskii Institute for Problems in Mechanics, Russian Academy of Sciences, Moscow, Russia, 119526
Keywords: трехосный эллипсоид, течения вязкой жидкости в приближении Стокса, равновесные формы вращающейся жидкости, triaxial ellipsoid, viscous fluid flow in the Stokes approximation, equilibrium shapes of a rotating fluid
Abstract >>
Problems of motion of a triaxial ellipsoid in an ideal fluid and in a viscous fluid in the Stokes approximation and also equilibrium shapes of the rotating gravitating fluid mass are considered. Solutions of these problems expressed via four quadratures depending on four parameters are significantly simplified because they are expressed via the only function of two arguments. The efficiency of the proposed approach is demonstrated by means of analyzing the velocity and pressure fields in an ideal fluid, calculating the attached mass of the ellipsoid, determining the viscous friction, and studying the equilibrium shapes and stability of the rotating gravitating capillary fluid. The pressure on the triaxial ellipsoid surface is expressed via the projection of the normal to the impinging flow velocity. The shape of an ellipsoid that ensures the minimum viscous drag at a constant volume is determined analytically. A simple equation in elementary functions is derived for determining the boundary of the domains of the secular stability of the Maclaurin ellipsoids. An approximate solution of the problem of equilibrium and stability of a rotating droplet is presented in elementary functions. A bifurcation point with nonaxisymmetric equilibrium shapes branching from this point is found.

D. N. Gorelov
Sobolev Institute of the Mathematics, Siberian Branch, Russian Academy of Sciences, Omsk, Russia, 644043
Keywords: сингулярные интегральные уравнения, интеграл Коши, формулы СохоцкогоПлемели, singular integral equations, Cauchy integral, SochockiPlemelj formulas
Abstract >>
Singular integral equations of the first and second kind with the Cauchy kernel on a limiting narrow closed contour are theoretically considered. The initial equations are found to degenerate on the limiting contour. This singularity of integral equations with the Cauchy kernel does not allow boundaryvalue problems of the flow around thin airfoils to be solved correctly; therefore, a system consisting of integral equations of the first and second kind is proposed for solving such problems. The results of the present study are tested against an exact solution of the problem of the flow past a flat plate.

N. A. Khan^{1}, F. Sultan^{2}
^{1}University of Karachi, Karachi 75270, Pakistan ^{2}NED University of Engineering and Technology, Karachi 75270, Pakistan
Keywords: вязкопластическая среда, модель Бингама  Папанастасиу, вращающийся диск, решение Кармана, viscoplastic medium, BinghamPapanastasiou, rotating disk, von Kбrmбn solution
Abstract >>
This study is conducted to investigate the BinghamPapanastasiou fluid flow driven by a rotating infinite disk. The BinghamPapanastasiou model is a modification of the Bingham plastic model, which is developed by introducing a continuation parameter to overcome its discontinuity. The von Kármán similarity solution is used to transform the flow equations from ordinary differential equations to a nonlinear system of partial differential equations, which is solved numerically. The effect of the Bingham flow parameters on the radial, tangential, and axial velocities, pressure, and radial and tangential skin friction coefficients is discussed.

A. V. Kashevarov^{1}, A. L. Stasenko^{1,2}
^{1}Central Aerohydrodynamic Institute named after N. E. Zhukovskii, Zhukovskii, Russia, 140180 ^{2}Moscow Institute of Physics and Technology, Zhukovskii, Russia, 140180
Keywords: обледенение, кристаллы льда, несферические частицы, математическое моделирование, icing, ice crystals, nonspherical particles, mathematical modeling
Abstract >>
The process of airfoil icing caused by incidence of ice crystals is considered. A physicomathematical model of motion of spheroidal crystals in the gas flow and their interaction with the body is formulated. The model takes into account the nonspherical particle orientation with respect to the velocity vector of the gas flow. It is assumed that particle collision with the body surface leads to partial destruction of the particle under the action of normal and tangential stresses, and some part of the particle mass remains in the vicinity of the collision point. An inviscid flow around the airfoil with a timedependent shape is calculated by the method of approximate conformal mapping.

A. A. Shebelova^{1,2}, A. V. Minakov^{1,2}, M. Yu. Chernetskii^{1}, P. A. Strizhak^{3}
^{1}Siberian Federal University, Krasnoyarsk, Russia, 660041 ^{2}Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090 ^{3}National Research Tomsk Polytechnic University, Tomsk, Russia, 634050
Keywords: органоводоугольное топливо, капля, деформация, эксперимент, математическое моделирование, VOFметод, organic watercoal fuel, droplet, deformation, experiment, mathematical modeling, VOF method
Abstract >>
This paper describes an experimental study of deformation of a droplet of an organic watercoal fuel in a gas flow. The experimental data obtained are used to develop a technique that as a basis for a numerical study of integral characteristics of deformation of the droplets of organic watercoal fuel 4.5 mm in diameter with a gas flow velocity of 2 m/s and a temperature of 298 K. The characteristic changes of the area of longitudinal and transverse cross sections of the droplets of the organic watercoal fuel during their gravitational deposition in time are revealed. It is shown that the theoretical and experimental data satisfactorily agree.

A. E. Bukatov, A. A. Bukatov
Marine Hydrophysical Institute, Russian Academy of Sciences, Sevastopol, Russia, 299011
Keywords: колебания плавающей пластины, изгибногравитационные волны, волны конечной амплитуды, взаимодействие волн, floatingplate oscillations, flexuralgravity waves, finite amplitude waves, wave interaction
Abstract >>
Asymptotic decomposition to small quantities of the third order for the velocity potential of a fluid of finite depth and the bending deformations of a floating elastic plate arising from the interaction of harmonics of finiteamplitude progressive surface waves were constructed using the method of many scales. An expression for the secondharmonic amplitude was obtained, and critical values of the wavenumber were determined. Oscillations of the plate for different values of its thickness and elastic modulus were analyzed. Vertical displacements of the plate under bending deformation were studied.

V. P. Danko^{1,2}, S. N. Diyanova^{1}, A. G. Abazyan^{1}
^{1}Kuban State Technological University, Krasnodar, Russia, 350072 ^{2}Plekhanov Russian Economic University, Krasnodar, Russia, 350002
Keywords: гидродинамика, тепломассообменный аппарат, псевдоожиженный слой, холодильная система, кондиционирование воздуха, hydrodynamics, heat and mass exchange devices, fluidized bed, refrigeration system, air conditioning
Abstract >>
Hydrodynamic modes of heat and mass exchange devices with a movable nozzle are considered. Relations for the critical speed, loss of momentum in the working area, and the dynamic thickness of the layer of nozzle elements are obtained which are necessary for engineering calculations.

C. Zhang^{1}, Z. Wang^{2}, J. Kang^{3}
^{1}Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, Tianjin, China, 300384 ^{2}School of Energy and Power Engineering, Jinan, China, 250061 ^{3}School of Electrical and Electronic Engineering, Tianjin, China, 300384
Keywords: газовая турбина, внутреннее охлаждение, продольные ребра, увеличение теплопереноса, gas turbine, internal cooling, longitudinal intersecting ribs, heat transfer augmentation
Abstract >>
This paper describes a detailed numerical investigation of a stationary highaspectratio ribroughed rectangular cooling channel with longitudinal intersecting ribs near the gas turbine blade trailing edge region. In order to overcome the heat transfer performance degeneration in the highaspectratio channel, longitudinal intersecting ribs are arranged on the channel bottom surface. The effect of the number of longitudinal intersecting ribs on the flow and heat transfer is systematically studied in the Reynolds number range Re=1000030000. The results show that a heat transfer augmentation region exists just downstream the junction between the longitudinal rib and the angled rib due to additional secondary flows. With more longitudinal intersecting ribs, the heat transfer distributions on the channel surfaces are more uniform. Though the pressure loss is also enlarged with an increase in the number of longitudinal intersecting ribs, the overall thermal efficiency increases in the entire range of Reynolds numbers investigated. The configuration with two sets of longitudinal intersecting ribs shows the best overall thermal efficiency

A. H. Aghdam, N. Poladvandi
Arak University of Technology, Arak, Iran, 381351177
Keywords: эжектор, первичный и вторичный потоки, уровень шума, ejector, primary and secondary flows, noise
Abstract >>
The aim of this project is implementation of computational fluid dynamics (CFD) for numerical simulation of the ejector flow. Optimal values of the ejector geometry that ensure the maximum ejector performance and the minimum noise level are determined.

V. G. Bazhenov, S. L. Osetrov, D. L. Osetrov
Scientific Research Institute of Mechanics, Nizhny Novgorod, Russia, 603950
Keywords: экспериментальнорасчетный метод, краевой эффект, критерий Консидера, потеря устойчивости пластического деформирования, локализация деформаций, шейка, параметр подобия, experimentalcomputational method, edge effect, Considere criterion, loss of stability of plastic deformation, strain localization, neck, similarity
Abstract >>
Large deformations of elastoplastic cylindrical rods and shells of different thicknesses under tension are studied. The influence of the geometry of the samples and the dependence of stresses on deformations under uniaxial tension on edge effects and the neck formation process are estimated. The applicability of the Considere criterion for determining the instance of stability loss of plastic deformation under tension is analyzed. The computational experiments confirm that the role of similarity in the processes of nonuniform deformation of samples under tension can be played by the ratio of the tangent of the slope of the true strain diagram to the stress intensity.

E. V. Karpov, A. G. Demeshkin
Lavrent’ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090
Keywords: слоистый композит, гибридный композит, текстолит, стеклотекстолит, разрушение, многократное нагружение, layered composite, hybrid composite, textolite, glass, textolite, fracture, multiple loading
Abstract >>
This paper describes an experimental study on strain and fracture of plane samples made of glass textolite and textolite with surface and inner aluminum layers. It is shown that the presence of these layers reduces the strength of glass textolite under static and lowcycle loading. This can be explained by the fact that the stretching of a hybrid composite along the layers is accompanied by the formation of localized tensile regions of glass textolite across the layers. As a result, both the hybrid composite and its glasstextolite component are stratified.

M. A. Legan^{1,2}, A. N. Novoselov^{1}, N. V. Fedorova^{1,2}
^{1}Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia, 630090 ^{2}Novosibirsk State Technical University, Novosibirsk, Russia, 630073
Keywords: стекло, хрупкое разрушение, кольцеобразная трещина, задача Герца, вдавливание шара в упругое полупространство, эксперимент, нелокальные критерии разрушения, glass, brittle fracture, ringshaped crack, Hertz problem, indentation of a ball into an elastic halfspace, experiment, nonlocal fracture criteria
Abstract >>
Results of experiments on indentation of steel balls of various diameters into glass samples shaped as rectangular parallelepipeds are reported. The limiting load of formation of a ringshaped crack near the contact region and the radius of this crack are experimentally determined. The field of the contact stresses in the fracture region is found by using the Huber solution of the Hertz problem of pressing a ball into an elastic halfspace. Modeling fracture caused by contact interaction is based on using the local criterion of the maximum stresses and several nonlocal criteria: criterion of mean stresses, Nuizmer criterion, and gradient criterion. For calculating the parameter that has the length dimension and is included into the nonlocal fracture criteria, the limiting tensile stress and the critical stress intensity factor of glass are experimentally determined for beams without and with a notch. It is demonstrated that the experimental data on the ringshaped crack radius are most adequately predicted by the gradient criterion among all criteria considered in the study. However, this criterion overpredicts the limiting tensile stress in the course of beam bending, which is caused by the scale factor.

A. A. Movchan, S. A. Dumansky
Institute of Applied Mechanics, Russian Academy of Sciences, Moscow, Russia, 125040
Keywords: сплавы с памятью формы, устойчивость, дважды связанная постановка, shape memory alloys, stability, twicecoupled statement
Abstract >>
Problems of the stability of a rod of shape memory alloy during direct martensitic phase transformation under the action of constant compressive loading are solved taking into account the effect of stresses on the phase transition and the effect of the phase transition on the temperature regime using various statements. A comparison of the results of the solutions is made.

V. Sh. Shagapov^{1}, E. V. Galiakbarova^{2}, I. G. Khusainov^{3}, Z. R. Khakimova^{2}
^{1}Mavlyutov Institute of Mechanics, Ufa, Russia, 450054 ^{2}Ufa State Oil Technical University, Ufa, Russia, 450062 ^{3}Bashkir State University, Sterlitamak, Russia, 453103
Keywords: импульс, трубопровод, жидкость, газ, фильтрация, грунт, pulse, pipeline, liquid, gas, filtration, soil
Abstract >>
The dynamics of a pulsed signal propagating in an underground pipeline with a damaged section is investigated. Pressure waves propagating along a linear pipeline filled with a fluid are considered. Due to viscous friction and thermal conductivity, dissipation is taken into account in a thin liquid or gas layer near the wall. It is assumed that the pipeline section with damage is a reflective surface. Conditions on this surfaces were obtained under the assumption that the rate of liquid leakage during wave propagation through the damaged area is determined by the permeability of the soil. It is shown that in weakly permeable soils, the signal does not provide full information on damage, and in wellpermeable soils, only short (highfrequency) pulsed signals can be used to detect damage.

V. N. Paimushin^{1,2}, R. K. Gazizullin^{1}
^{1}Tupoleva Kazan National Research Technical University, Kazan, Russia, 420111 ^{2}Kazan Federal University, Kazan, Russia, 420008
Keywords: тонкая пластина, жесткий каркас, прослойка, ячейка периодичности, преграда, энергопоглощающее покрытие, модель КирхгофаЛява, трансверсальномягкий материал, акустическая среда, частота колебаний, точное аналитическое решение, thin plate, rigid frame, interlayer, periodicity cell, barrier, energyabsorbing coating, KirchhoffLove model
Abstract >>
The problem of the propagation of a stationary acoustic wave through an infinite thin plate stiffened on two sides by a system of absolutely rigid, crossed ribs and between two absolutely rigid barriers. It is assumed that the plate and the ribs evenly distributed along rectangular Cartesian axes are connected through elastic interlayers (foundations) without sliding. The dynamic deformation of the plate is described by the linearized KirchhoffLove equations of the classical theory of plates, the dynamic deformation of the interlayers is described by twodimensional and onedimensional relations based on linear approximations of displacements of points of the coating and interlayers along the thickness and taking into account only transverse compression and transverse shear, and the motion of acoustic media by the wellknown wave equations. The solution of the problem is obtained using the Ritz method. The constructed solution was used to investigate how the physicomechanical and geometric parameters of the mechanical system and the frequency of an acoustic wave incident on the plate influence the sound insulation parameters and the stressstrain state of the plate.

F. S. Latifov^{1}, M. A. Mekhtiev^{2}
^{1}Azerbaijan Architecture and Construction University, Baku, Azerbaijan, AZ 1073 ^{2}Institute of Mathematics and Mechanics, National Academy of Sciences of Azerbaijan, Baku, Azerbaijan, AZ 1141
Keywords: цилиндрическая оболочка, заполнитель, нелинейные параметрические колебания, вариационный принцип, подкрепленная оболочка, cylindrical shell, filler, nonlinear parametric vibrations, variational principle, stiffened shell
Abstract >>
Using the variational principle in a geometrically nonlinear formulation The problem of parametric vibrations of a longitudinally stiffened orthotropic cylindrical shell in contact with an elastic medium and under internal pressure is solved in a geometrically nonlinear formulation using the variational principle. The influence of the external medium is taken into account using the Pasternak model. Amplitudefrequency dependences are constructed for parametric vibrations of a stiffened orthotropic cylindrical shell filled the medium.

I. M. Utyashev^{1}, A. M. Akhtyamov^{1,2}
^{1}Mavlyutov Institute of Mechanics, Russian Academy of Sciences, Ufa, Russia, 450054 ^{2}Bashkir State University, Ufa, Russia, 450076
Keywords: несимметрический потенциал, обратная задача, собственные значения, струна, идентификация, asymmetric potential, inverse problem, eigenvalues, string, identification
Abstract >>
This paper considers the inverse problem of identifying boundary conditions for the problem of vibrations of a string in an elastic external medium, whose elasticity coefficient is described by an asymmetric potential. It is shown that, in contrast to the case of a symmetric potential, the boundary conditions can be uniquely identified, but this requires the use of three, rather than two, vibration eigenfrequencies. Cases are considered in which unique identification using two eigenfrequencies is possible. Methods for determining boundary conditions from two and three eigenfrequencies are proposed. The error of the methods is analyzed.

V. M. Kosenkov
Institute of Pulse Processes and Technologies of the National Academy of Sciences of Ukraine, Mykolaiv, Ukraine, 54018
Keywords: скорость деформации, деформация, разрушение, напряженнодеформированное состояние, листовые высокопрочные стали, strain rate, deformation, fracture, stressstrain state, highstrength sheet steel
Abstract >>
This paper describes an experimental study of the strain rate of DP780, DP980, and T=240 highstrength sheet steels on an increase in their plasticity under uniaxial and biaxial tension. The strain rates of the steels vary in the range from 104 to 17 х 103 s1.

G. V. Kozlov, I. V. Dolbin
KabardinoBalkar State University, Nalchik, Russia, 360004
Keywords: структура нанокомпозита, углеродные нанотрубки, фрактальный анализ, перколяция, модуль упругости, nanocomposite structure, carbon nanotubes, fractal analysis, percolation, elasticity modulus
Abstract >>
Fractal analysis methods are used to construct a model describing the effect of a nanofiller structure (carbon nanotubes) on the structure of a nanocomposite as a whole and its mechanical properties. It is shown that an increase in the fractal dimension of carbon nanotubes, which are ringlike formations in a polymer matrix, or their compaction can increase the elasticity modulus of the nanocomposites. It is determined that a significant effect on the mentioned properties of nanocomposites is produced by the spatial structure of carbon nanotubes.

