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Journal of Applied Mechanics and Technical Physics

2020 year, number 3

Experimental Study of Three-Dimensional Wave Formation from a Solitary Two-Dimensional Wave on Vertically Falling Liquid Films

A. V. Bobylev, V. V. Guzanov, A. Z. Kvon, S. M. Kharlamov, D. M. Markovich
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: пленка жидкости, уединенная волна, неустойчивость в поперечном направлении, трехмерная волна, лазерно-индуцированная флюоресценция, liquid film, solitary wave, transverse instability, three-dimensional wave, laser-induced fluorescence

Abstract >>
The transformation of a solitary two-dimensional wave into three-dimensional waves on a falling liquid film was studied using the high-speed method of laser-induced fluorescence allowing high spatial and temporal resolution, which allows measuring the thickness of liquid films with high spatial and temporal resolution, the process of decay of a solitary two-dimensional wave into three-dimensional waves in case of film flow along a vertical plate. It was shown that the package of three-dimensional waves resulting from the decay of a solitary two-dimensional wave had a strong perturbing effect on the falling film and leads to the formation of rivulets on its surface.

Burning of Heavy Fuel Oil in a Steam Jet in a New Burner

S. V. Alekseenko, I. S. Anufriev, M. S. Vigriyanov, E. P. Kopyev, I. S. Sadkin, O. V. Sharypov
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: горелочное устройство, мазут, перегретый водяной пар, состав продуктов сгорания, калориметрические измерения, burner, heavy fuel oil, superheated steam, composition of combustion products, calorimetric measurements

Abstract >>
A series of experimental investigations is performed for determining the thermal and environmental characteristics of burning heavy fuel oil of the M-100 type sprayed by a jet of superheated steam in a laboratory prototype of a new burner. A scheme of liquid fuel burning preventing choking of narrow fuel channels of injectors is proposed; this scheme ensures effective burning of high-viscosity fuels and wastes. The process of stable burning of heavy fuel oil in a low-power (7 kW) burner with low concentrations of toxic emissions and high combustion efficiency is realized.

Evolution of Views on the Wave Structure of a Liquid Film in Annular Dispersed Gas-Liquid Flow

A. V. Cherdantsev1,2, D. M. Markovich1,2
1Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Novosibirsk National Research State University, Novosibirsk, 630090 Russia
Keywords: дисперсно-кольцевое течение, волны возмущения, волны ряби, срыв капель, взаимодействие волн, полевые измерения толщины пленки жидкости, метод лазерно-индуцированной флюоресценции, annular dispersed flow, perturbation waves, fluctuation waves, entrainment of droplets, wave interaction, field measurements of liquid film thickness, laser-induced fluorescence

Abstract >>
The wave structure of a liquid film blown by a high-velocity gas flow with entrainment of droplets from the film surface has been investigated. The paper presents an analysis of existing methods of measuring the thickness of the local fluid film and a review of the classical concepts of wave hydrodynamics of annular dispersed flow obtained in early studies using crude methods. A systematic description of the structure, evolution, and interaction of waves of various types is made based on analysis of high-resolution spatio-temporal records of film thickness obtained by laser-induced fluorescence. The results are compared with the results of modern experiments, and the necessity of revising some classical concepts is shown. Directions for further research are suggested.

Vortex Pair of Coaxial Helical Filaments

V. L. Okulov1,2
1Novosibirsk State University, Novosibirsk, 630090 Russia
2Technical University of Denmark, DK-2800 Lyngby, Denmark
Keywords: вихревая динамика, винтовой вихрь, вихревая пара, равновесное вращение, vortex dynamics, helical vortex, vortex pair, equilibrium rotation

Abstract >>
Possible existence of vortex pairs of coaxially rotating helical filaments with circulation in the opposite directions is theoretically studied. Such pairs are generated, e.g., by a rotating blade of the rotor with identical intensities of the tip and shifted axial vortices. Conditions that ensure uniform rotation of the vortex pair of helical filaments are found, which is needed for modeling vortex wakes behind rotor blades.

Coherent Structures and Turbulent Transfer in the Initial Region of Jets and Flame in Swirling Flow

A. S. Lobasov, L. M. Chikishev, V. M. Dulin, D. M. Markovich
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
Keywords: закрученная струя при наличии горения, распад вихревого ядра, когерентные структуры, турбулентный тепломассообмен, swirling in the presence of combustion, vortex core breakdown, coherent structure, turbulent heat and mass transfer

Abstract >>
This paper presents the results of experimental studies of the spatial flow structure and coherent structures in the initial region of swirling jets at a Reynolds number of 5000 and various swirl parameters. The contribution of these structures to the intensity of turbulent transfer of momentum and mass (impurity) was first quantitatively evaluated. In addition, the effect of coherent structures on pulsations of the intensity of local heat release due to the deformation of the flame front during combustion of mixtures of methane at an air excess coefficient of 1.43 was investigated for the case of strong swirling with vortex core breakdown.

Parametric Description of the stationary Helical Vortex in a Hydrodynamic Vortex Chamber

S. I. Shtork1,2, E. S. Gesheva1, P. A. Kuibin1,2, V. L. Okulov2,3, S. V. Alekseenko1
1Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090 Russia
2Novosibirsk State University, Novosibirsk, 630090 Russia
3Technical University of Denmark, DK-2800 Lyngby, Denmark
Keywords: вихревая динамика, винтовой вихрь, вихревая камера, параметрическое описание, vortex dynamics, helical vortex, vortex chamber, parametric description

Abstract >>
A swirling flow in a tangential-type hydrodynamic chamber with stationary vortex structures is experimentally investigated. The main attention is paid to determining the geometric and kinematic parameters necessary for a correct description of helical vortices and their spatial structure, in particular, to testing the possibility of a theoretical description of the limiting case where the vortex becomes stationary, i.e., its rotation frequency (or precession frequency) becomes zero. It is shown that the theory of helical vortices ensures a sufficiently accurate prediction of conditions for the appearance of their stationary (immobile) states.

Experimental Study of the Mixing of Fluid Flows with Different Temperatures in a T-Junction

L. A. Bolshov1, N. A. Pribaturin1,2, O. N. Kashinsky2, P. D. Lobanov2, A. S. Kurdyumov2
1Nuclear Safety Institute, Russian Academy of Sciences, Moscow,115191, Russia
2Kutateladze Institute of Thermophysics Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: тройниковое соединение, смешение потоков, температура, эксперимент, T-junction, flow mixing, temperature, experiment

Abstract >>
This paper presents the results of an experimental study of mixing fluid flows with different temperatures in a T-junction. The experiments were performed with liquids having substantially different physical properties. The distributions of the average and fluctuation temperatures on the surface of the wall of the T-junction and the structure of the temperature fields in the region of mixing of flows of cold and hot liquids were obtained.

Study of Resistance of a Free Nonisothermal Liquid Film in a Gravity Field

O. A. Burmistrova
Lavrent'ev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: свободная жидкая пленка, гидродинамическая устойчивость, вязкая жидкость, термокапиллярный эффект, свободная поверхность, free liquid film, hydrodynamic stability, viscous liquid, thermocapillary effect, free surface

Abstract >>
In a thin-layer approximation, a problem of a free liquid film vertically bounded by solid walls and being under the influence of gravity and thermocapillary forces is considered. A solution in which the film thickness is constant and temperature is a linear function of the longitudinal coordinate is investigated analytically for stability using the matching asymptotic expansions method and numerically using the orthogonalization method for various values of gravitational acceleration. The results obtained analytically and numerically are in good agreement. It is shown that the solution is unstable, but the increment of perturbations is small even under terrestrial gravity.

Hydraulic Flow Instability in a Ranque Tube

M. Kh. Pravdina, I. K. Kabardin, V. I. Polyakova, D. V. Kulikov, V. G. Meledin, V. A. Pavlov, M. R. Gordienko, N. I. Yavorskii
Kutateladze Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: вихревая труба, центробежные волны, кризис течения, гидравлический прыжок, vortex tube, centrifugal waves, flow crisis, hydraulic jump

Abstract >>
The flow in a Ranque tube with a square cross-section channel was studied within the framework of the hydraulic concept of strongly swirling flow with a circulation zone. Using experimental data, it has been found that the flow in the vortex tube satisfies the hydraulic condition of flow crisis: the longitudinal speed becomes equal to the speed of propagation of centrifugal waves at the boundary between the vortex and the circulation zones. It is shown that the temperature change along the flow occurs mainly in the region of the working channel in which the ratio of the longitudinal velocity at the vortex boundary to the propagation velocity of centrifugal waves fluctuates about unity assumption made The existence of a previously unknown mechanism of energy separation due to the presence of hydraulic jumps during the development of internal waves in a Ranque pipe was assumed.

Numerical Study of the Injection of Liquid Sulfur Dioxide in a Porous Layer Saturated with Methane and Water

M. K. Khasanov1, M. V. Stolpovskii2
1Bashkir State University, Sterlitamak, 453103, Russia
2Ufa State Petroleum Technical University, Ufa, 450080, Russia
Keywords: газовые гидраты, фильтрация, диоксид серы, метан, gas hydrates, filtration, sulfur dioxide, methane

Abstract >>
This paper presents the results of numerical simulation of the injection of liquid sulfur dioxide into a porous reservoir accompanied by the formation of sulfur dioxide gas hydrate. The case is considered where the reservoir is initially saturated with methane and water and has a finite length and an impermeable outer boundary. It is shown that at the initial stage, the displacement of methane from the reservoir can occur with or without the formation of methane gas hydrate, depending on the permeability of the porous medium and pressure. It is found that over time, the thermodynamic conditions in the region of methane filtration become close to the formation conditions of methane gas hydrate.

Water Wave Scattering by a Bottom-Standing Thick Rectangular Barrier in the Presence of an Ice Cover

S. Ray1, S. De1, B. N. Mandal2
1University of Calcutta, Kolkata-700009, India
2Indian Statistical Institute, 203 B.T. Road, Kolkata-700108, India
Keywords: рассеивание волн, ледяное покрытие, толстые препятствия, интегральные уравнения, аппроксимация Галеркина, коэффициенты отражения и пропускания, water wave scattering, ice cover, thick barrier, integral equation, Galerkin approximation, reflection and transmission coefficients

Abstract >>
The problem of scattering of a normally incident surface wave train by an obstacle in the form of a thick rectangular vertical bottom-standing barrier submerged in finite-depth water with a free surface is extended here with an ice cover modelled as a thin uniform elastic plate. The problem is reduced to a set of singular integral equations of the first kind. The Galerkin approximation in terms of simple polynomials multiplied by appropriate weight functions whose form is dictated by the behavior of the fluid velocity near the barrier edges is used for solving the integral equations. The reflection and transmission coefficients are obtained numerically, and they are depicted graphically against the wavenumber for various ice cover parameters. It is observed that the barrier thickness plays a significant role in modelling of efficient breakwaters.

Experimental and CFD Simulation Studies on the Free Surface Flow Behavior and Development in a Liquid Metal Windowless Target

W.-F. Yang1,2, W.-P. Deng1, X.-Y. Zhang1,2
1Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
2University of Chinese Academy of Sciences, Beijing, 10049, China
Keywords: ускоряемые системы, жидкий металл, мишени без окон, свободная поверхность, зоны застоя, accelerator driven system, liquid metal, windowless target, free surface, stagnation zone

Abstract >>
A spallation target is one of the key components of the accelerator driven system. A liquid metal windowless target is an advanced type of a spallation target and has great application prospects. In this study, the free surface flow behavior and development in a scaled-down liquid metal windowless target are investigated in experiments and simulations. The experiments are carried out based on a liquid gallium experimental loop. The CFD simulations are performed based on a three-dimensional target model by using ANSYS CFX. The main working parameters of the target are measured through experiments and then set as the boundary conditions for simulations. The simulated values of the free surface height are in good agreement with the experimental data. The free surface height gradually decreases with an increase in the inlet flow rate and with a decrease in the outlet pressure. The simulation results reveal that a flow stagnation zone presenting large eddies and a reverse flow are formed below the outlet of the inner tube.

Influence of the Marangoni Effect on the Emergence of Fluid Rotation in a Thermogravitational Boundary Layer

V. A. Batishchev
South Federal University, Rostov-on-Don, 344090, Russia
Keywords: свободная граница, неоднородная жидкость, пограничный слой, бифуркации, термокапиллярный эффект, вращение, free boundary, nonhomogeneous fluid, boundary layer, bifurcation, thermocapillary effect, rotation

Abstract >>
Steady axisymmetric regimes of the fluid flow in a thermogravitational boundary layer near the free surface with a nonuniform temperature distribution on this boundary are calculated for equations of fluid motion in the Oberbeck-Boussinesq approximation, where the viscosity and thermal diffusivity are small. With due allowance for the thermocapillary effect, it is demonstrated that nonhomogeneous fluid flow regimes with rotation can arise in the boundary layer owing to a bifurcation in the case of local cooling of the free surface, whereas rotation outside this layer is absent.

Diffusiophoresis and Photophoresis of Heated Large Nonvolatile Aerosol Spherical Particles

N. V. Malai1, E. R. Shchukin2, Z. L. Shulimanova3, D. N. Efimtseva1
1National Research University “Belgorod State University”, Belgorod, 308007, Russia
2Joint Institute for High Temperatures, Moscow, 125412, Russia
3Russian University of Transport, Moscow, 127994, Russia
Keywords: диффузио- и фотофорез, нагретые крупные нелетучие сферические частицы, diffusiophoresis and photophoresis, heated large nonvolatile spherical particles

Abstract >>
This paper describes a theoretical study of the steady motion of a large solid nonvolatile aerosol spherical particle, which contains thermal sources within itself, in a concentration gradient of binary gas mixture components. It is assumed that an average particle surface temperature significantly differs from the temperature of the binary gas mixture surrounding it. Equations of gas dynamics are solved taking into account the power-law dependence of the molecular transfer coefficients (viscosity, thermal conductivity, and diffusion) and the density of the gaseous medium on temperature. Under boundary conditions, diffusion and thermal slip are taken into account. Numerical estimates show that the diffusion and photophoretic forces and velocity substantially depend on the average particle surface temperature.

Nonlinear Effects during the Propagation of Perturbations in a Strong Supersonic Interaction

I. I. Lipatov1, V. K. Fam2
1Central Aerohydrodynamic Institute, Zhukovskiy, 140180 Russia
2Moscow Institute of Physics and Technology, Dolgoprudny, 141700 Russia
Keywords: пограничный слой, распространение возмущений, теория сильного вязко-невязкого взаимодействия, нелинейное взаимодействие, boundary layer, perturbation propagation, theory of strong viscous-inviscid interaction, nonlinear interaction

Abstract >>
Nonlinear interaction and energy loss by harmonics of perturbations propagating upstream are investigated. Formation of new harmonics due to nonlinear interaction of harmonics is shown.

Multiple Solutions for an Unsteady Stretching Cylinder

G. D. Tabassum1, A. Mehmood1, M. Usman1, A. Dar2
1International Islamic University, Islamabad, 44000 Pakistan
2University of Kotli, Azad Jammu and Kashmir, Pakistan
Keywords: двойственность решения, растягивающийся цилиндр, неустановившееся вязкое течение, всасывание, впрыскивание, dual solutions, stretching cylinder, unsteady viscous flow, suction, injection

Abstract >>
The current study is devoted to investigating the duality of the solution for an unsteady stretching cylinder flow subjected to wall normal suction. It is demonstrated by using numerical methods that the dual solutions exist for various values of the curvature parameter regardless of the presence or absence of wall suction.

Optimal Design of a Composite Reinforced by Unidirectional Fibers

V. M. Mirsalimov1,2
1Azerbaijan Technical University, Baku, AZ1073, Azerbaijan
2Institute of Mathematics and Mechanics, National Academy of Sciences of Azerbaijan, Baku, AZ1141, Azerbaijan
Keywords: связующее, волокна, трещины, натяг, коэффициенты интенсивности напряжений, минимаксный критерий, binder, fibers, cracks, interference, stress intensity factors, minimax criterion

Abstract >>
On the basis of a minimax criterion and stress intensity factor minimization, the optimal preload is determined for the case of elastic fibers fit into a doubly periodic system of holes in an isotropic elastic binder. A selection criterion is proposed for an interference fit that prevents the fracture of a composite reinforced with unidirectional fibers and ensures optimal stress distribution.

Strengthening of Masonry Walls Produced from Two Different Materials with Steel Fiber-Reinforced Concrete Panels

A. Buyukkaragoz, Y. Kopraman
Gazi University Faculty of Technology Civil Engineering Department, Ankara, 06500 Turkey
Keywords: кладка стен, бетонные панели, укрепление, стальные волокна, прочность на сдвиг, masonry wall, concrete panel, strengthening, steel fibers, shear strength

Abstract >>
The use of steel fiber-reinforced concrete panels to strengthen masonry walls is examined. Within the scope of this study, 18 of a total of 24 specimens are manufactured by using concrete panels containing steel fibers at specific ratios to strengthen hollow brick and clay brick walls, while the remainder serve as reference specimens. The shear strength, deformation and energy consumption capacities are then evaluated for each of the different strengthening methods.

Characteristics of Reinforced Super High-Molecular Polyethylene during its Perforation

A. A. Shtertser, B. S. Zlobin, V. V. Kiselev, S. D. Shemelin, P. A. Bukatnikov
Lavrentyev Institute of Hydrodynamics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, 630090, Russia
Keywords: циклическое ударное прессование, сверхвысокомолекулярный полиэтилен, компакт, армирующие прослойки, пробивание, вязкость, прочность, cyclic shock pressing, ultra-high molecular polyethylene, compact, reinforcing layers, punching, viscosity, strength

Abstract >>
Volumetric samples of pure ultra-high molecular polyethylene and volumetric samples reinforced with metal interlayers (steel grids and perforated titanium plates) are obtained by cyclic shock pressing. Experiments are carried out in which the properties of compacts made of ultra-high molecular polyethylene with and without metal interlayers are studied during perforation by a lead ball (shot) with a diameter of 8 mm flying at a velocity of approximately 370 m/s. The depth of penetration of a fraction into a compact is experimentally determined. To estimate the penetration depth of a spherical body into a polymer, a model is proposed that describes the motion of a ball in this medium.

Acoustic Emission of Rock Salt at Different Rates Uniaxial Strain and under Temperature

V. L. Shkuratnik1, O. S. Kravchenko1, Yu. L. Filimonov2
1National University of Science and Technology “MISiS”, Moscow, 119049, Russia
2OOO “Gazprom Geotekhnologii”, Moscow, 123290, Russia
Keywords: каменная соль, акустическая эмиссия, термобарическое воздействие, стадии деформирования, rock salt, acoustic emission, thermobaric effect, deformation stages

Abstract >>
Acoustic emission activity and longitudinal and volumetric deformations in rock salt samples subjected to uniaxial mechanical loading with a constant strain rate and thermal stress are measured. The features of acoustic emission during deformation under various thermobaric experimental conditions are analyzed. It is shown that, in contrast to the deformation parameters, the change in the activity of acoustic emission at the boundaries of the indicated stages is nonmonotonic in nature, as well as features that make it possible to accurately determine each stage and estimate the elastic and strength properties of the rock salt.

Free Vibrations of Heterogeneous Orthotropic Cylindrical Shells Reinforced by Annular Ribs and Filled by Fluid

F. S. Latifov, M. Z. Yusifov, N. I. Alizade
Azerbaijan University of Architecture and Construction, Baku, AZ1073, Azerbaijan
Keywords: свободные колебания, подкрепленная неоднородная ортотропная цилиндрическая оболочка, жидкость, заполняющая оболочку, free vibrations, reinforced inhomogeneous orthotropic cylindrical shell, fluid filling the shell

Abstract >>
Natural vibrations of heterogeneous orthotropic cylindrical shells reinforced by annular ribs and filled with fluid are studied. Dependences of a frequency response on various geometric and physical parameters of the problem are described.

Experimental Study of Dynamic Strength of Aluminum Oxide Based Fine-Grained Ceramics Obtained by Spark Plasma Sintering

A. M. Bragov, V. N. Chuvil'deev, N. V. Melekhin, M. S. Boldin, V. V. Balandin, A. V. Nokhrin, A. A. Popov
National Research University, Nizhny Novgorod, 603950 Russia
Keywords: оксид алюминия, оксидная керамика, метод искрового плазменного спекания, баллистические испытания, твердость, трещиностойкость, alumina, oxide ceramics, spark plasma sintering, ballistic tests, hardness, crack resistance

Abstract >>
Spark plasma sintering and a standard free sintering method are used to manufacture ceramic plates with a diameter of 30 mm from aluminum oxide powder with a fraction size approximately equal to 3 m. Dynamic strength of the ceramics obtained is studied. Dynamic loading is carried out by a hardened steel impactor. It is shown that energy dissipation in a material obtained using spark plasma sintering is substantially larger than that in a material fabricated using free sintering, which means that it is more resistant to dynamic loads.