Showing 50 of 813 papers in Mechanics

VARIABLE PLASTICITY AND ACCUMULATION OF DAMAGEABILITY

Unknown
1969 SovietRxiv: ru-196901.04854

The paper develops a model for elastic-plastic media under variable cyclic loading in which material response depends not only on the number of loadings but also on stress amplitude through an accumulated damage function. Within both deformation theory and a simple flow theory, the author introduces…

Determination of the Law of Turbulent Friction in the Core of a Flow on the Basis of the Principle of Maximum Stability

Unknown
1969 SovietRxiv: ru-196901.00425

This paper applies the principle of maximum stability of averaged turbulent flows to determine the turbulent friction law in the core region of channel flow. Using a generalized Prandtl-Taylor representation with a constant near-axis mixing length, the authors reduce the mean velocity profile to a p…

ON STEADY WAVES OF FINITE AMPLITUDE CAUSED BY PRESSURE PERIODICALLY DISTRIBUTED OVER THE SURFACE OF A FLOW OF A HEAVY FLUID OF FINITE DEPTH

Ya. I. Sekerzh-Zen'kovich
1968 SovietRxiv: ru-196801.99719

This paper studies steady finite-amplitude surface waves in an ideal incompressible heavy fluid of finite depth, generated by a prescribed periodic pressure distribution on the free surface. Using conformal mapping of one wavelength of the flow region to an annulus, Bernoulli’s condition is reduced …

INITIAL THERMOSTRUCTURAL STRESSES

S. D. Volkov, V. P. Stavrov, V. Ya. Dolgikh, V. M. Mendelson
1968 SovietRxiv: ru-196801.94367

A statistical boundary-value problem in thermoelasticity is formulated for a macroscopically homogeneous, quasi-isotropic two-component medium with isotropic constituents and random component distribution described by moment functions. For uniform cooling in the absence of external forces, the autho…

ON DETERMINING HYDRAULIC RESISTANCES DURING THE MOTION OF CLAY SOLUTIONS IN A PIPE WITH A PERMEABLE WALL

A. Kh. Mirzadzhanzade, A. K. Karaev, A. A. Movsumov, U. D. Mamadzhanov, G. T. Gasanov, R. T. Aliev
1968 SovietRxiv: ru-196801.92947

This paper examines hydraulic resistance during the flow of clay solutions in pipes with permeable walls, a condition relevant to borehole annular spaces and not covered by earlier studies of impermeable pipes. The authors discuss why changes in total flow rate and in structural mechanical propertie…

POSTCRITICAL ELASTIC STATES OF A CLOSED SPHERICAL SHELL

A. V. Pogorelov
1968 SovietRxiv: ru-196801.92459

This note examines postcritical elastic equilibrium of a closed spherical shell under external pressure, restricting attention to axisymmetric deformations after loss of stability. Using a variational principle for isometric transformations of the shell middle surface, the deformation is represented…

Calculation of the Diffusion Slip Velocity of a Binary Gas Mixture

Yu. I. Yalamov, I. N. Ivchenko, B. V. Deryagin
1968 SovietRxiv: ru-196801.91797

This paper calculates the diffusion-slip velocity of a binary gas mixture near a solid plane wall when a tangential concentration gradient is present. Unlike earlier treatments that assumed incident molecular distributions in the Knudsen layer remain equal to bulk distributions, the authors solve li…

THE INFLUENCE OF MASS AND AERODYNAMIC ASYMMETRY OF A BODY ON THE CHARACTER OF ITS SPATIAL MOTION

A. A. Shilov
1968 SovietRxiv: ru-196801.87351

This paper analyzes the spatial motion of an axisymmetric body whose center of mass is displaced from the symmetry axis and whose center of mass moves uniformly in a straight line. Using Euler equations with aerodynamic restoring and damping moments, it derives energy and angular momentum relations …

VELOCITY FIELD EXCITED BY WING VIBRATIONS PROPAGATING OVER THE SURFACE AT SUPERSONIC SPEED

E. A. Krasil'shchikova
1968 SovietRxiv: ru-196801.86592

The paper formulates a linearized potential-flow problem for the velocity field generated when small surface vibrations propagate over a finite wing moving rectilinearly in an ideal compressible medium at supersonic speed. Using an integral representation for the solution of the governing hyperbolic…

SLIP OF LIQUIDS IN CAPILLARIES

Corresponding Member of the USSR Academy of Sciences B. V. DERYAGIN, N. N. FEDYAKIN
1968 SovietRxiv: ru-196801.86148

This paper investigates the flow regime of liquids in glass capillaries with radii from 0.01 to 0.1 micrometers, where previously observed capillary uptake rates exceeded Washburn equation predictions. Using measurements of meniscus velocity as functions of distance, pressure, and capillary radius f…

ON THE RELATION BETWEEN ACOUSTIC NOISES AND EROSION IN HYDRODYNAMIC CAVITATION

V. I. Il'ichev, G. N. Kuznetsov
1968 SovietRxiv: ru-196801.85922

This paper examines the relationship between acoustic noise and material erosion in hydrodynamic cavitation, treating both as consequences of bubble distribution, number, and collapse dynamics. The authors analyze published erosion measurements and conduct experiments on cavitation noise generated b…

ON A METHOD FOR SOLVING RELAXATION EQUATIONS

N. B. Maslova
1968 SovietRxiv: ru-196801.85511

This note develops a successive approximation method for nonlinear ordinary differential equations describing relaxation in nonequilibrium gases with internal degrees of freedom. The method rewrites the Cauchy problem as integral equations and normalizes each iterate so that the particle number cons…

LAMÉ PROBLEMS IN THE GRADIENT THEORY OF ELASTICITY

Unknown
1968 SovietRxiv: ru-196801.85424

This paper studies Lamé problems in an isotropic gradient theory of elasticity, where the free energy depends on both strains and strain gradients and the equilibrium equations therefore require additional boundary conditions. For an infinitely long tube and a spherical shell under uniform internal …

ACTION OF AN ACOUSTIC PRESSURE WAVE ON A SHALLOW SPHERICAL SHELL

È. I. Grigolyuk, A. G. Gorshkov
1968 SovietRxiv: ru-196801.83386

This paper analyzes the axisymmetric response of an elastic shallow spherical shell immersed in an ideal compressible fluid to a plane step shock pressure wave. The shell is attached along its circular contour to a rigid spherical screen through an elastic rib, and the formulation combines linear sh…

PARAMETRIC INSTABILITY OF THE SURFACE OF A LIQUID IN A VARIABLE ELECTRIC FIELD

V. A. Briskman, G. F. Shaidurov
1968 SovietRxiv: ru-196801.80517

This paper analyzes the parametric instability of a liquid surface in a homogeneous alternating electric field normal to the interface. Using linear stability theory for a viscous incompressible liquid with a conducting or high-permittivity boundary condition, the authors derive an equation for surf…

INVESTIGATION OF THE GAS-DYNAMIC STABILITY OF A DETONATION WAVE OF ARBITRARY PROFILE

S. K. Aslanov, V. N. Budzirovsky, K. I. Shchelkin
1968 SovietRxiv: ru-196801.77842

This paper examines the gas dynamic stability of plane detonation waves for arbitrary heat release kinetics, motivated by cases where Arrhenius temperature dependence is not an adequate description. The authors propose a stepwise model of the detonation zone, representing it as an initiating shock f…

ON EQUATIONS AND BOUNDARY-VALUE PROBLEMS IN THE THEORY OF TWO-PHASE FILTRATION FLOWS IN A POROUS MEDIUM

Hydraulics
1968 SovietRxiv: ru-196801.76878

This paper reformulates the equations for isothermal two-phase filtration of incompressible immiscible fluids in an inhomogeneous porous medium, including relative permeabilities, capillary pressure, gravity, and density differences. By taking either phase pressure and saturation as unknowns, the au…

WAVE ADIABATS FOR MEDIA WITH AN ARBITRARY EQUATION OF STATE

A. D. Sidorenko
1968 SovietRxiv: ru-196801.75505

This paper studies wave adiabats for gases or liquids with nonconvex, anomalous equations of state, where the usual entropy increase condition is insufficient to select admissible shock states. It proposes stability and continuity requirements, states several theorems on the local structure, monoton…

ON THE ACCURACY OF THE KIRCHHOFF–LOVE HYPOTHESIS IN DETERMINING CRITICAL FORCES IN THE THEORY OF ELASTIC STABILITY

A. N. Guz
1968 SovietRxiv: ru-196801.74268

The paper examines the accuracy of the Kirchhoff-Love hypothesis for calculating critical buckling forces in elastic stability problems. Using three-dimensional linearized equations of the nonlinear theory of elasticity, it analyzes a thick orthotropic plate compressed in one direction and derives a…

A RAREFACTION WAVE AND THE EXPANSION OF A MEDIUM IN A VARIABLE GRAVITATIONAL FIELD

K. Dzhusupov, K. P. Stanyukovich
1968 SovietRxiv: ru-196801.72963

This paper analyzes the one-dimensional unsteady expansion of an ideal gas cloud ejected from a gravitating body, treating the cloud as small enough that its motion can be decomposed into center-of-mass motion and expansion relative to that center. Using gas-dynamic equations with a time-dependent N…

ON THE LENGTH OF THE RELAXATION ZONE OF IONIZATION BEHIND THE FRONT OF A STRONG SHOCK WAVE IN AIR

S. A. Losev, V. A. Polyanskii
1968 SovietRxiv: ru-196801.72767

The paper examines the unexpectedly large length of the nonequilibrium ionization relaxation zone behind strong shock waves in air at velocities near 9 to 10 km/sec. The authors numerically solve coupled kinetic equations for dissociation, nitric oxide chemistry, ionization by heavy particles and el…

INSTABILITY CRITERIA FOR DETONATION WAVES

S. K. Aslanov, V. N. Budzirovsky, K. I. Shchelkin
1968 SovietRxiv: ru-196801.68778

The paper derives sufficient instability criteria for detonation waves using a multistage model of chemical reaction zones. By analyzing the characteristic determinant for perturbations, the authors separate the short relative wavelength case into equations for individual fronts and obtain bounds on…

Measurement of Turbulence in Gas Flows by an Optical Method

N. F. Derevyanko, I. L. Kuznetsov, A. M. Trokhan
1968 SovietRxiv: ru-196801.63123

This paper applies an optical correlation method to measure the longitudinal turbulence component in a cold air jet, extending an approach previously used for plasma flows. A schlieren system observes density-marked flow produced by a heated wire, and signals from two nearby image points are recorde…

ON THE THEORY OF HEATING IN HYPERSONIC FLOW

L. M. Biberman, S. Ya. Bronin
1968 SovietRxiv: ru-196801.56897

This paper examines aerodynamic heating of blunt bodies in hypersonic air flow when radiation transfer is coupled to the gas dynamics rather than treated as a separate postprocessing correction. The authors formulate and solve equations near the stagnation line including viscosity, thermal conductiv…

SUPERSONIC FLUTTER OF THREE-LAYER PLATES

A. I. Smirnov
1968 SovietRxiv: ru-196801.55859

This paper analyzes the supersonic flutter of finite three-layer plates using previously derived elastic equilibrium equations that account for bending stiffness of the load-bearing layers, shear stiffness of the core, inertia, in-plane loads, and aerodynamic loading. Assuming piston-theory aerodyna…

A MATHEMATICAL EXPERIMENT FOR COMPUTING TRANSPORT COEFFICIENTS

V. I. Vlasov, S. L. Gorelov, M. N. Kogan
1968 SovietRxiv: ru-196801.51746

The paper addresses the computation of gas transport coefficients in situations where experimental determination or direct solution of the Boltzmann equation is difficult, especially when molecular internal processes are treated mechanically. It proposes a Monte Carlo mathematical experiment that fo…

High-Rank Moments in a Weakly Rarefied Gas

R. G. Barantsev, I. B. Lutanskaya
1968 SovietRxiv: ru-196801.45703

This paper analyzes high-rank moments of the molecular distribution function in a weakly rarefied gas near local equilibrium. Using a Hermite polynomial expansion and the 56-moment system of equations for small Knudsen numbers, it solves the linearized relations for second, third, fourth, and fifth …

A SPHERICAL CUT IN AN ELASTIC SPACE

L. T. Boiko, V. A. Zyuzin, V. I. Mossakovskii
1968 SovietRxiv: ru-196801.44237

This paper treats an axially symmetric elasticity problem for an infinite elastic space cut along part of a spherical surface. Using Trefftz displacement potentials and analytic functions of a complex variable, the authors derive integral representations for displacements and stresses and reduce the…

THE VELOCITY FIELD EXCITED BY A SHOCK WAVE IMPINGING ON A STATIONARY THIN SYMMETRIC BODY

E. A. Krasil'shchikova
1968 SovietRxiv: ru-196801.41839

This paper analyzes the velocity field generated when a finite-amplitude plane shock wave strikes a stationary thin body symmetric about a plane in an unbounded compressible medium. Under small perturbation and irrotational-flow assumptions, the problem is linearized and formulated for the velocity …

THE INFLUENCE OF GAS-FORMING SUBSTANCES IN THE SOURCE OF AN ELECTRIC EXPLOSION ON THE MOTION OF WEAKLY COHESIVE SOIL

I. L. Zel'manov, O. S. Kolkov, A. M. Tikhomirov, A. F. Shatsukevich
1968 SovietRxiv: ru-196801.40585

This paper examines how gas-forming additives placed at the source of a spark-discharge electric explosion affect wave motion in dry, weakly cohesive sand, and compares the results with chemical explosive tests. Soil mass velocity was measured by an induction method at varying distances, with reduce…

STUDY OF THE PATTERN OF SUPERSONIC SPATIAL FLOW PAST A BODY OF SEGMENTAL SHAPE

V. B. Minostsev, G. F. Telenin, G. P. Tinyakov
1968 SovietRxiv: ru-196801.29901

This paper presents a computational study of supersonic spatial flow at angles of attack around an axisymmetric segmental body approximating a rounded spherical sector. Using previously developed methods for subsonic and supersonic regions, the authors calculate ideal gas flow with adiabatic exponen…

TURBULENT FLUCTUATIONS IN THE VISCOUS SUBLAYER

V. M. Liatcher
1968 SovietRxiv: ru-196801.28901

This paper analyzes turbulent velocity fluctuations in the viscous sublayer near a smooth wall by linearizing the Helmholtz form of the Navier, Stokes equations for an incompressible turbulent flow. Using a two dimensional Fourier transform and assuming a linear mean velocity profile in the near wal…

DIFFERENTIAL EQUATIONS OF FILTRATION OF GAS-CONDENSATE SYSTEMS WITH ACCOUNT OF THE CONDENSATION AND SORPTION PROCESSES

Hydraulics
1968 SovietRxiv: ru-196801.21987

This note formulates differential equations for filtration of gas condensate systems in porous reservoirs while accounting for both liquid condensate formation and sorption processes. Under assumptions of thermodynamic equilibrium, ideal gas behavior, isothermal Darcy flow, immobile condensate below…

THE SECOND APPROXIMATION IN THE THEORY OF ASYMPTOTIC DAMPING OF DISTURBANCES IN A SUPERSONIC FLOW OF A VISCOUS HEAT-CONDUCTING GAS

V. N. Diesperov
1968 SovietRxiv: ru-196801.21915

This paper derives second-approximation equations for the asymptotic damping of small disturbances in axisymmetric flow of a viscous, heat-conducting gas past bodies of revolution, allowing both sonic and supersonic incident speeds. Starting from the continuity, Navier-Stokes, and heat-transfer equa…

DETERMINATION OF THE CORRELATION BETWEEN VELOCITY AND TEMPERATURE PULSATIONS IN A TURBULENT FLOW OF AIR IN A PIPE

M. Kh. Ibragimov, V. I. Subbotin, G. S. Taranov
1968 SovietRxiv: ru-196801.21378

This paper investigates turbulent heat transfer in nonisothermal air flow in a smooth vertical pipe by determining correlations between velocity and temperature pulsations. Experiments at Reynolds number about 32,000 used hot-wire anemometry with varied wire orientation and overheating to measure ve…

COMPUTATION OF ELASTIC CONSTANTS FROM MICROSCOPIC QUANTITIES FOR AN ELASTIC MEDIUM WHOSE ENERGY DEPENDS ON STRAIN GRADIENTS

S. S. Kukushkina
1968 SovietRxiv: ru-196801.18611

This paper derives formulas connecting the coefficients of a generalized elastic energy density, including dependence on strain gradients, with microscopic force constants of a crystal lattice. Starting from the Born model of a simple lattice in the harmonic approximation, the discrete lattice descr…