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This paper analyzes a corrected gyrocompass in which an astatized gyroscope is mounted on a horizontally stabilized platform and brought to the meridian by applied correcting torques. Equations of precessional motion are derived for a moving vehicle on the rotating Earth, and a torque law using meas…
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This paper studies the dynamic stability and flutter of a thin three-layer straight circular conical shell supported at its ends, with a rigid transverse-shear-resistant core and exposed to external potential supersonic flow. Using linear piston theory for aerodynamic pressure and shallow-shell equa…
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The paper examines plastic flow in a thin layer compressed between elastic bodies, where pressure in the layer is coupled to elastic displacements of the bounding surfaces through Green’s functions. It formulates the governing problem as a system consisting of a nonlinear first order pressure equati…
Academician A. Yu. ISHLINSKY
This paper examines why two-axis gyroscopic stabilizers may exhibit lower stability and greater tendency toward self-oscillation than comparable single-axis stabilizers. Under simplifying assumptions including a fixed base, no suspension friction, rigid elements, and a direct-current stabilizing mot…
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A variational formulation is developed for optimizing a one-dimensional magnetohydrodynamic generator with ideal gas flow, neglecting induced magnetic field, viscosity, and heat conduction. Using the principle of minimum integral entropy production, combined with a volume constraint, the paper deriv…
V. P. Korobeinikov
This paper develops a numerical procedure for calculating one-dimensional cylindrical and plane blast-wave flows in an ideally conducting perfect gas, including the effects of finite back pressure and an imposed magnetic field. The magnetohydrodynamic equations and shock conditions are transformed i…
V. È. Baskin
This paper develops an approximate formulation for the motion of spatial diffusing vortex tubes of small cross section in an unbounded incompressible viscous fluid, motivated by vortex flows behind wings and propeller blades. The approach assumes that the tube axis moves with the true induced veloci…
Yu. P. Gupalo
This paper develops a theory of diffusional aerosol deposition in fibrous filters for the case where neighboring fiber surfaces are separated by gaps small compared with the fiber diameter, a regime not covered by earlier dilute-cylinder models. Using lubrication hydrodynamics for flow through narro…
The paper considers spatial steady supersonic motions of a gas with a detached shock wave.
This paper develops a method of characteristics for calculating three-dimensional steady supersonic gas flows around blunt bodies with a detached shock wave, under the assumption of constant total enthalpy. It formulates an iterative construction for computing an individual point from an elementary …
S. K. ASLANOV
This paper develops an analytic stability criterion for plane Chapman Jouguet detonation in an ideal gas using Shchelkin’s model of a shock followed at finite distance by an instantaneous reaction front. Linearized jump conditions, a kinetic delay condition, and boundedness of perturbations are comb…
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This paper investigates the differing mechanical behavior of freshwater ice under uniaxial tension and compression, using specially prepared specimens and testing apparatus designed to record deformation diagrams. Experiments on columnar, acicular ice show that compressive strength is nearly nine ti…
S. M. BELONOSOV, M. A. ISMAILOV
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The paper solves an axisymmetric elasticity problem for an elastic half-space containing a point singularity of center type, representing compression or expansion, at a finite distance from a free boundary. Using an image construction to satisfy the shear boundary condition and a Hankel, Laplace tra…
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This paper studies an inverse boundary-value problem for pressure filtration: constructing the impervious underground contour of a hydraulic-engineering structure from a prescribed epure of exit velocities, with finite permeable-layer depth, given head, discharge, and filtration coefficient. Using t…
B. V. SHIROKORAD
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This paper reports an experimental study of turbulent flow of an electrically conducting liquid in a pipe subjected to a longitudinal magnetic field, a configuration in which the field primarily affects velocity fluctuations through Joule dissipation. Using a gallium loop with stainless steel pipes …
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This paper examines the proposed existence of a sharp secondary pressure maximum in a lubricating layer between deforming surfaces, a feature previously hypothesized to affect fatigue strength through stress concentration. Using a refined integral equation for the pressure function and associated hy…
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This note treats the elastic bending equilibrium of an isotropic plane plate resting on a doubly periodic system of point supports under an arbitrary doubly periodic transverse load. Using complex-variable formulations of plate theory, the authors construct a Green’s function in the fundamental peri…
I. S. Izrailevich, S. N. Novikov
This paper investigates gas flow through fine porous media in the transition pressure range, where the Knudsen number is near unity and the relation between permeability and mean pressure is theoretically uncertain. Using compacted highly dispersed powders with varied porosity, the authors measured …
I. Yu. Braidovskaya
The paper proposes an approximate method for calculating supersonic viscous gas flows in regimes where neither boundary-layer equations nor inviscid-flow equations alone are adequate. It formulates the problem as a singularly perturbed boundary-value problem and constructs a piecewise solution in wh…
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The paper studies basic three-dimensional boundary-value problems for composite isotropic elastic media with piecewise constant Lamé parameters and discontinuities across internal interfaces. It proposes a potential-theoretic reduction of these problems to systems of two-dimensional singular integra…
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This paper studies a linearized potential-flow problem for an incompressible fluid with jet separation past a permeable symmetric wedge, assuming that seepage velocity through the wedge is proportional to the pressure difference and that the permeability coefficient is small. Using a conformal mappi…
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This paper analyzes the reflection and refraction of plane one-dimensional plastic waves at the boundary between an elastic-plastic half-space and another medium. Using a uniaxial compression law in Lagrangian coordinates, the authors formulate governing equations for the incident, reflected, and re…
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This paper presents a finite difference method for two-dimensional unsteady flows of a viscous compressible heat-conducting gas with variable viscosity and thermal conductivity. The scheme is formulated for the Navier-Stokes equations in divergence form using a two-stage time update, with approximat…
A. V. IVANOV
This paper investigates the density field near the forward stagnation point of blunt bodies in a Mach 6 rarefied air flow, where thickening of the boundary layer and detached shock may create a continuous nonisentropic region. Using an electron-probe density measurement method in a low-density aerod…
E. M. KHAZEN
This paper develops a nonlinear analysis of the onset of turbulence in a viscous incompressible flow with a constant gradient of the mean velocity. Starting from the Navier Stokes equations in Fourier space, it studies finite-amplitude vortex disturbances by successive approximations, derives estima…
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This paper treats the determination of small free longitudinal vibration frequencies in finite rectilinear chains composed of diatomic and triatomic molecules under exact boundary conditions. Using previously introduced polynomial systems satisfying recurrence relations, the equations of motion are …
K. A. Kerimov
This paper reports experimental determination of the dynamic unloading behavior of Sh-65 rubber cord under transverse impact. Tests used a pneumatic impact apparatus with an added mass to reduce striker velocity during impact, while high-speed photography provided the established post-unloading velo…
V. M. Volosov, B. I. Morgunov
The paper studies stationary resonant rotational regimes in weakly perturbed nonlinear systems with one rotational coordinate and slowly varying parameters, without requiring the unperturbed system to be Hamiltonian. Assuming a periodic integral of the degenerate system is known, the authors transfo…
E. G. Albrecht
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The paper solves an axisymmetric consolidation problem for a fluid-saturated compressible porous half-space subjected to normal surface loading, using Biot’s equations with zero Poisson coefficient and boundary conditions corresponding to free drainage at the surface. By introducing potential functi…
Academician A. Yu. ISHLINSKY
This paper examines how elastic compliance in the rotor bearings, suspension, and mechanical transmission of a gyroscopic stabilizer affects its natural oscillation frequencies and stability, correcting the limitations of models that assume perfectly rigid elements. The author derives small-oscillat…
Corresponding Member of the Academy of Sciences of the USSR A. V. POGORELOV
This note addresses the stability of cylindrical reservoirs with flattened ellipsoidal bottoms under external pressure, a case relevant when internal vacuum can cause the bottom to bulge. Assuming axially symmetric postcritical deformation and approximating the bulge as a mirror-reflected segment, i…
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A method is proposed for determining the dynamic stress-strain relation of threadlike materials whose loading diagram contains an inflection point, using transverse impact theory and experimentally measured relations between impact velocity and kink angle. The procedure reduces the reconstruction be…
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This paper justifies the method of small oscillations for assessing stability and instability of stationary flows of a viscous incompressible fluid governed by the Navier-Stokes equations. The argument formulates the linearized problem as a spectral problem for an operator in solenoidal \(L_p\) spac…
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This note derives sufficient conditions for nonlinear Lyapunov stability of plane stationary curvilinear flows of an incompressible inviscid fluid under finite, circulation-preserving perturbations. Using variational arguments for dynamical systems with first integrals, the paper treats stationary E…
D. D. IVLEV, T. N. MARTYNOVA
The paper studies characteristic surfaces of weak discontinuity in the general equations for an ideal isotropic incompressible rigid-plastic body under smooth and piecewise-smooth yield conditions with an associated flow law. By analyzing jumps in derivatives of stresses, strain rates, and principal…
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This paper argues that the usual kinetic distribution function for a rarefied gas gives only the mathematical expectation of particle numbers in phase space and does not by itself provide a full probabilistic description of the gas motion. For a simple gas of structureless particles, it derives the …
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The paper examines how rapid rotation affects the instability and transition to turbulence of plane shear flows, using a tangential discontinuity in an incompressible rotating fluid as a model. Linearized equations in a rotating frame are used to compare two-dimensional disturbances, for which Corio…
A. M. Gokhman, E. V. N. Rao
This paper analyzes velocity fields generated by source and vortex singularities in a thin fluid layer whose thickness varies in one coordinate, motivated by flow past cascades in radial-axial hydraulic turbines. It formulates the governing potential equations, revises the boundary conditions at inf…
Corresponding Member of the USSR Academy of Sciences É. I. Grigolyuk, V. M. Tolkachev
The paper studies an infinitely long thin elastic circular cylindrical shell subjected to loads distributed along a finite segment of a generator, with load components directed longitudinally and circumferentially. Using Green’s functions for concentrated forces and asymptotic properties of Cauchy-t…
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This paper studies, in linear approximation, how an underwater ridge affects surface waves generated by an initial disturbance in an ideal incompressible fluid. The problem is formulated through a self-adjoint positive operator for the free-surface potential, then decomposed by Fourier transformatio…
L. M. Levin, Yu. S. Sedunov
This paper examines how particle inertia modifies diffusional deposition of aerosols from a flow when the Stokes number is below the critical value for direct inertial capture. Using coupled equations for particle motion and diffusion, the authors derive analytic results for a hyperbolic flow near a…
V. G. Levich, A. M. Brodskii
The paper develops a macrokinetic treatment of coupled homogeneous and surface reactions in moving media, motivated by cases where stationary-medium approximations are inadequate for liquids and gases. Using a tubular reactor as a representative geometry, it formulates convective diffusion with a bu…
G. M. KHATIASHVILI
The paper treats the bending of composite anisotropic cylindrical bodies with a slightly curved axis under a transverse force, extending earlier work for isotropic materials. By introducing a coordinate transformation that reduces the curved body to an associated straight composite cylinder to first…
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The paper examines the stability of equilibrium states in nonholonomic mechanical systems with linear velocity constraints. It argues that such equilibria are generally not isolated points but form a manifold whose dimension equals the number of nonholonomic constraint equations, explaining the occu…
V. A. Suchkov
The paper studies plane potential motions of a polytropic gas whose streamlines are stationary, treating the stationarity condition as an additional constraint on the unsteady gas-dynamic equations. By introducing velocity magnitude and direction and then using orthogonal curvilinear coordinates ada…
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This paper examines the group-theoretic meaning of the Riemann invariants for one-dimensional gas flow with plane waves. Using Cartan’s method of exterior forms, the governing gas-dynamic equations are rewritten as a Pfaffian system and transformed by canonization into basic invariant forms of a fin…
V. N. Monakhov
The paper studies the existence and uniqueness of plane subsonic potential gas flows with free boundaries, including Kirchhoff-type separated flows past obstacles or in channels and inverse or mixed problems for determining airfoil profiles from prescribed velocity data. The method transforms the ga…