Parameters of spatial flow past a hydrofoil near the free surface of a ponderable liquid

An approach is presented to the investigation of spatial flow past an submerged hydrofoil in the presence of a ponderable liquid. The approach uses the method of singularities, which represents the influence of the free surface of the water by the influence of an unbounded layer of sources. The linear solution is completely found for the problem of determining the wave production and downwash behind an submerged hydrofoil with given parameters of the eddy system. An estimate is made of the influence on the flow characteristics of nonlinear factors associated with the change produced by the wave production in the form of the free eddies leaving the hydrofoil. The distribution of the downwash in the flow behind the hydrofoil is found and recommendations given for the arrangement of a hydrofoil system with positive interaction of the elements. The results of the calculation are compared with experiment.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza., No. 2, pp. 54–62, March–April, 1979.     

Cambered wing of small aspect ratio near a boundary surface

Flow of an inviscid fluid past a thin longitudinally cambered wing of small aspect ratio near a solid or free (case of a hydrofoil) surface is investigated. The possibility of using a cylindrical twist (camber) of the wing to provide the necessary longitudinal trim and to reduce drag at a given lift is analyzed. The investigation is conducted by slender-body theory methods.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 49–55, November–December, 1971.     

Determination of the lift of a partially cavitated hydrofoil

New methods for the velocity circulation around partially cavitated hydrofoils are proposed for both short and long cavities. The calculated results are compared with available experimental data. The calculated lift and cavitation number dependences remain bounded as the cavity end approaches the trailing edge of the hydrofoil.St. Petersburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 71–74, November–December, 1994.     

Numerical solution of a nonlinear problem of the motion of a plane hydrofoil beneath the free surface of an ideal incompressible fluid

A nonlinear problem of the motion of a hydrofoil of infinite span beneath the free surface of an ideal incompressible fluid with gravity is studied. The stream function is used as the dependent variable. Iterative algorithms for small and large Froude numbers based upon solving a linear boundary value problem in each step with subsequent updating of the shape of the free boundary are proposed. Typical predictions are given for a symmetric profile at different values of the submersion depth, the Froude number and the angle of attack. The free surface and streamlines shapes are shown. The dependence of the lift on the submersion depth for motion through fluid layers of different thickness is presented.Dnepropetrovsk. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 100–107, July–August, 1995.     

Some nonlinear mathematical models of oscillation processes in a cross section of a vascular wall

We give some nonlinear mathematical models of oscillation processes in a cross section of a vascular wall.Translated from Neliniini Kolyvannya, Vol. 7, No. 3, pp. 356–364, July–September, 2004.     

Microcavitation in the slow motion of a solid spherical particle along a wall in a fluid

In the slow motion of a spherical particle along a wall, a cavity in the form of a non-spherical bubble is detected visually in the narrow particle-wall clearance. The nondimensional parameters associated with cavity formation are formulated and the effect of these parameters on the particle motion is investigated.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, 2004, pp. 110–118. Original Russian Text Copyright © 2004 by Prokunin.     

Asymptotic expansion of solutions of a singularly perturbed boundary-value problem

For linear singularly perturbed systems of ordinary differential equations, we construct an asymptotic expansion of a solution by using the method of boundary functions. Using pseudoinverse matrices and projections, we find all terms of the asymptotic expansion in the noncritical case.Translated from Neliniini Kolyvannya, Vol. 7, No. 2, pp. 155–168, April–June, 2004.     

Investigation of the structure of a strong electric discharge in a high-velocity air flow

Many studies devoted to both the theoretical and the experimental analysis of the problem of controlling the aerodynamic characteristics of vehicles using local heat-generating zones organized by means of external fuel combustion or directly as a result of the Joule dissipation of an electric current have recently been published. In this study attention is concentrated on the latter case.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, 2004, pp. 163–175. Original Russian Text Copyright © 2004 by Alfyorov.     

Structure of a gasdynamic disturbance in a thermodynamically nonequilibrium medium with a power-law relaxation model

The evolution and the steady-state structure of gasdynamic disturbances in a thermodynamically nonequilibrium gas are investigated both analytically and numerically. It is shown that in a medium with negative viscosity steady-state structures different from those in an equilibrium medium can exist. The conditions of existence of stationary shock waves with a discontinuous front and a smooth increase or decrease in the amplitude behind the front, waves with an oscillatory structure, and a stationary self-wave pulse with a power-law trailing front are determined.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, 2004, pp. 181–191. Original Russian Text Copyright © 2004 by Makaryan and Molevich.     

Macroscopic simulation of relaxation mass transport in a porous medium

The problem of the macroscopic simulation of the motion of a viscous fluid and mass transport in a porous medium is considered under the assumption that the mass transport can locally be described by the Fick relaxation law. Several cases determined by the local inertia number of the mass flow and the Péclet number are investigated. The macroscopic transport models are analyzed and compared with well-known phenomenological models.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, 2004, pp. 21–30.Original Russian Text Copyright © 2004 by Khuzhayorov.     

Nonlinear isochronous oscillations of a fluid in a paraboloid: theory and experiment

Within the framework of the shallow-water model, the nonlinear axisymmetric oscillations of a fluid in a paraboloid of revolution and in an unbounded parabolic channel are investigated. It is established that in the paraboloid of revolution the oscillation period does not depend on the amplitude, that is, the oscillations are isochronous. Experimental investigations of free fluid oscillations in a paraboloid confirm this theoretical result.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, 2004, pp. 131–142. Original Russian Text Copyright © 2004 by Kalashnik, Kakhiani, Lominadze, Patarashvili, Svirkunov, and Tsakadze.     

Long-wave convection in a two-layer system

Periodic regimes of large-scale convection in a two-layer system with a deformable interface are considered. In the limiting case of strong surface tension, an amplitude equation describing the interface deformation is derived. Two-dimensional periodic flow regimes are studied. It is shown that, depending on the governing parameters, both hard and soft excitation of convection is possible. In the presence of heating from above, the finite-amplitude excitation of convection was observed.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 5, 2004, pp. 7–20. Original Russian Text Copyright © 2004 by Lyubimov and Shklyaev.     

On the parametrization of three-point nonlinear boundary-value problems

A three-point boundary-value problem for a system of nonlinear differential equations is reduced to a family of two-point problems, whose solutions are investigated by using the numerical-analytic method.Translated from Neliniini Kolyvannya, Vol. 7, No. 3, pp. 395–413, July–September, 2004.     

Asymptotic Solutions of a First-Order Differential Equation with Deviating Argument and Slowly Varying Coefficients

The object of this paper is to study the problem of constructing an approximate solution of a first-order weakly nonlinear ordinary differential equation with deviating argument and slowly varying coefficients. On the basis of asymptotic techniques in nonlinear mechanics, we construct an algorithm for the asymptotic integration of the differential equation under consideration.__________Published in Neliniini Kolyvannya, Vol. 7, No. 4, pp. 475–486, October–December, 2004.     

Dynamic loading of cylindrical and spherical bodies interacting with a shock wave

Empirical formulas for diffraction pressure on the surface of a ball and a cylinder interacting with a weak shock wave are derived based on experimental data.__________Translated from Prikladnaya Mekhanika, Vol. 40, No. 12, pp. 117–123, December 2004.     

Non-axisymmetric oscillations of a hemispherical drop

Natural oscillations of a hemispherical drop on a solid substrate are considered. The Hocking condition is used to take into account the contact angle dynamics. The natural oscillations attenuate due to dissipation on the contact line and the degeneracy in the azimuthal number is eliminated. Forced oscillations of the drop are studied for tangential vibrations of the substrate. For the case of a fixed contact line, the amplitude of the forced oscillations grows without bound near the fundamental requency. In other cases, the amplitude is finite.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, 2004, pp. 8–20. Original Russian Text Copyright © 2004 by Lyubimov, Lyubimova, Shklyaev.     

Existence of Green-Samoilenko Functions of Some Linear Extensions of Dynamical Systems

We study the problem of the existence of a Green-Samoilenko function for some linear extensions of dynamical systems.__________Translated from Neliniini Kolyvannya, Vol. 7, No. 4, pp. 468–474, October–December, 2004.     

Assessment of two‐equation turbulence modelling for high Reynolds number hydrofoil flows

This paper presents an evaluation of the capability of turbulence models available in the commercial CFD code FLUENT 6.0 for their application to hydrofoil turbulent boundary layer separation flow at high Reynolds numbers. Four widely applied two‐equation RANS turbulence models were assessed through comparison with experimental data at Reynolds numbers of 8.284×106 and 1.657×107. They were the standard k–εmodel, the realizable k–εmodel, the standard k–ωmodel and the shear‐stress‐transport (SST) k–ωmodel. It has found that the realizable k–εturbulence model used with enhanced wall functions and near‐wall modelling techniques, consistently provides superior performance in predicting the flow characteristics around the hydrofoil. Copyright © 2004 John Wiley & Sons, Ltd.     

Influence of acoustic radiation on the sensors of a gyrostabilized platform

The paper analyzes the joint effect of acoustic radiation and angular motion of a launch vehicle on the gyroscopic sensors of a three-axis gyroplatform and the operation of the stabilizer under synchronous and asynchronous swinging.Translated from Prikladnaya Mekhanika, Vol. 40, No. 10, pp. 122–130, October 2004.     

Simulation of micellar-polymericwater-flooding in a system of wells

A mathematical model of the time-dependent two-dimensional flow of a two-phase multicomponent incompressible fluid through a porous medium is proposed for the micellar-polymeric flooding of oil reservoirs. The oil displacement process is investigated numerically using an implicit first-order-accurate upwind scheme with integration over the nonlinearity on a uniform grid under the assumption of plane-radial motion in the neighborhood of the wells. The influence of the nonuniform permeability of the porous medium on the efficiency of the proposed method of improving oil recovery is analyzed using a five-point slug injection scheme.Translated from Izvestiya Rossiiskoi Academii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, 2004, pp. 124–132. Original Russian Text Copyright © 2004 by Inogamov and Khabeev.