Initiation of intense pressure fluctuations when a flow is turned in a duct with a blind-ended cavity

The initiation of narrow-band pressure fluctuations in the duct of a pipeline gas-compression station when the flow is turned near a blind-ended cavity was studied in a wind tunnel. The flow pattern under consideration was estimated from visualization of the flow in a water channel using the hydraulic analogy technique. It is believed that the high-intensity narrow-band pressure fluctuations observed in the flow result from the instability and regular rearrangement of large-scale vortex structures in the blind-ended cavity. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 104–111, March–April, 1998.     

Some primal problems of the axisymmetric theory of elasticity for space with a flat slit bounded by a circle

We consider the first and second primal problems of the axisymmetric theory of elasticity for space with a round slit and a mixed problem in which forces are specified on one side of the slit and displacements are specified on the other side. The problems reduce to conjugation problems for generalized analytic functions on rectilinear segments, whose solution is obtained in closed form. Institute of Applied Mechanics, Russian Academy of Sciences, Moscow 117334. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 1 pp. 144–151, January–February, 2000.     

Exact solutions of problems of steady fluid flow in reservoirs with hydrofractures

The plane steady flow of a homogeneous fluid between several wells in a reservoir zone containing hydrofractures is considered. Under the assumption of infinite fracture conductivity, analytic solutions of the Laplace equation for the pressure distribution in the elements of several typical symmetrical well arrangements are obtained, thus enabling them to be compared. Since the conductivity of the fracture may have a significant effect on the flow, the influence of its hydraulic properties on the productivity of a producing well is numerically investigated. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 74–82, March–April, 1994.     

Charged jet of an incompressible liquid in an electric field

The problem of the jet flow of an incompressible liquid with free boundaries in an electric field is solved in the approximation of a laminar boundary layer. An exact solution for a round jet is found in the class of self-similar solutions. In the case of a flat slit jet, a solution is constructed in the form of a series in powers of the coordinate transverse to the plane of symmetry. The dependence of the radius (half-width) on the longitudinal coordinate is given. Branch of the Karpov Physicochemistry Institute, State Science Center, Obninsk 249020. Karpov Physicochemistry Institute, State Science Center, Moscow 115523. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 4, pp. 12–16, July–August, 1998.     

Self-sustaining thermoconvective flows in the absence of external force fields

It is shown, analytically and numerically, that if there are no external force fields and the hydraulic resistance is low, sustained thermoconvective subsonic flows may exist in a closed channel of variable cross section, in the wider part of which the medium is heated while in the narrower part it is cooled. The flow parameters depend on the equation of state of the medium, the channel geometry and the amount of heat transferred by the flow from the heated to the cooled part. Steady thermoconvective flows exist up to a certain critical value of the thermal power transported by the flow. The relation between the results obtained and the mechanism by which the motion of the medium is sustained in natural convection is discussed. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 11–17, March–April, 1994.     

Calculation of a transport current from a nozzle with two-phase flow in the presence of a corona discharge

The operation of a source of charged aerosol particles which consists of a supersonic nozzle, a corona-forming needle-shaped electrode, and a device for injecting liquid droplets into a gas flow is considered. A theoretical model for two-dimensional, two-phase flow in the nozzle is considered. An algorithm of numerical calculation of such a flow is developed, and results of calculations of the electric transport current from the nozzle are given. Institute of Mechanics, Moscow State University, Moscow 117192. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 39, No. 6, pp. 102–109, November–December, 1998.     

Exact solution of the problem of convective heat exchange for a circular cylinder at small Prandtl numbers

The problem of the heat exchange of a circular cylinder in an incompressible flow at small Prandtl numbers Pr ≪ 1 is solved. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 43–48, January–February, 1994.     

Pressure oscillation on a plane upstream of an obstacle in a supersonic flow

The levels and spectra of pressure oscillation on a plane upstream of a vertical cylinder and a step in an M=3 supersonic flow are measured in the presence of a turbulent boundary layer. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 69–74, January–February, 1998.     

Flow pattern in the vicinity of an annular system of transverse jets in a supersonic stream

The pattern of the flow in the vicinity of an annular system of jets exiting into a supersonic stream from orifices on a cylindrical surface with a turbulent boundary layer is experimentally investigated Four typical flow regimes are recorded The effect of the jet number and the nozzle-to-outer pressure ratio on the extent of the separation zone and its structure ahead of and behind the jet system is determined Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 21–27, January–February, 1999.     

Convergent laminar fluid flow between two rotating disks

A stationary flow from the periphery to the center in a hollow between two coaxial, closely located rotating disks is studied by the iterative method of solving a system of equations of the dynamics of a viscous incompressible fluid. The existence and uniqueness of the approximate solution are shown. Moscow State University of the Food Industry, Moscow 125080. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 41, No. 2, pp. 77–83, March–April, 2000.     

Properties of pulsating blood flow through resistive blood vessels

The results of measuring the resistance when the flow changes from steady to pulsating are discussed on the basis of simple mathematical models of the individual vessel and the microvascular module. Moscow, St Petersburg. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 83–89, March–April, 1994.     

A sharp slender cone in an incompressible flow

The range of applicability of the asymptotic solution of the problem of incompressible flow past a slender cone is studied. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 197–200, July–August, 1998.     

Calculation of two-phase swirling flows

The results of calculating the diffusion of a dispersed admixture in turbulent swirling jet flows using the model of momentum transfer in a turbulent gas—dispersion flow proposed by the authors are presented. These results are compared with experimental data and with calculations based on various mathematical models. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 71–78, January–February, 1994.     

On the applicability of some approximate similitude laws in hypersonic aerodynamics

The range of applicability of some similitude laws for heat transfer, friction and drag coefficients is discussed on the basis of numerical solutions of the complete viscous shock layer equations describing hypersonic flow past blunt bodies. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 121–130, March–April, 1994.     

Regimes of laminar lateral flow separation due to jet exhaust

Numerical simulation of the separation flow on the lateral surface of an aircraft due to interaction between the engine exhaust plume and the external air-stream is carried out on the basis of the full Navier-Stokes equations. Three separated flow regimes are revealed, namely, closed, open and periodic. The conditions under which each of these three regimes may exist are determined. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 132–138, January–February, 1994.     

Analytical study of supersonic isentropic flow in a channel of constant cross section and an adjacent laval nozzle. Comparison with numerical and experimental results

An analytic study of plane supersonic flow based on the use of Prandtl-Meyer invariants is presented. Flow in both a channel of constant cross section and an adjacent Laval nozzle with a corner point is considered. The analytical results are compared with numerical and experimental data. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 158–169, July–August, 1994.     

Law of flow of a viscoplastic fluid through a porous medium with allowance for inertial losses

A macroscopic law of flow of a viscoplastic Schwedoff-Bingham fluid through a porous medium is obtained on the basis of percolation theory with allowance for viscous and inertial losses. The asymptotics of the flow law are estimated and expressions for determining the limiting pressure gradient as a function of the microinhomogeneity parameters are given. Satisfactory qualitative agreement between the theoretical and known experimental data is observed. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 68–73, January–February, 1999.     

Three-dimensional flows of thin layers of viscoplastic media in deformable channels and cavities

The problem of the three-dimensional flow of a viscoplastic medium in a thin layer bounded by two deformable material surfaces whose points are displaced transversely across the layer is formulated and solved. Expressions for the velocity components and the flow-rate and equations for calculating the pressure and the boundary of the shear flow region are obtained. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 4, pp. 201–205, July–August, 1998.     

The pattern and restructuring of supersonic flow past a pair of bodies

The pattern of symmetric and asymmetric supersonic flow past a pair of isolated/connected bodies is analyzed. Semiempirical dependences of the critical parameterl ^*, determining direct and reverse flow restructuring, on the geometry and permeability of the bodies and the Mach and Reynolds numbers are derived using experimental data. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 158–165, January–February, 1994.