Plane problem of wave motions occurring in a continuously stratified fluid during the flow around a submerged body

The plane stationary problem of wave motions occuring in the flow of a uniform inviscid incompressible gravity fluid with an arbitrary continuous (stable) change in density with depth around submerged sources and sinks of equal intensity is investigated in a linear formulation. An analysis of the structure of the wave motion in a flow with an arbitrary density change is performed in [1].Paper presented at the First Soviet-American Symposium on Internal Waves in the Ocean, Novosibirsk, December 3–8, 1976.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 148–152, July–August, 1978.     

Cavitation flow around a plate in a channel by a stream of heavy liquid

The nonlinear problem of cavitation flow around a plate by a stream of heavy liquid is investigated in precise formulation; the plate is located on the horizontal floor of a channel when the gravity vector is directed perpendicular to the wall of the channel. Two flow systems are considered-Ryabushinskii's and Kuznetsov's system [1]. This problem was investigated in linear formulation in [2], Similar problems were considered earlier in [3–7] for unrestricted flow. Below, on the basis of a method proposed by Birkhoff [8, 9], all the principal hydrodynamic and geometric characteristics are calculated for the problem being considered.Translated from Ivestiya Akademii Nauk SSSR. Mekhanika Zhidkosti i Gaza, No. 3, pp. 3–9, May–June, 1973.     

Three-dimensional problem for entry of a disk into a compressible liquid

The unsteady problem for the oblique entry of a disk into water is solved. The water is assumed a perfect compressible liquid and the flow is assumed adiabatic. The flow and state parameters are determined during the numerical integration of the system of nonlinear equations which describe the given flow by means of a three-dimensional finite-difference scheme [1]. The variation in time of the drag coefficient as a function of the Mach number and the angles of entry and attack, the pressure distribution and the shape of the free surface formed behind the disk are investigated. The oblique entry of a disk into water and its subsequent motion have mainly been studied for velocities at which the compressibility of the water is negligible [2–4]. The influence of compressibility on the duration of the rise time and the impact load was investigated experimentally in the range of Mach numbers 0 < M0 <–0.3 [5]. Semiempirical dependences are obtained for the maximum of the drag coefficient and its rise time.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 17–20, January–February, 1988.     

Formation of discontinuities in the wake of a cylinder in a stratified flow

The results of an experimental investigation of continuously stratified flow past a cylinder are presented. It is shown that interfaces with an elevated value of the density gradient (discontinuities) are formed in the wake.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 20–26, January–February, 1993.     

Motion of a suspension in the laminar boundary layer on a flat plate

The boundary layer motion of a weak suspension is investigated with allowance for the effect on the particles not only of the Stokes force but also of the additional transverse force resulting from the transverse nonuniformity of the flow over the individual particle. As distinct from studies [1–3], in which the limiting values of the transverse force (Saffman force) were used [4], the velocity and density of the dispersed phase have been determined with allowance for the dependence of the Saffman force on the ratio of the Reynolds numbers calculated from the velocity of the flow over the individual particle and the transverse velocity gradient of the undisturbed flow, respectively [5, 6].Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 66–73, January–February, 1992.In conclusion the authors wishes to thank M. N. Kogan, N. K. Makashev, and A. Yu. Boris for useful discussions of the results.     

Effect of finite depth of stratified flow on turbulence formation in the wake of a cylinder

The experimental results of investigating the effect of the finite depth of a linearly stratified flow channel on turbulence formation associated with the horizontal motion of a cylinder are presented. The limits of the interval of internal Froude numbers and dimensionless channel depths (with respect to the cylinder diameter) corresponding to local instabilites in the disturbed flow density distribution, leading to the formation of turbulence, are found. The dynamics of formation of the turbulent zones and their evolution are investigated. Unsteady periodic regimes are found.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 160–163, September–October, 1990.The authors are grateful to A. T. Onufriev for his interest in their work.     

Influence of magnetic reynolds number on the current distribution in a magnetohydrodynamic channel with allowance for the Hall effect

Stationary plane flow of a conducting gas across a magnetic field in a magnetohydrodynamic channel of constant cross section made up of electrodes of finite length and insulators is considered in the linear approximation. It is assumed that the electromagnetic forces are small. It is shown that the current density increases near the exit from the interelectrode gap with increasing magnetic Reynolds number. The mutual influence of the Hall parameter and of the magnetic Reynolds number on the distribution of the currents in the channel is investigated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 148–152, May–June, 1971.     

Density distribution in rarefied gas flow behind a perforated plate

The relative density distribution in the rarefied CO₂ flow field behind a perforated plate has been experimentally investigated on the range of Knudsen numbers 10^–3 Kn 10^–1. The results of these experiments serve to demonstrate the validity of using the molecular velocity distribution function for determining the relative density on the Knudsen number interval in question. This distribution function was previously employed for calculating the parameters in molecular beams formed by capillary sieves in the free-molecular flow regime [1].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 3, pp. 183–184, May–June, 1989.     

Law of transverse sections for the three-dimensional boundary layer on a thin wing in a hypersonic stream

The investigation of three-dimensional flows in boundary layers is important to determine the aerodynamic characteristics of wings such as the heat fluxes and friction drag. However, the circumstance that interaction of the boundary layer and the wake with an inviscid stream can play a governing role for the formation of the flow diagram as a whole is more important. The three-dimensional flow on a thin delta wing in a hypersonic stream is investigated in this paper. An important singularity of hypersonic flow is the low value of the gas density in the boundary layer as compared with the density on its outer boundary. It is shown that in the general case when the pressure in the wing span direction varies mainly by an order, high transverse velocities originate because of the smallness of the density within the boundary layer. This circumstance permits expansion of the solution for smallspan wings in a series in an appropriate small parameter. The equations in each approximation depend on two variables, while the third—longitudinal—variable enters as a parameter. The zero approximation can be considered as the formulation of the law of transverse plane sections for a three-dimensional boundary layer. As a comparison with the exact solutions calculated for delta wings with power-law distributions of the wing thickness has shown, the first approximation yields a very good approximation. Furthermore, flow modes with a different direction of parabolicity on the whole wing, as well as zones in which interaction with the external stream should absolutely be taken into account, are found.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 75–84, March–April, 1976.     

Primary pressure wave in a fluid after actuation of a pipeline valve

This paper considers the variation in the velocity, density, and pressure of an inviscid compressible fluid due to flow acceleration or deceleration after a change in the flow area of a valve installed on the pipeline with rigid walls. Expressions are given for the amplitude of the primary compression or rarefaction wave resulting form the change in flow area of the valve.Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 1, pp. 78–84, January–February, 2005     

Interaction of light with a turbulent liquid flow

The relation between the rms fluctuation of a light current and the density fluctuation in a turbulent liquid flow is considered. Criteria are established for the effect of medium turbulence on the refractive index and on light attenuation. Experimental apparatus and new experimental data are described.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 115–123, July–August, 1973.     

Flow past a three-dimensional hump in the hypersonic boundary layer on a cooled body

Hypersonic gas flow past a small hump on the surface of a cold body has been investigated. The main parameters controlling the physical features of the flow in the near-wall viscous layer are determined. The solution of the boundary-value problem on a viscous sublayer along the symmetry line of flow past a wedge of finite span has been investigated numerically and the influence of the similarity parameters demonstrated.Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.1, pp. 157–165, January–February, 1993.     

Velocity field in a cylindrical hydrocyclone

The flow in a cylindrical hydrocyclone is investigated at moderate Reynolds numbers. Such a flow regime is realized in a hydrocyclone when, for example, certain solid particles are separated. The flow is calculated in the frame-work of the theory of an inviscid incompressible fluid, since the influence of turbulent pulsations on the flow structure in the investigated flow regime (Reynolds numbers of the order of a few thousand) is slight. Comparison of the results with experimental data indicates good qualitative agreement.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 12–20, November–December, 1980.I thank Yu. P. Gupalo and Yu. S. Ryazantsev for discussing the work and for valuable comments.     

Steady-state wave flows of a weakly conducting gas in transverse electromagnetic fields

Gas flow in a MHD channel in transverse magnetic and electric fields is considered. The steady-state flows associated with the establishment of equilibrium between the hydraulic resistence and ponderomotive forces are investigated. The conditions of existence and the properties of such a steady-state flow regime are analyzed.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 123–129, July–August, 1990.     

Calculation of the characteristics of a gas-dynamic laser

The dependence of the radiated power on the characteristics of optical cavities in the case of flow systems has been investigated in a number of papers [1–3], in which it is assumed that population inversion of the laser levels is obtained until entry into the cavity. The operation of a cavity is analyzed in [1] in the geometric-optical approximation with allowance for vibrational relaxation in the gas flow. A simplified system of relaxation equations is solved under steady-state lasing conditions and an expression derived for the laser output power on the assumption of constant temperature, density, and flow speed. The vibrational relaxation processes in the cavity itself are ignored in [2, 3]. It is shown in those studies that the solution has a singularity at the cavity input within the context of the model used. In the present article the performance characteristics of a CO₂-N₂-He gas-dynamic laser with a plane cavity are calculated. A set of equations describing the processes in the cavity is analyzed and solved numerically. Population inversion of the CO₂ laser levels is created by pre-expansion of the given mixture through a flat hyperbolic nozzle. The dependence of the output power on the reflectivities of the mirrors, the cavity length, the pressure, and the composition of the active gas medium is determined.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi FiziM, No. 5, pp. 33–40, September–October, 1972.     

Nonstationary waves in the continuously stratified flow of a fluid of finite depth

A theoretical investigation is made of the development of linear two-dimensional waves in a continuously stratified flow of an ideal incompressible fluid. The waves are generated by pressures that are independent of time and that are applied at time t=0 to a bounded region on the free surface of an initially undisturbed flow. The stationary internal waves generated by such a disturbance have been investigated in [1–3]. The nonstationary waves in a continuously stratified fluid that are generated by initial disturbances or periodic surface pressures applied to the entire free surface have been studied in [4–7] in the absence of a slow.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 87–93, November–December, 1976.     

On the development of plane waves generated by a periodic pressure applied to the flow of a continuously stratified fluid

In the linear formulation, an investigation is made into the development of undamped (in time) plane waves generated by a. harmonically varying pressure applied to the free surface of an initially undisturbed flow of a continuously stratified fluid of finite depth. The cases of a homogeneous fluid and two-layer fluid are considered in [1–3]. Nonstationary waves in a continuously stratified flow generated by a time-independent pressure were investigated in [4].Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 99–104, July–August, 1980.     

Asymptotic theory of laminar flow separation at a corner

The development of the reverse flow structure in the neighborhood of a corner in a viscous incompressible laminar flow at high Reynolds numbers is investigated numerically. It is found that as the angle of inclination increases the internal structure of the reverse flow zone becomes more complex as a result of secondary separation. The effect of the curvature of the surface is investigated.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 1, pp. 180–182, January–February, 1991.     

Numerical study of the behavior of a uniform “spot” in an ideal density-stratified liquid

A numerical analysis of the flow arising as a result of the collapse of a uniform spot in a heavy ideal liquid linearly stratified with respect to density is presented. The nonlinear model of the phenomenon is employed. The numerical results are compared with experiment.Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 3, pp. 120–126, May–June, 1973.     

Experimental investigation of the flow in the separation zones of a turbulent boundary layer upstream from a two-dimensional step

The flow in the separation zones of a turbulent boundary layer upstream from a two-dimensional rectangular step has been experimentally investigated at subsonic flow velocities. The flow pattern and the static pressure distributions on the surface of the plate and the step are analyzed and the characteristic dimensions of the separation zones and the boundary-layer parameters in the separation section are determined.Moscow. Translated from Izvestiya Akademii Nauk SSSR. Mekhanika Zhidkosti i Gaza, No. 2, pp. 145–149, March–April, 1972.