Effect of external flow on the flow rate of a gas discharged through an orifice

The dependence of the flow coefficient of a gas jet ejected from an orifice/nozzle into a subsonic/transonic cross-flow on the flow and the jet Mach numbers, the off-design ratio, the nozzle inclination angle, β, and other determining parameters is considered. The physical nozzle flow pattern is constructed on the basis of experimental data obtained for 0.3< M_∞<1.75 and β=60°, 90°, and 120°. The results of measuring the pressure upstream and downstream of the orifice and on the windward and leeward orifice generators are presented. It is shown that the flow rate coefficient of a jet ejected into a cross-flow may exceed that of a similar jet outflowing into a flooded space. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 65–70, May–June, 1998.     

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.     

Comparative analysis of turbulence models for calculating a near-wall boundary layer

The integral relations, the algebraic model, and the family of differential turbulence models widely used in theoretical and practical boundary layers studies are considered. The differential turbulence models are analyzed for fully developed incompressible-fluid flow in three regions: the viscous sublayer, the logarithmic layer, and the flow core. Numerical results are compared with analytical and experimental dependences. The numerical results for the boundary layer in a liquid rocket engine (LRE) nozzle, where compressibility, the temperature factor, and flow acceleration are significant, are presented. Recommendations on the applicability of the turbulence models considered are given. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 44–58, January–February, 1998. The work received financial support from the Russian Foundation for Fundamental Research (project No.96-01-00260).     

Calculation of the effect of a constant electric field on the gas dynamics and nitrogen oxide emission in a laminar diffusion flame

A laminar methane diffusion flame in a constant electric field whose direction is opposite to that of the velocity of the gas flow from the burner nozzle is considered. The mathematical model used includes the complete system of Navier-Stokes equations for the velocity and passive admixture concentration fields, the charge transport equation, together with the Poisson equation for the self-consistent electric field, and the chemical kinetic equations for a thin combustion zone. The calculations show that the flame shortens and its thickness increases in the root zone when an electric field is imposed. This effect is accompanied by a reduction in the nitrogen oxide emission, while is consistent with the experimental data. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 48–53, January–February, 2000. The work was supported by the Russian Foundation for Basic Research (project No. 96-01-014-50).     

Solution of some problems of particle motion in a gas stream

The problem of designing the contour of an optimum nozzle for particle acceleration is considered in the one-dimensional formulation. In [1] a similar problem was solved in the general formulation using a numerical method. Here, in contrast to [1], the solution is obtained in analytic form for the particular case of low particle concentration. The problem of the motion of a particle in a uniform stream is solved in the same form. Moscow. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 86–90, September–October, 1988.     

Determination of the optimal contour of a supersonic jet engine outlet by the direct method

The variational problem of determining the optimal contour of an outlet system consisting of the supersonic jet-engine nozzle and the tail of the flight vehicle is solved by the direct method. Some optimal contours of two-dimensional outlet systems are calculated taking the effects of the external flow, the base, the angle of attack, and certain other factors into account. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 169–178, January–February, 1998.     

Investigation of a Gas Flow with Solid Particles in a Supersonic Nozzle

A two-phase flow with high Reynolds numbers in the subsonic, transonic, and supersonic parts of the nozzle is considered within the framework of the Prandtl model, i.e., the flow is divided into an inviscid core and a thin boundary layer. Mutual influence of the gas and solid particles is taken into account. The Euler equations are solved for the gas in the flow core, and the boundary-layer equations are used in the near-wall region. The particle motion in the inviscid region is described by the Lagrangian approach, and trajectories and temperatures of particle packets are tracked. The behavior of particles in the boundary layer is described by the Euler equations for volume-averaged parameters of particles. The computed particle-velocity distributions are compared with experiments in a plane nozzle. It is noted that particles inserted in the subsonic part of the nozzle are focused at the nozzle centerline, which leads to substantial flow deceleration in the supersonic part of the nozzle. The effect of various boundary conditions for the flow of particles in the inviscid region is considered. For an axisymmetric nozzle, the influence of the contour of the subsonic part of the nozzle, the loading ratio, and the particle diameter on the particle-flow parameters in the inviscid region and in the boundary layer is studied. __________ Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 46, No. 6, pp. 65–77, November–December, 2005.     

Supersonic flow past a sharp cone oscillating about a zero angle of attack

Supersonic perfect gas or equilibrium dissociated air flow past a sharp circular cone oscillating about a zero angle of attack is considered at small Strouhal numbers. The distribution of the gasdynamic parameters in the flow is found within the framework of the linear theory of finite-thickness bodies. The domain of the determining parameters for which the effect of equilibrium dissociation is substantial is found. The pitch moment coefficient related to the angular velocity of vibration is determined. Analytic expressions are derived for the gasdynamic characteristics at hypersonic flow velocities. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 124–136, November–December, 1998.     

Supersonic ideal-gas flow of in the throat region of a nozzle

The problem of profiling a supersonic nozzle with uniform outlet flow is considered when the contour is constructed from a point on a given convergent section of the nozzle. It is shown that there are contours such that the flow in the throat is supersonic in choked regimes (as distinct from common notions of mixed or uniform sonic flow). The influence of flow nonuniformity in the throat region on the thrust of a supersonic nozzle is analyzed.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 132–139, May–June, 1996.     

Calculation of spatial flow past an inclined flat plate with a detached shock wave

The results of a numerical analysis of a supersonic underexpanded jet impinging on an inclined flat plate are presented. The effects of the angle between the plate and the jet symmetry axis, the distance from the nozzle exit section, the exit Mach number, and the off-design conditions on the distribution of the gasdynamic parameters in the jet flowfield and on the plate surface are demonstrated. Specific features of the compressed layer and obstacle surface flows are revealed. The three-dimensional flow is simulated using the large particle method on the basis of the nonstationary Euler equations written in the cylindrical coordinate system. The calculated results are compared with experimental data. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 31–35, January–February, 1997.     

Flow and stability of a free axisymmetric film

Axisymmetric free film flows are encountered in many technological processes [1] associated with the atomization of liquids. The transversely symmetric flow produced by an atomizer consisting of two coaxial disks rotating at the same speed and arranged to form an annular gap is considered. Moscow. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 23–29, September–October, 1988     

Forces and torques exerted on bodies sliding in a fluid

The motion of a system of bodies along a plane in a viscous fluid in the presence of flow shear is considered. It is demonstrated that a main torque, linearly proportional to the velocities of the bodies, is exerted by the fluid on the system of the bodies and the plane. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 89–96, January–February, 1997.     

Delta wing in a subsonic flow

On the basis of experimental wind tunnel research, a topological classification of possible delta wing flow regimes is given and a diagram in angle of attack-sweep angle coordinates is constructed. A regime with two pairs of symmetrically disposed whirlwind like vortices formed on the surface of the wing is detected. The effect of the V-shape of the wing is considered. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No.2, pp. 161–164, March–April, 1994.     

Design of the optimal nozzle of a hypersonic flight vehicle for given overall dimensions and moment

The problem of designing the optimal nozzle of a hypersonic ramjet engine for a given isoperimetric condition imposed on the moment and restricted overall dimensions is solved by the method of an indefinite control contour. The lift of the flight vehicle is treated as the optimized functional. It is shown that an increase in the moment due to the replacement of thrust optimization by lift optimization is efficiently compensated by taking the moment constraint into account. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 118–124, January–February, 1999.     

Motion of a hot wedge in a melting medium

In [1–3] a series of problems of the motion of heat sources at a temperature higher than the melting point of the surrounding medium was considered. The heat source could be a laser beam or a hot body. Here, the case of a thin wedge heated to a temperature higher than the melting point of the surrounding medium and moving at a constant velocity is investigated. The velocity is high enough for the molten layer formed to be thin. The problem is solved by the method of integral relations. The shape of the molten zone, the drag on the wedge and other flow characteristics of the melt are determined. Moscow. Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 52–57, September–October, 1988.     

Stability of a compressible swirling flow in a circular pipe

The stability of an axisymmetric flow of viscous gas in a circular pipe, which models the Burgers vortex in the pipe axis neighborhood, is studied within the linear theory framework. Neutral curves for the most unstable disturbances are calculated. The influence of the characteristic Mach number on the flow stability is investigated. It is shown that for a given model velocity distribution the Mach number affects only the temperature and pressure profiles of the main undisturbed flow. In this case, for the disturbance types considered, as the Mach number increases, the critical Reynolds number corresponding to loss of stability decreases. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 1, pp. 35–41, January–February, 1999. The work received financial support from the Russian Foundation for Basic Research (project No. 96-01-00586).     

Effect of fluid compressibility on the linear stability of Poiseuille flow in a circular tube

The linear stability of a barotropic fluid flow in a circular absolutely rigid tube is considered. The behavior of perturbations in the form of monoharmonic waves resulting from the viscosity as well as the compressibility of the fluid is investigated. It is shown that the compressibility of the fluid affects the first type of perturbations only slightly and the second significantly and that the latter can be more dangerous from the standpoint of initiating instability, even for weakly compressible flows. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 2, pp. 5–10, March–April, 1994.     

Stability of a spanwise nonuniform boundary layer flow

The linear stability of a boundary layer flow with a spanwise-periodic nonuniformity in the velocity profile is investigated. This flow can be considered as a model of a streaky structure occurring in the boundary layer at a high freestream turbulence level. It is shown that for a small nonuniformity amplitude symmetric modes similar to Tollmien-Schlichting waves are the most unstable. At higher nonuniformity amplitudes, antisymmetric modes, qualitatively different from Tollmien-Schlichting waves and having a larger phase velocity, are the most amplified. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 54–63, November–December, 1998. The study was carried out with the support of the International Scientific and Technical Center (project No. 199-95) and the Russian Foundation for Basic Research (project No. 95-01-01201a).     

Thermo-gravitational and vibrational convection in a near-critical gas in microgravity

The flow and heat transfer in a medium near the critical point (second-kind liquid-gas phase transition) in a stationary and oscillating mass force field is considered in relation to the experiments conducted in microgravity. The conditions of onset of a mean convective flow and the characteristic nondimensional parameters describing the vibrational and thermo-gravitational convection in the medium are analyzed. It is shown that even low-frequency and small-amplitude vibrations or steady microaccelerations can induce appreciable convective flows. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 70–80, May–June, 2000. This study received financial support from the Russian Foundation for Basic Research (project 97-01-00124).     

Stability of a viscous subsonic swirl flow

The results of calculating the stability of a three-dimensional swirl flow of a viscous heat-conducting gas are presented. The stability characteristics are determined using the linear time-dependent theory of plane-parallel flow stability. The main undisturbed axisymmetric vortex flow was determined numerically using a quasi-cylindrical approximation for the complete set of Navier-Stokes equations. The circulation of the peripheral velocity in the cocurrent flow surrounding the viscous vortex core was assumed to be constant. In analyzing the stability, nonaxisymmetric perturbations in the shape of waves traveling along the vortex axis with both positive and negative wavenumbers were considered; in these two cases the perturbation rotation is either the same or opposite in sense to the rotation in the vortex core. Neutral stability curves are determined for various values of the swirling parameter and the cocurrent flow Mach number. Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 3, pp. 50–59, May–June, 1998.