Penetration depth of a jet injected into an oncoming supersonic flow

The geometrical characteristics of jets injected through an opening in a flat plate into an oncoming supersonic flow have been studied on a number of occasions [1, 3]. However, the results were analyzed under different suppositions about the important dimensionless parameters. In [1], the degree of underexpansion of the jet, characterized by n = p _a /p, was regarded as decisive; in [3], the experimental points were plotted against the relative dynamic head _a u² _a /(u² ) of the jet. In the present paper, dimensional considerations are used to determine the dimensionless parameters which influence the flow field when an injected jet interacts with an oncoming supersonic gas flow. The influence of these determining dimensionless parameters on the depth of penetration of injected jets into a flow was investigated experimentally. It is shown that the relative depth of penetration is determined basically by the relative specific impulse of the jet, the injection angle, and the shape of the blowing nozzle section.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 151–154, July–August, 1980.     

Flowfield characteristics of a transverse jet into supersonic flow with pseudo-shock wave

We performed an experimental investigation of the flowfield of a transverse jet into supersonic flow with a pseudo-shock wave (PSW). In this study, we injected compressed air as the injectant, simulating hydrocarbon fuel. A back pressure control valve generated PSW into Mach 2.5 supersonic flow and controlled its position. The positions of PSW were set at nondimensional distance from the injector by the duct height (x/H) of ?1.0, ?2.5, and ?4.0. Particle image velocimetry (PIV) gave us the velocity of the flowfield. Mie scattering of oil mist only with the jet was used to measure the spread of the injectant. Furthermore, gas sampling measurements at the exit of the test section were carried out to determine the injectant mole fraction distributions. Gas sampling data qualitatively matched the intensity of Mie scattering. PIV measurements indicated that far-upstream PSW decelerated the flow speed of the main stream and developed the boundary layer on the wall of the test section. The flow speed deceleration at the corner of the test section was remarkable. The PSW produced nonuniformity in the main stream and reduced the momentum flux of the main stream in front of the injector. The blowing ratio, defined as the square root of the momentum flux ratio, of the jet and the main stream considering the effect of the boundary layer thickness was shown to be a useful parameter to explain the jet behavior.     

Interaction of a supersonic flow with a transverse jet injected through a circular aperture in a plate

A flow pattern created by the interaction of a supersonic flow with a transverse sonic or supersonic jet injected normally to the direction of the main flow through a circular aperture in a plate is considered. The pressure rises in front of the jet owing to the retarding action of the incident flow. The boundary layer building up on the wall in front of the injection nozzle is accordingly detached. The flow pattern in the region of interaction between the jet and the external flow is illustrated in Fig. 1. The three-dimensional zone of detachment thus formed deflects the incident flow from the wall, and in front of the jet a complicated system of sharp jumps in contraction develops. A three-dimensional system of jumps also develops in the jet itself.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No, 5, pp. 193–197, September–October, 1970.     

Interaction of a transverse gas jet with supersonic flow in a dihedral

The results of an experimental investigation of supersonic flow at the Mach number M₁=3 past a transverse gas jet flowing from an orifice in the edge of a dihedral with a linear angle of 90° are presented. The Mach number of the jet was varied from 1 to 3, and the ratio of the total pressure in the jet to the free stream pressure from 90 to 760. Visualization of the flow near the faces of the dihedral revealed the existence of internal lines of flow convergence and divergence in the region of three-dimensional separated flow, which indicates the presence of complex vortex structures. The dependence of the dimensions of the separated flow zone and the characteristic pressures in it on the jet parameters is explored.Moscow. Translated from Izvestiya Rossiiskoi Akademii Nauk, Mekhanika Zhidkosti i Gaza, No. 6, pp. 161–165, November–December, 1994.     

Mixing of a supersonic stream and a transverse jet injected through a circular hole in a plate

An experimental investigation is conducted of the propagation and mixing of a transverse sonic jet injected into a supersonic gas stream through a circular hole in a plate. The picture of the interaction at the initial section of the injected jet is examined in the majority of papers devoted to this question [1–3]. The aim of this paper is to investigate the mixing of the injected jet with the free stream, and to establish criteria governing the jet insertion and mixing processes.     

Vortical structures behind a transverse jet in a supersonic flow at high jet to crossflow pressure ratios

A three-dimensional supersonic turbulent flow with symmetric normal injection of circular jets from the channel walls is numerically simulated. The initial Favre-averaged Navier–Stokes equations closed by the k–ω turbulence model are solved by an algorithm based on an ENO scheme. The mechanism of the formation of vortical structures due to the interaction of the jet with the free stream is studied for jet to crossflow total pressure ratios ranging from 3 to 50. It is known from experiments reported in the literature that, for n ? 10, mixing of the jet with the high-velocity flow leads to the formation of a pair of vortices and of an additional separation zone near the wall behind the jet. It is demonstrated that the present numerical results are consistent with such findings and that the pressure distribution on the wall ahead of the jet in the plane of symmetry is also in reasonable agreement with available experimental data.     

Numerical simulation of the interaction of a transverse jet with a supersonic flow using different turbulence models

This paper presents a numerical simulation of the flow resulting from transverse jet injection into a supersonic flow through a slot nozzle at different pressures in the injected jet and the crossflow. Calculations on grids with different resolutions use the Spalart–Allmaras turbulence model, the k–ε model, the k–ω model, and the SST model. Based on a comparison of the calculated and experimental data on the wall pressure distribution, the length of the recirculation area, and the depth of jet penetration into the supersonic flow, conclusions are made on the accuracy of the calculation results for the different turbulence models and the applicability of these models to similar problems.     

Numerical study of unsteady compressible flow driven by supersonic jet injected into elliptical cell with small exit hole

The unsteady behavior of flow driven by a jet suddenly injected into an elliptical cell is numerically studied by solving the axisymmetric two-dimensional compressible Navier–Stokes equations. This system is a model of laser ablation of a certain duration followed by a discharging process through the exit hole at the downstream end of the cell. The parameters for the calculations are the exit diameter of the cell, the Mach number and duration of the injected jet. The injected jet becomes a traveling plume approaching the downstream end of the elliptical cell and discharges from the cell through an exit hole. The plume generates and interacts with a shock wave in the elliptical cell. The unsteady flow properties downstream of the cell are found to be attenuated by the combination of the phenomena occurring in the cell and at the exit. Monitoring the velocity at the exit hole is used to clarify the characteristics of the flow and apply them to applications in pulse laser ablation. The results show that the vortex in the plume head with the same radius as the exit diameter (i.e., D_e/D_j = 2.7, where D_e is the exit diameter and D_j is the injected jet diameter) causes a relatively constant velocity at the exit for about 10 μs. In the downstream flow characteristics, the suddenly injected jet makes a single or double peak in the velocity variation outside the cell depending on the combination of parameters. This suggests that a single laser pulse might generate two beams through the exit hole of a cell, which could increase the efficiency of beam generation with the combination of an elliptical cell and the laser ablation. It is also found that the wave form of the variations and their level are roughly determined by the durations of the jet and the exit diameters of the cell exit, respectively. PACS 51.35.+a; 47.40.Nm     

Determination of the base pressure during axisymmetric supersonic jet outflow into a channel

The outflow of an axisymmetric jet into a cylindrical channel of arbitrarily large cross-sectional area is considered. A method is proposed for analysis of the base pressure in the separation zone bounded by the inviscid jet boundary, the channel wall, and the step. New experimental results about the base pressure during jet outflow into a large-diameter channel are presented.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 6, pp. 125–129, November–December, 1973.     

Sonic annular jet in a counterstreaming supersonic flow

When sonic annular jets encounter a supersonic flow, two interaction regimes are possible with open or closed central separation regions. When the flow regimes change, there is an abrupt change in the separation of the shock wave from the nozzle and of the pressure in the central separation region, and hysteresis is also observed. The flow regimes with open central separation region are stationary and can be calculated numerically on the basis of Euler's equations fairly accurately.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 5, pp. 175–180, September–October, 1979.     

Three-dimensional structure of flow in a supersonic underexpanded jet

Translated from Zhurnal Prikladnoi Mekhaniki i Tekhnicheskoi Fiziki, No. 4, pp. 42–47, July–August, 1991.     

Investigation of interaction between a plane transverse gas jet and a supersonic stream

The problem of interaction between a two-dimensional transverse gas jet emerging from a slot on a flat plate and a supersonic stream is considered. Several theoretical methods based on various approaches and physical models have been proposed to determine the characteristics of such a flow. The following fundamental directions can be isolated: a quasi-one-dimensional method [1], use of blast theory [2], and methods based on the equivalence of the effect of the jet and some solid on the external flow [3, 4]. However, the listed computational schemes [1–4] do not permit any clarification of the flow configuration in the jet and in the outer stream (the shock configuration, the jet boundaries, the distribution of the gasdynamic parameters in the flow field, etc.). Extensive experimental investigations of this phenomenon have been carried out simultaneously with the development of the theoretical methods, wherein the flow picture was determined, the pressure distribution was measured in the interaction domain, etc. [5, 6]. A computation method is proposed in this paper which will permit a detailed investigation of the flow structure in the jet and in the outer flow outside the separation region. Underlying the method is a hypothesis verified experimentally: The separating streamline in the mixing layer of the separated boundary layer (the “constant mass∝ line) intersects the jet boundary at the point of maximum jet standoff from the nozzle exit towards the incoming stream.     

Features of separated supersonic flow pulsations ahead of a spike-tipped cylinder

Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, No. 6, pp. 101–108, November–December, 1991.     

Vibrations of a fan jet in running a supersonic jet into a notched obstacle

Some kinds of vibrations of a fan jet are described. A physical model of one kind of self-excited vibrations of the fan jet is formulated. The formulas to calculate the frequencies of self-excited vibrations are given. Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 40, No. 4, pp. 118–124, July–August, 1999.     

Calculation of a supersonic overexpanded jet of an ideal gas issuing into an ambient transonic flow

The results of a numerical investigation of the exhaust of an inviscid axisymmetric jet into an ambient transonic flow in the overexpansion mode are presented. The steady-state flow pattern is obtained during a buildup process by integration of the nonsteady-state equations of gasdynamics using Godunov's finite-difference method.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 4, pp. 155–158, July–August, 1976.The authors are indebted to A. N. Kraiko and M. Ya. Ivanov for useful discussions and their interest in the work.     

DIAMOND PORT JET INTERACTION WITH SUPERSONIC FLOW

Interaction flow field of the sonic air jet through diamond shaped orifices at different incidence angles （10 degrees, 27.5 degrees, 45 degrees and 90 degrees） and total pressures （0.10 MPa and 0. 46 MPa） with a Mach 5.0 freestream was studied experimentally. A 90 degrees circular injector was examined for comparison. Crosssection Mach number contours were acquired by a Pitot-cone five-hole pressure probe. The results indicate that the low Mach semicircular region close to the wall is the wake region. The boundary layer thinning is in the areas adjacent to the wake. For the detached case, the interaction shock extends further into the freestream, and the shock shape has more curvature, also the low-Mach upwash region is larger. The vortices of the plume and the height of the jet interaction shock increase with increasing incidence angle and jet pressure. 90 degrees diamond and circular injector have stronger plume vorticity, and for the circular injector low-Mach region is smaller than that for the diamond injector. Tapered ramp increases the plume vorticity, and the double ramp reduces the level of vorticity. The three-dimensional interaction shock shape was modeled from the surface shock shape, the center plane shock shape, and crosssectional shock shape. The shock total pressure was estimated with the normal component of the Mach number using normal shock theory. The shock induced total pressure losses decrease with decreasing jet incidence angle and injection pressure, where the largest losses are incurred by the 90 degrees, circular injector.