Search

The measurement of the static pressure of the flow inside a supersonic ejector can be achieved by using a thin tube with a radially drilled hole to capture the flow pressure, and which is inserted along the ejector axis. This paper presents a numerical study by CFD permitting to predict the disturbances generated by the presence of the probe in the ejector. Also this study allows guiding the design of the probe, in particular of the capillary tube diameter for the least disturbed measurement. A probe prototype has been built and tested on an ejector test bench. [ABSTRACT FROM AUTHOR]

Numerical investigation is carried out to study the effect of standoff distance and area ratio on mass entrainment of an air–air circular exhaust ejector. Nozzle and mixing tube are the two components of an ejector, and for the present study, circular cross section shape has been chosen. Numerical simulations have been carried out at Reynolds number in the range of 6.85 × 104 and 4.11 × 105. Area ratio is varied between 1.25 < area ratio < 4 and standoff distance is varied from 1Dnz < standoff distance < 4Dnz, where Dnz represent the nozzle exit diameter. It is observed that for the ejector configuration with area ratio as 2, 2.25, and 2.5, the mass entrainment characteristics are nearly independent of standoff distance between 1Dnz to 4Dnz. For ejector configuration with area ratio below 2, mass entrainment decreases with increase in standoff distance. For ejector configuration with area ratio greater than 2.5, mass entrainment increases with increase in standoff distance for the range investigated and has the tendency to taper off beyond 4Dnz for most of the area ratios. Effect of change in mixing tube length is also studied. It is seen that the mass entrainment improves with increase in length up to 8Dnz. Further increase in length does not effect mass entrainment. This study provides important guidelines that can aid in arriving at an optimal design of circular exhaust ejectors. [ABSTRACT FROM AUTHOR]

Steam ejectors, or thermocompressors, are widely used in thermal desalination applications such as Multiple Effect Distillation to reclaim some of the energy discarded in the condensation of vapor from the last effect. Although several empirical models for the entrainment ratio as a metric of performance of the ejectors are available in the literature, large discrepancies are present in their predictions. In the present paper, a physical model for the performance of an ejector is developed, along with an investigation of its off-design performance. [ABSTRACT FROM AUTHOR]

This work aims at providing novel insights into the quantification and the location of the transfers and the irreversibilities within supersonic ejectors, and their connection with the entrainment. In this study, we propose two different and complementary approaches. First of all, recent analysis tools based on momentum and energy tubes (Meyers and Meneveau (2013)) are extended to the present compressible flow context and applied to the mean-flow structure of turbulent flow within the ejector. Furthermore, the transport equation for the mean-flow total exergy is derived and exergy transport tubes are proposed as a tool for the investigation of transport phenomena within supersonic ejectors. In addition to this topological approach, an analysis based on classical stream tubes is performed in order to quantitatively investigate transfers between the primary and the secondary streams all along the ejector. Finally, the present work identifies the location of exergy losses and their origins. Throughout this analysis, new local and cumulative parameters related to transfers and irreversibilities are introduced. The proposed methodology sheds light on the complex phenomena at play and may serve as a basis for the analysis of transport phenomena within supersonic ejectors. For the ejector under consideration, although global transfers are more important in on-design conditions, it is shown that the net gain in exergy of the secondary stream is maximum for a value of the back pressure that is close to the critical back pressure, as irreversibilities due to viscous dissipation are significantly lowered compared to other operating points. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Dalian University of Technology / Dalian Ligong Daxue Xuebao is the property of Journal of Dalian University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A ready-made central strut-based rocket-based combined-cycle (RBCC) engine was numerically investigated in the ejector mode. The flow features in the RBCC inlet and the matching characteristics between the inlet and the embedded rocket during different flight regimes were examined in detail. It was necessary to perform integrated numerical simulations in the ejector mode within considerable pressure far fields around the inlet/exhaust system. The observed flow features and operation characteristics in the RBCC inlet were strongly correlated with the flight conditions, inlet configuration, and operation of the embedded rocket. It was further found that the integrated function status of multiple factors significantly influenced the performance of the RBCC engine in the ejector mode. The two parameters that macroscopically affected the performance most were the air entrainment mass and the drag of the RBCC inlet. To improve these parameters, it is vital to employ an appropriate design of the RBCC inlet and establish the optimal flight trajectory of the flight vehicle. [ABSTRACT FROM AUTHOR]

In this study, it is proposed to lift the no-slip constraint imposed in the Homogenous equilibrium Model (HEM) for two-phase ejector design and analyse its effects on performance. Two models accounting for slip are used: the first, currently available in the literature is due to Moody and the second, developed by the authors is proposed as an alternative. Firstly, in order to avoid the direct computation of the velocity of sound in two-phase flow close to critical conditions, it is proposed to maximise the mass flow rate in the nozzle without recourse to the Mach number, since the computation of this latter in two-phase conditions has not yet gained consensus. Secondly, the introduction of a slip factor accounting for the velocity difference between vapour and liquid phases has allowed achieving remarkable improvements of critical flow computations, especially when using the newly developed approach by the authors. Thirdly a test facility for two-phase ejectors using R134a as refrigerant has been built for further studies. First results have allowed to validate the models predictions of the critical flow over a large interval of operating conditions. Lastly, analysis indicates that neglecting interphase slip may have a significant impact on two-phase ejector design. In this way and under some ejector inlet conditions, the prediction gap between HEM and the new model falls in the range of 13 to 23% in terms of compression ratio and in the range of 33 to 39% for the nozzle throat diameter. [ABSTRACT FROM AUTHOR]

Designing the jet ejector optimally is a challenging task and has a great impact on industrial applications. Three different sets of nozzles (namely, 1, 3, and 5) inside the jet ejector are compared in this study by using numerical simulations. More precisely, dynamics of bubble coalescence and breakup in the multinozzle jet ejectors are studied by means of Computational Fluid Dynamics (CFD). The population balance approach is used for the gas phase such that different bubble size groups are included in CFD and the number densities of each of them are predicted in CFD simulations. Here, commercial CFD software ANSYS Fluent 14.0 is used. The realizable k-ε turbulence model is used in CFD code in three-dimensional computational domains. It is clear that Reynolds-Averaged Navier-Stokes (RANS) models have their limitations, but on the other hand, turbulence modeling is not the key issue in this study and we can assume that the RANS models can predict turbulence of the carrying phase accurately enough. In order to validate our numerical predictions, results of one, three, and five nozzles are compared to laboratory experiments data for Cl2-NaOH system. Predicted gas volume fractions, bubble size distributions, and resulting number densities of the different bubble size groups as well as the interfacial area concentrations are in good agreement with experimental results. [ABSTRACT FROM AUTHOR]

Pulse detonation engines (PDEs) are new exciting propulsion technologies for future propulsion applications. The operating cycles of PDE consist of fuel-air mixture, combustion, blowdown, and purging. The combustion process in pulse detonation engine is the most important phenomenon as it produces reliable and repeatable detonation waves. The detonation wave initiation in detonation tube in practical system is a combination of multistage combustion phenomena. Detonation combustion causes rapid burning of fuel-air mixture, which is a thousand times faster than deflagration mode of combustion process. PDE utilizes repetitive detonation wave to produce propulsion thrust. In the present paper, detailed review of various experimental studies and computational analysis addressing the detonation mode of combustion in pulse detonation engines are discussed. The effect of different parameters on the improvement of propulsion performance of pulse detonation engine has been presented in detail in this research paper. It is observed that the design of detonation wave flow path in detonation tube, ejectors at exit section of detonation tube, and operating parameters such as Mach numbers are mainly responsible for improving the propulsion performance of PDE. In the present review work, further scope of research in this area has also been suggested. [ABSTRACT FROM AUTHOR]

Computational solutions of the Reynolds-averaged Navier-Stokes equations have been used to understand the performance of thrust-augmenting ejectors for vertical and short takeoff and landing aircraft. These solutions show how ejector performance depends on the principle ejector design parameters, including the ejector inlet area, the diffuser exit area, and the length of the ejector duct, as well as the type and configuration of the primary jet nozzles. It is concluded that there is a relatively sharp peak in ejector performance that occurs over a relatively narrow range of inlet area ratios where the character of the flow changes from duct flow to free jet flow. Both the peak performance and the optimum inlet area ratio are seen to increase with the length of the ejector duct. Both increasing the jet entrainment rate and the addition of wall jets are shown to enhance the performance of short aircraft ejectors. [ABSTRACT FROM AUTHOR]

The article describes the innovative solutions of power, heating and cooling generation utilizing low- or medium-grade heat sources. The proposed technology based on the well-known irreversible Brayton cycle and the revolutionary Maisotsenko cycle (M-cycle) operates at atmospheric or sub-atmospheric pressures. Such energetic systems are simple and reliable and utilize moisture-saturated air as a working fluid. The ejector replacing the mechanical compressor in the Brayton cycle system allows increasing the cycle work by three to five times at the constant airflow. At the same time, the utilized heat serves for simultaneous heating and cooling production that makes the system economically viable and environmentally friendly with the increased integral performance. For system's performance improvement, the schematic and the cycle were upgraded allowing the off-the-shelf components to be employed and replace the electrically driven fan with fluidic jet-fan that served for energy saving of the innovative turbo-ejector system operation. [ABSTRACT FROM AUTHOR]

Rocket-based combined cycle (RBCC) Engine can significantly reduce the amount of onboard oxidizer required. This will decrease the weight of the vehicle and improve the performance of the RBCC engine. In this short communication, an idealized thermodynamic cycle analysis is carried out to evaluate the thrust performance of RBCC engine for the saturated supersonic regime. The thrust for the rocket-ejector mode not only depends on the inducted air flow rate, but also depends on the thermal efficiency. Initially, the results show that the engine thrust grows asymptotically with ejecting ratio, then reaches a maximum, and finally reduces rapidly for a given primary stream conditions. The optimum ejecting ratio at which the value of the thrust attains a maximum is also presented. [ABSTRACT FROM AUTHOR]

Ejectors produce a pumping effect based on high speed jet entrainment but data on the development of mixing in steam ejectors with condensation effects is not available. In the present work, the mixing region generated downstream of an axisymmetric supersonic steam ejector nozzle is surveyed using a pitot pressure probe. Steam was delivered to the nozzle at a stagnation temperature of 142°C and at a stagnation pressure of either 270 or 300kPa. The nozzle had an exit diameter of 13.6mm and it produced a flow of steam at approximately 1150m/s, resulting in high compressibility mixing conditions; the convective Mach number was approximately 1.5. Pitot pressure profiles at positions 1, 25, 50, and 70mm downstream of the nozzle exit were obtained within a steam vapour-filled test section at a pressure of approximately 3kPa. The data demonstrates that the jet was slightly over-expanded at these conditions with non-uniformities in the pitot pressure data apparent at the 25mm station. The free shear layer growth rate deduced from the pitot pressure measurements was δ ′ ≈ 0.06 ± 0.02 and this value agrees with established empirical results for compressible, planar mixing layers. There are reasonable prospects for the development of reliable engineering models for secondary stream entrainment in ejector applications based on existing correlations for compressible mixing. [ABSTRACT FROM AUTHOR]

Abstract: Supersonic ejectors are simple mechanical components, which generally perform mixing and recompression of two fluid streams. Ejectors have found many applications in engineering. In aerospace engineering, they are used for high altitude testing (HAT) of a propulsion system by reducing the pressure of a test chamber. It is composed of three major sections: a vacuum test chamber, a propulsive nozzle, and a supersonic exhaust diffuser. This paper aims at the improvement in HAT facility by focusing attention on reducing exhaust back flow into the test chamber, since alteration of the backflow appears as one of the potential means of significantly improving its performance. The simplest backflow-reduction device was an orifice plate at the duct inlet, which would pass the jet and entrained fluid but impede the movement of fluid upstream along the wall. Results clearly showed that the performance of the ejector–diffuser system was improved for a certain range of system pressure ratios, whereas the orifice plate was detrimental to the ejector performance for higher-pressure ratios. It is also found that, there is no change in the performance of diffuser with an orifice at its inlet, with respect to its pressure recovery. Hence, an appropriately sized orifice system should produce considerable improvement in the ejector–diffuser performance in the intended range of pressure ratios. [Copyright &y& Elsevier]

An abrupt increase in duct cross-section is often found in pressure-reducing devices, valves of internal-combustion engines, flow control devices in pipe systems of power plants, launch tubes of the ballistic ranges, thrust augmentation systems for cruise missiles, zero secondary flow ejectors, etc. The objective of this study is to revisit the classical base flow fields in a wall-bounded supersonic flow past a sudden expansion, to study and exploit their dependence on the size of the enlarged part – termed as the base size. Two-dimensional numerical simulations are performed for a nozzle flow, which is suddenly expanded in a larger rectangular channel. Five different turbulence models have been utilized in this study. Flow determination near the base is influenced by the proper selection of the turbulence model. The numerical solutions are compared with available experimental data and good agreement is achieved with renormalization group k–ε turbulence model. This investigation is concerned with the determination of the base size, for which the jet characteristics and the base pressure become independent of the size of the enlarged part. For a given duct, base pressure tends to a minimum for a particular pressure ratio. In this study, the authors have been able to link the jet characteristics to the base size by both analytical and numerical methods. This has led to the conclusion that for a constant driving pressure, the base pressure asymptotically decreases when the base size is increased up to a critical value, and it becomes independent of the base size thereafter. It is believed that the results of this study can provide a better understanding of the wall-bounded supersonic flow past a sudden expansion. The relevance of the present observations in some of the engineering applications is also discussed. [ABSTRACT FROM PUBLISHER]

Numerical simulations of a single ejector driven by one- and two-pulse detonation engines (PDE) were performed to investigate the thrust augmentation mechanism. The systems of conservative laws of inviscid fluid combined with the one-step chemical reaction model are discretized in Cartesian coordinates using the high resolution hybrid Roe/HLL scheme and adaptive mesh refinement method, and integration in time is performed with a second-order Runge-Kutta method. Our results described the propagation processes of both primary detonation of PDE and secondary induced detonation wave inside the ejector. For a single detonation tube, the detonation gases were expelled from the ejector inlet first, then, a large amount of ambient air is entrained into the ejector with the development and propagation of detonation wave along the ejector. However, for the two-detonation tube case, both the level and duration of expelled flow increase due to the interaction of shocks near the intersection of tubes and ejector, which causes less ambient air to be entrained into the ejector and leads to a decrease of ejector thrust augmentation. Our results agree well with corresponding experimental results. [ABSTRACT FROM AUTHOR]

Abstract: Experimental studies were performed in order to improve the understanding of the performance of ejector driven by an air-breathing pulse detonation engine (PDE) with a convergent nozzle. This research utilized a gasoline-air PDE at four different operating frequencies of 8Hz, 10Hz, 12Hz and 15Hz. The performance of PDE-ejector was quantified by thrust measurements. The effects of single ejector length and axial location on thrust augmentation were investigated. It was found that the single ejector with L/D of 2 showed the best performance and the maximum thrust augmentation occurred at a downstream placement of +1 tube diameter. The performances of two-stage and three-stage ejectors were also investigated. The results indicated that both the overlap ratio and the flow area between two stages should not be too large. The performance of the two-stage ejector was not as sensitive as single-stage ejector to axial position in current conditions. The three-stage ejector behaved better than the two-stage ejector but worse than the single-stage ejector in this work. A maximum thrust augmentation of 1.8 was obtained with an L/D of 2 at a downstream placement of +1 position and 15Hz operating frequency. [Copyright &y& Elsevier]

Abstract: The following cold-flow study examines the interaction of the diffracted shock wave pattern and the resulting vortex loop emitted from a shock tube of various geometries, with an ejector having a round bell-shaped inlet. The focus of the study is to examine the performance of the ejector when using different jet geometries (primary flow) to entrain secondary flow through the ejector. These include two circular nozzles with internal diameters of 15mm and 30mm, two elliptical nozzles with minor to major axis ratios of a/b =0.4 and 0.6 with b =30mm, a square nozzle with side lengths of 30mm, and two exotic nozzles resembling a pair of lips with axis ratios of a/b =0.2 and 0.5 with b =30mm. Shock tube driver pressures of P 4 =4, 8, and 12bar were studied, with the pressure of the shock tube driven section P 1 being atmospheric. High-speed schlieren photography using the Shimadzu Hypervision camera along with detailed pressure measurements along the ejector and the impulse created by the ejector were conducted. [Copyright &y& Elsevier]

Abstract: A theoretical analysis of a variable area rocket based combined cycle engine with and without simultaneous mixing and combustion is presented. The flowfield is solved using a steady, quasi-one-dimensional, inviscid control volume formulation with combustion effects included via a generalized equilibrium calculation. Compression augmentation is shown to be sensitive to the equivalence ratio within the primary rocket chamber, where ejector section performance is greatest at both low and high equivalence ratios but near a minimum at stoichiometric conditions. The thrust generated by the RBCC engine compared to that generated by the same rocket in isolation can be increased by as much as 12% at constriction ratios of between 45% and 50%. Thrust augmentation is also shown to vary with equivalence ratio, where for a fixed geometry the maximum thrust is generated at equivalence ratios slightly below unity. [Copyright &y& Elsevier]

A mathematical model of the adjustable ejector was established and the flow of the adjustable ejector was simulated by FLUENT on different spindle positions. The experimental results indicate that the axial pressure of an adjustable ejector increases linearly in the constant area mixing section, sharply in the beginning of diffuser section and then slowly in the other sections of diffuser. The velocity of flow in the mixing section differs significantly at the axis and boundary. The movement of spindle into the nozzle makes the position of shock wave upstream and motive flow rate decreases. [ABSTRACT FROM AUTHOR]

The objective of the present study is to analyse the transient flow through the vacuum ejector system with the help of a computational fluid dynamics method. An attempt is made to investigate the interesting and conflicting phenomenon of the continuous entrainment into the primary stream with limited mass supply from the secondary chamber. The results obtained show that the one and only condition in which a continuous mass entrainment can be possible in such types of ejectors is the generation of a recirculation zone near the primary nozzle exit. The flow in the secondary chamber attains a state of dynamic equilibrium of pressure at the onset of the recirculation zone. A steady flow assumption in such ejector systems is valid only after the dynamic equilibrium state. [ABSTRACT FROM AUTHOR]

Coanda effect is the phenomena in which a jet flow attaches itself to a nearby surface and remains attached even when the surface curves away from the initial jet direction. In free surroundings, a jet of fluid entrains and mixes with its surroundings as it flows away from a nozzle. When a surface is brought close to the jet, this restricts the entrainment in that region. As flow accelerates to try balance the momentum transfer, a pressure difference across the jet results and the jet is deflected closer to the surface - eventually attaching to it. [ABSTRACT FROM AUTHOR]

A reaction-drive rotor configuration including an ejector nozzle is studied to determine possible exhaust-jet velocity reduction for the purpose of noise suppression. A vortex-wake rotor model is compared with an experimental rotor test, determining the model validity for a hovering rotor. A two-dimensional computational fluid dynamic model of an ejector flow is compared with an experimental ejector-nozzle test to determine the appropriate grid coarseness and turbulence model relevant to lift and drag predictions supporting the hovering-rotor aerodynamic model. The reaction-drive-rotor tip-jet-ejector nozzle geometry is sized by the analysis method put forward here, implementing coupled rotor aerodynamic, reaction-drive tip-jet-ejector thermodynamic, and computational fluid dynamic models. A performance version of the proposed analysis method is developed to characterize this rotor configuration over a range of blade collective pitch angles operating in a hovering-flight condition. [ABSTRACT FROM AUTHOR]

A parametric study into the integration of a pulse detonation engine (PDE) with an ejector was performed. High- speed shadowgraph visualizations of the flow inside the two-dimensional ejector provided a qualitative method of determining the performance of the integrated system. The performance was observed to be sensitive to the inlet geometry of the ejector as well as its axial position relative to the exhaust plane of the PDE. Significant levels of entrainment were obtained when the ejector's inlet was contoured, whereas flow separation reduced entrainment efficiency in the ejector with a straight thin inlet lip. Also, the high-speed shadowgraph visualizations showed that the entrainment produced by the PDE-ejector system could be modified by the presence of an exhaust nozzle on the PDE. Qualitative analysis of the high-speed images using the coherent structure velocimetry method was conducted to obtain pseudovelocity information. [ABSTRACT FROM AUTHOR]

The problem considered in this study is to evaluate efficiently displacement derivatives using global finite differences. Given the displacements for an initial design, the displacements for various modified designs are evaluated by the recently developed combined approximations method. Calculations of finite difference sensitivity coefficients are demonstrated for static problems and eigenproblems. The presented solution procedure is easy to implement, efficient, and can be used to calculate derivatives for various designs where the exact displacements are not known. Some numerical examples show that the accuracy of the results is similar to the accuracy obtained by finite difference calculations based on exact analysis. [ABSTRACT FROM AUTHOR]

The present study deals with the visualization of the air flow inside a supersonic ejector. Our attention is more precisely focused on the choked flow phenomenon which occurs along the mixing chamber of the secondary nozzle and which can be visualized by CFD. laser tomography visualizations are used to validate the CFD model. The evolution of flow configuration in the ejector with the primary stagnation pressure is examined both in the case of zero secondary flow and in the case of free entrainment of induced air. [ABSTRACT FROM AUTHOR]

Assesses the legitimacy of using methods based on use of nomograms that correlate the ejection factor with the degree of expansion of the ejecting gas and degree of compression of the ejected gas for systems with thermophysical properties different from the vapor-air mixtures for which it is recommended. Simulation of the compression in the converging and diverging diffuser sections by two successive compressors.

Deals with a study which discussed the ejector wall pressure and temperature measurements based on photoluminescence. Factor to consider when documenting pressure patterns on an ejector wall; Indicator of ejector performance characteristics; Importance of correcting for pressure-sensitive paint temperature sensitivity.

The jet-pump refrigerator cycle offers a low-capital-cost solution for utilizing low-grade waste heat in the production of cooling for buildings and process refrigeration. The heart of the jet-pump refrigerator is an ejector, the performance of which strongly determines the thermal efficiency of the cycle. This paper describes and evaluates the results of an experimental investigation into the operation of ejectors primarily for use in jet-pump refrigerators. The construction of a steam–steam ejector test facility and experimental method are described. Experimental results are provided concerning the effects of primary nozzle exit position within the mixing–entrainment section, primary nozzle exit and diffuser throat areas. The causes and effects of flow instability under conditions of high secondary pressure ratio are also discussed and methods of increasing the critical condenser pressure are identified and rated in order of effect. [ABSTRACT FROM AUTHOR]

Effects accompanying the propagation of the high-pressure axially symmetric gas jet in a tube with permeable walls and closed ends are investigated experimentally. The patterns of smoke visualization of the flows outside the tube, the fields of static pressures along the tube, and the concentration distributions of the jet material along the outer and inner tube walls, depending on the conditions of jet injection are found. The schematic of media flows inside, outside, and through the wall of the permeable tube, in which combining the functions in a form of the jet mixer-ejector in the inner space and burner facility on the outer wall is implied, is suggested. [ABSTRACT FROM AUTHOR]

An analytical model to predict the primary stagnation pressure that starts an annular injection supersonic ejector is presented. If the length of the mixing chamber is longer than the critical length, the starting pressure increases proportionally to the mixing chamber length, which differs from conventional ejectors using central injection. To describe the dependency of the starting pressure on the mixing chamber length, we assume that the ejector starts when the exiting supersonic primary flow reaches the second throat. In the present model, we use a subsonic mixing model to calculate the secondary flow pressure in the mixing chamber. Applying the obtained pressure as a back pressure condition, the distance that the supersonic primary flow develops is calculated. Comparing the distance to the mixing chamber length, we derive a minimum pressure requirement diagram that accurately predicts the starting pressure and hysteresis for a given geometry. [ABSTRACT FROM AUTHOR]

An experimental investigation is described in which a simple speaker-driven jet was used as a pulsed thrust source (driver) for an ejector configuration. The objectives of the investigation were twofold. The first was to expand the experimental body of evidence showing that an unsteady thrust source, combined with a properly sized ejector generally yields higher thrust augmentation values than a similarly sized, steady driver of equivalent thrust. The second objective was to identify characteristics of the unsteady driver that may be useful for sizing ejectors, and for predicting the thrust augmentation levels that may be achieved. The speaker-driven jet provided a convenient source for the investigation because it is entirely unsteady (i.e., it has no mean velocity component) and because relevant parameters such as frequency, time-averaged thrust, and diameter are easily variable. The experimental setup will be described, as will the two main measurements techniques employed. These are thrust and digital particle imaging velocimetry of the driver. It will be shown that thrust augmentation values as high as 1.8 were obtained, that the diameter of the best ejector scaled with the dimensions of the emitted vortex, and that the so-called formation time serves as a useful dimensionless parameter by which to characterize the jet and predict performance. [ABSTRACT FROM AUTHOR]

Several corrections to the article that were published in the July 2006 to September 2006 issue are presented, including "Simplified Approach of Jet Aerodynamics With a View to Acoustics," Experimental Investigation of an Annular Injection Supersonic Ejector," and "Tension Buckling in Shear-Flexible Composite Beams."