Download or read book Experimental and Numerical Investigation of Supersonic Impinging Jets written by F. S. Alvi and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental and Numerical Study of A Supersonic Jet Shock Wave Structure written by and published by . This book was released on 2002 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The investigation of the shock-wave structure and numerical characteristics of supersonic-jet shear layer is of great importance due to numerous applications of supersonic jets in aerospace engineering. In the present work, a detailed study of a supersonic non-isobaric jet aimed at validation and further development of numerical algorithms for jet flow prediction has been carried out. The difficulties in numerical simulation of supersonic non-isobaric jets stem from the necessity of accurate resolution of various flow scales and from the occurrence of multiple shock waves and subsonic pockets interacting with each other.

Download or read book Experimental Investigation of Supersonic Impinging Jets in Stovl Configuration written by Kartik G. Iyer and published by . This book was released on 1999 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Numerical Investigation of Supersonic Jet Interaction for Finned Bodies written by and published by . This book was released on 2000 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: A detailed numerical investigation of the interaction between a lateral jet and the external flow has been performed for a variety of missile body geometries. These include non-finned axisymmetrical bodies and finned bodies with either strakes or aft-mounted tail fins. The computations were performed at Mach numbers 2, 4.5, and 8. To obtain the numerical results, both Reynolds- averaged Navier-Stokes and Euler techniques were applied. The computational results were compared with results from a previously published wind tunnel study that consisted primarily of global force and moment measurements. The results show significant interactions of the jet-induced flow field with the fin surfaces, which produce additional effects compared with the body alone. In agreement with the wind tunnel study, in some cases the presence of lifting surfaces resulted in force and/or moment amplification of the jet interaction with the missile surfaces. The results indicate deamplification of the jet force at Mach 2 for all three bodies. Amplification of the jet force was also observed for high Mach numbers, particularly for the body with strakes. For the results examined here, there were only minor differences in the global force and moment predictions when viscous or inviscid techniques were used. The dependence of the interaction parameters on angle of attack and jet pressure was well predicted by both methods. The numerical techniques showed good agreement with the experiments at supersonic Mach numbers but only fair agreement for the hypersonic, Mach 8 case.

Download or read book Numerical and Experimental Study of Jet Impingement Or Interaction Effects at Hypersonic and Supersonic Speeds written by C. Y. Wang and published by . This book was released on 1991 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Numerical Investigation of Supersonic Reacting Hydrogen Jets in a Hot Air Co flow written by Daniel Gaffie and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Numerical Investigation of the Supersonic Flow Around a Longitudinal Cylinder with Different Surface Roughness Conditions written by Edgar Augenstein and published by . This book was released on 1999 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental Characterization of Supersonic Dual Impinging Jet Flows written by Vikas Nataraj Bhargav and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The impinging jet flowfield observed during take-off and landing of a STOVL aircraft is known to be associated with several adverse effects such as strong acoustic emission, unsteady structural loads, loss of engine efficiency due to hot gas ingestion, thermal stresses on the deck surface, and loss of lift. This flowfield has been well studied from the standpoint of characterizing the induced lift forces and moments caused by fountain flows, unique to such a flowfield. However, in the scenario of two such jets operating in tandem where properties are influenced by jet-jet interaction and coupling, are relatively unknown. Also, there is a lack of understanding of the consequences of difference in the momentum-flux and temperature of the two jets on the flow and acoustic properties. Therefore, the fundamental goal of this study is to systematically assess how different parameters such as momentum-flux and temperature affect the flow and acoustic properties of supersonic dual impinging jets. Thus, the three objectives of this study are: (1) How are the characteristics of supersonic dual impinging jets different from those of a supersonic single impinging jet? (2) What is the effect of relative momentum-flux between the two jets, on the aeroacoustic characteristics of supersonic dual impinging jets? (3) What is the effect of relative temperature, on the aeroacoustic characteristics of supersonic dual impinging jets? To address the first objective, experimental investigation of the flowfield associated with two, under-expanded impinging jets operating at a Nozzle Pressure Ratio (NPR) of 2.65, discharged from identical converging nozzles with an exit diameter of 25.4 mm, is performed. Comparisons with a single impinging jet, operating at the same conditions are provided through shadowgraph flow visualizations, nearfield acoustics, and surface pressure measurements. Fountain flow produced by the interaction of wall jets, a unique feature of dual impinging jets, is found to be relatively strong at short impingement heights and contributed to additional loads on the ground surface. Overall flow unsteadiness in dual jets is less than that in a single jet at conditions involving resonance and the fountain upwash plays an important role in the process. Although the feedback mechanism that drives the resonance in both impinging jet configurations is similar and the corresponding instability mode shapes are retained, there are differences in the strengths of the instability modes between the two configurations. To address the second objective, flowfield is characterized by systematically varying the relative jet momentum-flux between the jets. A converging and converging-diverging (CD) nozzle pair, with identical throat and exit diameters, respectively, is employed during the study. The CD (right) nozzle is held at a fixed over-expanded nozzle pressure ratio (NPR) of 3, and the momentum flux of jet from converging (left) nozzle is varied by changing its expansion ratio (ER). Schlieren flow visualization and ground plane surface pressure measurements indicate that the fountain flow position and strength exhibit a strong dependence on the jet momentum flux and a weak dependence on the impingement height. Further, an increase in momentum of the left jet causes the resonance in the right jet to lose its strength and its influence on the unsteadiness of the left jet, owed to the proximity of the fountain flow to the resonating jet. The presence of fountain upwash is found to alter the symmetry of streamlines, shear layer growth characteristics, and turbulent kinetic energy of the right jet. Under certain conditions, the fountain is close enough to significantly interact with the right jet and change the characteristics of the inner shear layer. Thereby, the processes constituting the feedback mechanism are notably altered and culminates in a weaker resonance. To address the third objective, the flowfield is characterized by systematically varying the relative jet temperature between the jets by increasing the temperature of only one of the jets (right). The NPR of the two jets are held fixed at conditions same as those used for the second objective. Qualitative visualization of the flowfield suggests that the left jet and fountain regions remain nearly unaffected by the right jet temperature. However, a corresponding increase in the jet velocity occurs in the right jet. Both the fountain position and its strength are independent of relative jet temperature and a strong function of the jet momentum flux. The increase in jet temperature also results in additional noise in the nearfield and increased unsteadiness on the impingement surface, although the latter is limited to short impingement heights and the region close to the right jet. At higher temperatures, short impingement heights are found to be more susceptible to resonance, with the chief source of resonance originating in the heated jet. At a fixed impingement height, while the jet instability mode shapes are retained, the corresponding impingement tones in the heated jet experience a systematic increment in frequency with rise in temperature. A detailed study of the velocity field suggest that, for a pair of jets at a given relative jet momentum flux, their fountain upwash could contribute to increased unsteadiness in the region around the nozzle (under-surface of the aircraft) at higher jet temperatures. The present experimental study significantly enhances the understanding of the impinging jet flowfield and its associated impacts on the parent aircraft, noise field and nearby structures. From an engineering standpoint, the results from this study will help inform aerodynamicists and structural engineers about the consequences of multi-jet-impingement configurations in STOVL applications. This is done through a systematic characterization of several parameters, which would provide the design guidelines. The three key findings of this study are: (1) Dual impinging jet flow and acoustic fields are strongly influenced by the fountain flow; (2) Fountain strength and placement relative to the jets, plays an important role in influencing the ground induced adverse effects. This in turn depends on the momentum of the jets; (3) Jet temperature can also worsen these effects, although this is a weaker factor than jet momentum From a scientific stand point, the results from this study provide a high fidelity database for the validation of numerical tools on dual impinging jet configuration. Furthermore, the present study provides the baseline data to help study flow and noise control techniques for dual impinging jets.

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Jet in Supersonic Crossflow written by Mingbo Sun and published by Springer. This book was released on 2019-02-18 with total page 284 pages. Available in PDF, EPUB and Kindle. Book excerpt: Based on research into jets in supersonic crossflow carried out by the authors’ team over the past 15 years, this book summarizes and presents many cutting-edge findings and analyses on this subject. It tackles the complicated mixing process of gas jets and atomization process of liquid jets in supersonic crossflow, and studies their physical mechanisms. Advanced experimental and numerical techniques are applied to further readers’ understanding of atomization, mixing, and combustion of fuel jets in supersonic crossflow, which can promote superior fuel injection design in scramjet engines. The book offers a valuable reference guide for all researchers and engineers working on the design of scramjet engines, and will also benefit graduate students majoring in aeronautical and aerospace engineering.

Download or read book Active Control of Supersonic Impinging Jets Using Supersonic Microjets written by Farrukh S. Alvi and published by . This book was released on 2005 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive experimental investigation on the use of microjets for the control of supersonic impinging jets was conducted under this research program. Supersonic impinging jets occur in many applications including in STOVL aircraft where they lead to a highly oscillatory flow with very high unsteady loads on the nearby aircraft structures and the landing surfaces. Prior research has shown that microjets, placed around the main jet periphery, are very effective in reducing the flow unsteadiness and the associated dynamic loads. In the present work, our goal was to better understand the physical properties of supersonic impinging jets through detailed experiments and to develop optimal open and closed-loop control strategies in order to produce efficient control over the range of conditions impinging jet-related problems are significant.

Download or read book NASA Technical Memorandum written by and published by . This book was released on 1994 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Numerical Studies of Supersonic Coanda Wall Jets written by H. D. Kim and published by . This book was released on 2000 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental and Theoretical Studies of Axisymmetric Free Jets written by and published by . This book was released on 1959 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Some experimental and theoretical studies have been made of axisymmetric free jets exhausting from sonic and supersonic nozzles into still air and into supersonic streams with a view toward problems associated with propulsive jets and the investigation of these problems. For jets exhausting into still air, consideration is given to the effects of jet Mach number, nozzle divergence angle, and jet static-pressure ratio upon jet structure, jet wavelength, and the shape and curvature of the jet boundary. Studies of the effects of the ratio of specific heats of the jets are included as are observations pertaining to jet noise and jet simulation. For jets exhausting into supersonic streams, an attempt has been made to present primarily theoretical curves of the type that may be useful in evaluating certain jet interference effects and in formulating experimental studies. The primary variables considered are jet Mach number, free-stream Mach number, jet static-pressure ratio, ratio of specific heats of the jet, nozzle exit angle, and boattail angle. The simulation problem and the case of a hypothetical hypersonic vehicle are examined. A few experimental observations are included.

Download or read book Numerical Investigation of a Transverse Jet for Supersonic Aerodynamic Control written by Steven W. Clark and published by . This book was released on 1992 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Experimental computational Investigation of Supersonic Jet in Subsonic Compressible Flow written by D. Chocinski and published by . This book was released on 1997 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of a Supersonic Gas Jet Impinging Into a Liquid written by Richard Bivins Countess and published by . This book was released on 1968 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: