Mass Injection and Jet Flow Simulation Effects on Transonic Afterbody Drag PDF Download
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Author: Wladimiro Calarese
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 184
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Book Description
An experimental investigation has been performed to determine the effects of boattail injection and jet flow simulation on the afterbody drag of a slender body of revolution in the transonic regime at zero angle of attack, such as engine nacelles and boattailed afterbodies with isolated engines. A correlation between sting and jet diameter has been established. The jet plume and the nozzle pressure ratio simulators have been found appropriate and useful as a testing technique. Boattail mass injection usually produces a drag coefficient reduction and is more effective at high nozzle pressure ratios. Boattail injection is more effective if used in regions of separated flow. (Author).
Author: Wladimiro Calarese
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 184
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Book Description
An experimental investigation has been performed to determine the effects of boattail injection and jet flow simulation on the afterbody drag of a slender body of revolution in the transonic regime at zero angle of attack, such as engine nacelles and boattailed afterbodies with isolated engines. A correlation between sting and jet diameter has been established. The jet plume and the nozzle pressure ratio simulators have been found appropriate and useful as a testing technique. Boattail mass injection usually produces a drag coefficient reduction and is more effective at high nozzle pressure ratios. Boattail injection is more effective if used in regions of separated flow. (Author).
Author: L. L. Galigher
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 144
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Book Description
An experimental program was conducted to investigate the interaction effects which occur between the nozzle exhaust flow and the external flow field associated with isolated nozzle afterbody configurations at transonic Mach numbers. Pressure data were obtained from three afterbody geometries with boattail angles of 10, 15, and 25 deg at Mach numbers from 0.6 to 1.5 at zero angles of attack and sideslip. Cold (High-pressure air) and hot (Air/ethylene combustion) jet test techniques were used to simulate and duplicate, respectively, the nozzle exhaust flow for a sonic jet installation. Nozzle exhaust temperature was varied from 540 to approximately 2,900 R. The most significant results pertain to those effects on boattail pressure drag caused by exhaust plume temperature and flow asymmetry (Model support strut induced). The differences obtained in boattail pressure drag between the cold jet simulation and hot jet duplication results were significant at nozzle pressure ratios representative for turbofan and turbojet engines at subsonic Mach numbers. Adjusting the cold jet nozzle pressure ratio to correct for changes in the exhaust plume specific heat ratio with temperature did not account for the differences observed. Flow asymmetry effects were Mach number and nozzle pressure ratio dependent and increased in severity as the boattail angle was increased.
Author: W. L. Peters
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 50
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Book Description
The objective of this investigation was to isolate those parameters defined as jet mixing effects on afterbody drag in an effort to develop a method of correcting or simulating the effects of jet temperature in wind tunnel experiments. Data used in the investigation were obtained from experiments conducted in the AEDC Aerodynamic Wind Tunnel (1T) with a strut-mounted model at free-stream Mach numbers from 0.6 to 1.2. Integrated afterbody pressure drag coefficient data were acquired for three nozzle area ratios (1.0, 1.24, and 2.96) using various unheated jet exhaust gas compositions that allowed a variation in gas constant from 55 to 767 ft/lbf/lbm-deg R. Jet mixing effects on afterbody drag coefficient produced by varying jet gas constant and nozzle area ratio at nozzle design pressure ratio, and the drag effects resulting from variations in nozzle pressure ratio at certain overexpanded jet conditions were observed to be similar functions of mass flux ratio. A simple experimental method has been proposed to allow corrections of afterbody drag coefficient data obtained in the wind tunnel (using an ambient temperature air jet) for the effects of jet gas constant. By inference, a similar drag correction can be obtained for the combined effect of gas constant and temperature, assuming their product defines the effects on drag produced by variations in either property. (Author).
Author: Linwood W. McKinney
Publisher:
ISBN:
Category :
Languages : en
Pages : 24
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Book Description
A wind-tunnel investigation has been made on modified-square and circular cylinders to determine the effects of fineness ratio and Reynolds numbers on the crosswind drag characteristics. Fineness ratios from 2 to 14 were investigated over a Reynolds number range from approximately 300,000 to 1,650,000 which corresponded to Mach numbers from 0.057 to 0.377.The result of the investigation show that at supercraft Reynolds numbers the drag coefficient of the circular cylinder increases with increasing Reynolds number for all fineness ratios but at low fineness ratios this effect is considerably less than at higher fineness ratios. For circular cylinders in the high fineness-ratio range there is a reduction in drag as the fineness ratio is decreased except for Reynolds numbers of 900,000 and 1,000,000, whereas at low fineness ratios the opposite trend generally occurs. The addition of hemispherical ends to the circular cylinder gave a substantial decrease in drag at a fineness ratio of 3.27 but the effect was negligible at fineness ratios of 5.27 and 10. The finite-length modified-square cylinder gave the reduction in drag over the two-dimensional modified-square cylinder for the complete range of test Reynolds numbers with the lowest fineness ratio giving the lowest drag at Reynolds numbers above 3O0,OOO.
Author: James M. Cubbage
Publisher:
ISBN:
Category : Cone
Languages : en
Pages : 38
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Book Description
Author: Gino Sovran
Publisher: Springer Science & Business Media
ISBN: 1468484346
Category : Technology & Engineering
Languages : en
Pages : 381
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Book Description
These Proceedings contain the papers and oral discussions presented at the Symposium on AERODYNAMIC DRAG MECHANISMS of Bluff Bodies and Road Vehides held at the General Motors Research Laboratories in Warren, Michigan, on September 27 and 28, 1976. This international, invitational Symposium was the twentieth in an annual series, each one having been in a different technical discipline. The Symposia provide a forum for areas of science and technology that are of timely interest to the Research Laboratories as weIl as the technical community at large, and in which personnel of the Laboratories are actively involved. The Symposia furnish an opportunity for the exchange of ideas and current knowledge between participating research specialists from educational, industrial arid governmental institutions and serve to stimulate future research activity. The present world-wide energy situation makes it highly desirable to reduce the force required to move road vehicles through the atmosphere. A significant amount of the total energy consumed for transportation is expended in overcoming the aerodynamic resistance to motion of these vehicles. Reductions in this aerodynamic drag can therefore have a large impact on ground transportation energy requirements. Although aerodynamic development work on road vehides has been performed for many years, it has not been widely reported or accompanied by much basic research.
Author:
Publisher:
ISBN:
Category : Drag (Aerodynamics)
Languages : en
Pages :
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Book Description
Author: Dennis R. Jenkins
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 712
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Book Description
1. A new science / 2. A hypersonic research airplane / 3. Conflict and innovation / 4. The million-horsepower engine / 5. High range and dry lakes / 6. Preparations / 7. The flight program / 8. The research program.
Author: Wolf-Heinrich Hucho
Publisher: Elsevier
ISBN: 1483102076
Category : Technology & Engineering
Languages : en
Pages : 577
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Book Description
Aerodynamics of Road Vehicles details the aerodynamics of passenger cars, commercial vehicles, sports cars, and race cars; their external flow field; as well as their internal flow field. The book, after giving an introduction to automobile aerodynamics and some fundamentals of fluid mechanics, covers topics such as the performance and aerodynamics of different kinds of vehicles, as well as test techniques for their aerodynamics. The book also covers other concepts related to automobiles such as cooling systems and ventilations for vehicles. The text is recommended for mechanical engineers and phycisists in the automobile industry who would like to understand more about aerodynamics of motor vehicles and its importance on the field of road safety and automobile production.
Author: Naval Surface Weapons Center
Publisher:
ISBN:
Category : Naval research
Languages : en
Pages : 68
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Book Description
