Author: Earl A. Price (Jr.)
Publisher:
ISBN:
Category : Drag (Aerodynamics)
Languages : en
Pages : 182
Book Description
A Parametric Investigation of the Annular Jet Concept for Obtaining Afterbody Drag Data at Transonic Mach Numbers
A Parametric Investigation of the Annular Jet Concept for Obtaining Afterbody Drag Data at Transonic Mach Numbers
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A parametric experimental program was conducted at free-stream Mach numbers of 0.6, 0.9, and 1.2 to investigate the plume simulation characteristics of annular jets. Plume simulation evaluation was based upon comparisons of afterbody pressure drag from integration of afterbody pressure measurements. Data were obtained on a 15-deg boattail afterbody attached to a strut-supported cylindrical centerbody. Geometric variables covered a range of sting-to-nozzle exit diameter ratios from 0 to 0.95 and nozzle area ratios from 1.0 to 1.5. High pressure air at ambient temperature was utilized for the exhaust gas. The results indicate that matching of the exhaust plume maximum diameter provides a reasonable afterbody drag correlation, accounting for effects of annular jet, nozzle exit-to-throat area ratio, and nozzle pressure ratio for conditions where drag follows the classical trend indicative of a plume shape dependence. Plume diameter correlation was not successful, for the pressure ratios of this investigation, for annular jet configurations having sting-to-nozzle exit diameter ratios of 0.95 at all Mach numbers and 0.866 at Mach number 1.2. There were no significant differences in the trends with angle of attack between the annular and conventional jet configurations over the angle-of-attack range from -2 to 6 deg. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A parametric experimental program was conducted at free-stream Mach numbers of 0.6, 0.9, and 1.2 to investigate the plume simulation characteristics of annular jets. Plume simulation evaluation was based upon comparisons of afterbody pressure drag from integration of afterbody pressure measurements. Data were obtained on a 15-deg boattail afterbody attached to a strut-supported cylindrical centerbody. Geometric variables covered a range of sting-to-nozzle exit diameter ratios from 0 to 0.95 and nozzle area ratios from 1.0 to 1.5. High pressure air at ambient temperature was utilized for the exhaust gas. The results indicate that matching of the exhaust plume maximum diameter provides a reasonable afterbody drag correlation, accounting for effects of annular jet, nozzle exit-to-throat area ratio, and nozzle pressure ratio for conditions where drag follows the classical trend indicative of a plume shape dependence. Plume diameter correlation was not successful, for the pressure ratios of this investigation, for annular jet configurations having sting-to-nozzle exit diameter ratios of 0.95 at all Mach numbers and 0.866 at Mach number 1.2. There were no significant differences in the trends with angle of attack between the annular and conventional jet configurations over the angle-of-attack range from -2 to 6 deg. (Author).
A Parametric Investigation of the Annular Jet Concept for Obtaining Afterbody Drag Data at Transonic Mach Numbers
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A parametric experimental program was conducted at free-stream Mach numbers of 0.6, 0.9, and 1.2 to investigate the plume simulation characteristics of annular jets. Plume simulation evaluation was based upon comparisons of afterbody pressure drag from integration of afterbody pressure measurements. Data were obtained on a 15-deg boattail afterbody attached to a strut-supported cylindrical centerbody. Geometric variables covered a range of sting-to-nozzle exit diameter ratios from 0 to 0.95 and nozzle area ratios from 1.0 to 1.5. High pressure air at ambient temperature was utilized for the exhaust gas. The results indicate that matching of the exhaust plume maximum diameter provides a reasonable afterbody drag correlation, accounting for effects of annular jet, nozzle exit-to-throat area ratio, and nozzle pressure ratio for conditions where drag follows the classical trend indicative of a plume shape dependence. Plume diameter correlation was not successful, for the pressure ratios of this investigation, for annular jet configurations having sting-to-nozzle exit diameter ratios of 0.95 at all Mach numbers and 0.866 at Mach number 1.2. There were no significant differences in the trends with angle of attack between the annular and conventional jet configurations over the angle-of-attack range from -2 to 6 deg. (Author).
Publisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
A parametric experimental program was conducted at free-stream Mach numbers of 0.6, 0.9, and 1.2 to investigate the plume simulation characteristics of annular jets. Plume simulation evaluation was based upon comparisons of afterbody pressure drag from integration of afterbody pressure measurements. Data were obtained on a 15-deg boattail afterbody attached to a strut-supported cylindrical centerbody. Geometric variables covered a range of sting-to-nozzle exit diameter ratios from 0 to 0.95 and nozzle area ratios from 1.0 to 1.5. High pressure air at ambient temperature was utilized for the exhaust gas. The results indicate that matching of the exhaust plume maximum diameter provides a reasonable afterbody drag correlation, accounting for effects of annular jet, nozzle exit-to-throat area ratio, and nozzle pressure ratio for conditions where drag follows the classical trend indicative of a plume shape dependence. Plume diameter correlation was not successful, for the pressure ratios of this investigation, for annular jet configurations having sting-to-nozzle exit diameter ratios of 0.95 at all Mach numbers and 0.866 at Mach number 1.2. There were no significant differences in the trends with angle of attack between the annular and conventional jet configurations over the angle-of-attack range from -2 to 6 deg. (Author).
An Investigation of F-16 Nozzle-afterbody Forces at Transonic Mach Numbers with Emphasis on Support System Interference
Author: Earl A. Price (Jr.)
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 416
Book Description
A comprehensive experimental program was conducted to provide nozzle-afterbody data with a minimum interference support system on a 1/9-scale F-16 model and to determine the interference induced on the afterbody-nozzle region by a sting, a wingtip, and a strut model support system. The investigation was conducted over the Mach number range from 0.6 to 1.5 and at angles of attack from 0 to 9 deg. Interference was evaluated by comparison of nozzle-afterboy axial and normal forces obtained from integrating pressure data. The results include parametric studies of the efects of various components of the wingtip support system (i.e., the support blade axial position, wingtip boom diameter, boom spacing, and boom-tip axial location). High-pressure air at ambient temperature was utilized for exhaust plume simulation. The results indicate that a sting support passing through the nozzle with the jet effects simulated by an annular jet appears to offer a minimum interference support system for the type of nozzle-afterbody test described in this report.
Publisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 416
Book Description
A comprehensive experimental program was conducted to provide nozzle-afterbody data with a minimum interference support system on a 1/9-scale F-16 model and to determine the interference induced on the afterbody-nozzle region by a sting, a wingtip, and a strut model support system. The investigation was conducted over the Mach number range from 0.6 to 1.5 and at angles of attack from 0 to 9 deg. Interference was evaluated by comparison of nozzle-afterboy axial and normal forces obtained from integrating pressure data. The results include parametric studies of the efects of various components of the wingtip support system (i.e., the support blade axial position, wingtip boom diameter, boom spacing, and boom-tip axial location). High-pressure air at ambient temperature was utilized for exhaust plume simulation. The results indicate that a sting support passing through the nozzle with the jet effects simulated by an annular jet appears to offer a minimum interference support system for the type of nozzle-afterbody test described in this report.
A Method for Estimating Jet Entrainment Effects on Nozzle-afterbody Drag
Author: R. C. Bauer
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 30
Book Description
A highly simplified analysis was used to derive an expression for estimating the induced afterbody drag caused by the turbulent jet-mixing process. The approach estimates the induced velocity produced by the jet-mixing process and uses small perturbation concepts to estimate the resulting pressure change on the afterbody surface from which the induced afterbody drag coefficient is obtained. The theoretical induced afterbody drag (entrainment drag) is combined with the maximum jet plume diameter blockage condition to form a correlation method that accounts for the effect of jet area ratio, exit angle, total temperature, molecular weight and ratio of specific heats for a given external stream Mach number, Reynolds number, and afterbody geometry. For verification, the correlation method was used to predict the drag of an H2 and C2H4 jet from the measured drag of an N2 jet and to predict the drag of a hot jet from the measured drag of a cold jet for both the 15- and 25-deg AGARD afterbody configurations in the Mach number range from 0.6 to 1.5. The average accuracy of the correlation method is better than 10% for both afterbody configurations and is 40 to 50 % more accurate than a correlation method based only on the blockage parameter. A brief numerical study indicates that the major parameter which correlates the jet entrainment effect is the product of the jet gas constant and total temperature. (Author).
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 30
Book Description
A highly simplified analysis was used to derive an expression for estimating the induced afterbody drag caused by the turbulent jet-mixing process. The approach estimates the induced velocity produced by the jet-mixing process and uses small perturbation concepts to estimate the resulting pressure change on the afterbody surface from which the induced afterbody drag coefficient is obtained. The theoretical induced afterbody drag (entrainment drag) is combined with the maximum jet plume diameter blockage condition to form a correlation method that accounts for the effect of jet area ratio, exit angle, total temperature, molecular weight and ratio of specific heats for a given external stream Mach number, Reynolds number, and afterbody geometry. For verification, the correlation method was used to predict the drag of an H2 and C2H4 jet from the measured drag of an N2 jet and to predict the drag of a hot jet from the measured drag of a cold jet for both the 15- and 25-deg AGARD afterbody configurations in the Mach number range from 0.6 to 1.5. The average accuracy of the correlation method is better than 10% for both afterbody configurations and is 40 to 50 % more accurate than a correlation method based only on the blockage parameter. A brief numerical study indicates that the major parameter which correlates the jet entrainment effect is the product of the jet gas constant and total temperature. (Author).
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 782
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 782
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
NASA Technical Memorandum
Government Reports Announcements & Index
NASA SP.
Aeronautical Engineering
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 648
Book Description
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 648
Book Description
A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).