The 1998 Version of the NSWC Aeroprediction Code: Part I-Summary of New Theoretical Methodology PDF Download
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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 129
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Book Description
The NSWC Aero prediction code has been extended to the roll position of 45 deg (fins in 'x' or cross roll orientation) in addition to the roll position of 0 deg (fins in '+' or plus roll orientation). It has also been extended to compute aerodynamics of nonaxisymmetric bodies based on an equivalent axisymmetric body. In addition, the nonlinear aerodynamic loads have been distributed over the body and lifting surfaces to provide a more useful tool for preliminary structural analysis. Finally, new technology was developed to improve the prediction of axial force at angle of attack (AOA). These new technologies have been integrated into the AP95 and will be transitioned to legitimate users as the AP98. To make the AP98 more user friendly, an upgraded pre- and post-processing, personal computer interface was also developed. Comparisons of the new theory have been made to both experimental data and the AP95. Comparisons of theory and experiment show the AP98 to be at least as good as the AP95 and, in general, maybe slightly better. In general, average accuracy levels of aerodynamics are +/- 10 percent on axial and normal force and +/- 4 percent of body length on center of pressure. For nonaxisymmetric body cases, accuracy can be slightly higher than these numbers, although not enough cases have been considered to make a definitive assessment. While these accuracy levels are encouraging for a semiempirical code, they could be improved upon by use of computational fluid dynamics codes or additional experimental data or both to reduce errors due to limited data bases.
Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 129
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Book Description
The NSWC Aero prediction code has been extended to the roll position of 45 deg (fins in 'x' or cross roll orientation) in addition to the roll position of 0 deg (fins in '+' or plus roll orientation). It has also been extended to compute aerodynamics of nonaxisymmetric bodies based on an equivalent axisymmetric body. In addition, the nonlinear aerodynamic loads have been distributed over the body and lifting surfaces to provide a more useful tool for preliminary structural analysis. Finally, new technology was developed to improve the prediction of axial force at angle of attack (AOA). These new technologies have been integrated into the AP95 and will be transitioned to legitimate users as the AP98. To make the AP98 more user friendly, an upgraded pre- and post-processing, personal computer interface was also developed. Comparisons of the new theory have been made to both experimental data and the AP95. Comparisons of theory and experiment show the AP98 to be at least as good as the AP95 and, in general, maybe slightly better. In general, average accuracy levels of aerodynamics are +/- 10 percent on axial and normal force and +/- 4 percent of body length on center of pressure. For nonaxisymmetric body cases, accuracy can be slightly higher than these numbers, although not enough cases have been considered to make a definitive assessment. While these accuracy levels are encouraging for a semiempirical code, they could be improved upon by use of computational fluid dynamics codes or additional experimental data or both to reduce errors due to limited data bases.
Author: Frank G. Moore
Publisher:
ISBN: 9781423562726
Category :
Languages : en
Pages : 129
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Book Description
The NSWC Aero prediction code has been extended to the roll position of 45 deg (fins in 'x' or cross roll orientation) in addition to the roll position of 0 deg (fins in '+' or plus roll orientation). It has also been extended to compute aerodynamics of nonaxisymmetric bodies based on an equivalent axisymmetric body. In addition, the nonlinear aerodynamic loads have been distributed over the body and lifting surfaces to provide a more useful tool for preliminary structural analysis. Finally, new technology was developed to improve the prediction of axial force at angle of attack (AOA). These new technologies have been integrated into the AP95 and will be transitioned to legitimate users as the AP98. To make the AP98 more user friendly, an upgraded pre- and post-processing, personal computer interface was also developed. Comparisons of the new theory have been made to both experimental data and the AP95. Comparisons of theory and experiment show the AP98 to be at least as good as the AP95 and, in general, maybe slightly better. In general, average accuracy levels of aerodynamics are +/- 10 percent on axial and normal force and +/- 4 percent of body length on center of pressure. For nonaxisymmetric body cases, accuracy can be slightly higher than these numbers, although not enough cases have been considered to make a definitive assessment. While these accuracy levels are encouraging for a semiempirical code, they could be improved upon by use of computational fluid dynamics codes or additional experimental data or both to reduce errors due to limited data bases.
Author: Frankie Gale Moore
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 232
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Book Description
A new version of the aeroprediction code (APC), the AP02, has been developed to address the requirements arising from advanced weapon concepts. The AP02 was formed by adding significant new technology and several productivity improvements to the previous version of the APC, the AP98. New technology added included 6 and 8 fin aerodynamics, improved nonlinear aerodynamics, improved pitch damping predictions, improved power-on base drag estimates, base-bleed effect on base drag estimation, improved axial force of nonaxisymmetric bodies and trailing-edge flap capability. Other improvements and productivity enhancements include an aerodynamic smoother, ballistic and three degree-of-freedom simulation modules as well as refinements for the pre- and post-processor for inputs and outputs of the AP02. Comparison of the predicted aerodynamics of the AP02 to AP98 and experimental data showed the AP02 to be slightly better than the AP98 in most cases that both codes would handle. However, due to the additional new technology incorporated into the AP02, many new options are available in the AP02 that are not available in the AP98. Therefore, the AP02 is more robust and, on average, is slightly more accurate than the AP98 in predicting aerodynamics of weapons.
Author: Frankie Gale Moore
Publisher:
ISBN:
Category : Angle of attack (Aerodynamics).
Languages : en
Pages : 114
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Book Description
The NSWC Aeroprediction Code has been extended to angles of attack (AOA) greater than 30 deg. To accomplish this, several data bases were used to approximate the nonlinearities in individual missile component aerodynamics. Theoretical aerodynamic methods are used at small AOA. The new semiempirical model was applied to several configurations and the empirical constants adjusted to eliminate some of the errors associated with wind tunnel measurements of individual missile component loads. The new version of the code (AP95) was then pplied to several other missile configurations and estimates compared to data and other aerodynamic code calculations. Comparisons were made for Mach numbers 0.1 to 10.0 and AOA of 0 to 90 deg (not all data were available on any single configuration). In general, average accuracy levels of ±10 percent could be obrained for axial and normal force coefficeint and ±4 percent of body length for center of pressure, using the AP95. An exception to this was at AOA above 30 deg and at high supersonic Mach numbers, where nonlinearities caused by internal shock interactions were not accounted for. While these accuracy levels are very encouraging for a semiempirical code, improvements in the AP95 methodology could be made by additional missile-component wind-tunnel data at high AOA.
Author: Naval Surface Warfare Center (U.S.). Dahlgren Division
Publisher:
ISBN:
Category :
Languages : en
Pages : 180
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Book Description
Author: Thomas C. Hymer
Publisher:
ISBN:
Category : Aerofoils
Languages : en
Pages : 0
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Book Description
This report describes interactive, user friendly, pre-processing and post-processing personal computer (P.C.) modules designed to operate with the latest version of the Naval Surface Warfare Center (NSWC) Aeroprediction Code (AP98). As part of the preprocessing input module, geometry inputs are automated by giving the user many options. By using this new software, a set of aerodynamic coefficients can be obtained on most weapon configurations in less than 15 minutes from time of initial setup to computer outputs, compared to 2-4 hours for the AP98 computer mainframe version, While the computer cost savings are modest (the AP98 executes on a large computer in less than a second), the manpower savings and productivity enhancements can be significant. Various plots of the aerodynamic coefficients are available to the user and are plotted automatically by the post-processing module. Data output is also made available to the user in the form of standard Aeroprediction output files as well as tabulated data. The User's Guide is designed to aid users of the AP98 by correlating AP98 P.C. Interface Data Inputs and the corresponding source code variable names.
Author: Frankie Gale Moore
Publisher: AIAA (American Institute of Aeronautics & Astronautics)
ISBN:
Category : History
Languages : en
Pages : 488
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Book Description
Moore brings 30 years of experience in weapons development to help bridge the gap between the academic textbook and practical application. The book reviews all approaches to calculate aerodynamics, allowing engineers to see the pros and cons of each approach, setting the stage for a semiempirical approach. It contains many approximate aerodynamic methods, bringing together in a single text both linearized and nonlinear aerodynamic methods. Practicing engineers will value the books emphasis on understanding the physics involved, understanding the assumptions made to get to the approximate approaches, and showing final equations used in the solution process.
Author: F. G. Moore
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 826
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Book Description
Author: D. D. Liu
Publisher:
ISBN:
Category : Aeroelasticity
Languages : en
Pages : 120
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Book Description
The adaptation of ZONA unified hypersonic/supersonic method ZONA7U and its integration/development into a ZONA aerothermoelastic software system for transatmospheric vehicle (TAV)/thermal protection system (TPS) design/analysis was proven a successful tool through feasibility study with cases of a CKEM body, blunt cones, and a modeled X-34 wing body. Preceding the feasibility study, substantial effort was directed toward further development of a new code, ZSTREAM, and using it and ZABRO to replace the outdated modules in SHVD, thus to couple them with SHABP for aerothermoelastic applications. In the feasibility study, the cases are well validated with FD solutions. Next, computed heat rates by applying ZONA aerothermoelastic software to X-34 through two assigned hypersonic trajectories were shown and found to agree with those using MINIVER. A potential TPS design procedure was established using the obtained heat rates as an input to MINIVER, resulting in a minimum weight TPS per hot-wall consideration. With FEM/TRIM modules, ASTROS* yields the trim solution and stress distribution for a flexible X-34 at a typical trajectory joint, demonstrating the multifunctionality in MDO for the aerothermoelastic software.
