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Improved Power On Base Drag Methodology For The Aeroprediction Code
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Book Synopsis Improved Power-on, Base Drag Methodology for the Aeroprediction Code by : Frank G. Moore
Download or read book Improved Power-on, Base Drag Methodology for the Aeroprediction Code written by Frank G. Moore and published by . This book was released on 2001-05-01 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved methods for base pressure prediction under base bleed and rocket motor-on conditions have been developed. The base bleed method makes several refinements to the method developed by Danberg at the Army Research Laboratory in Aberdeen, Maryland. The improved rocket motor-on, base pressure prediction improves upon the method developed at the Army Missile Command in Huntsville, Alabama by Brazzel and some of his colleagues. The major refinement to the base bleed method of Danberg was to estimate the power-off value of base pressure empirically based on an extensive data base, as opposed to using computational fluid dynamics codes to predict this term. The major modifications to the power-on base pressure prediction method of Brazzel was to extend its range of applicability to high values of thrust coefficient, to Mach numbers less than 1.5, and to different afterbody shapes. In comparing the improved methods for power-on base drag prediction to experiment, it was seen that both methods gave reasonable agreement to most experimental data bases. However, more validation is needed, particularly for the combined effects of angle of attack, fins, and power-on conditions.
Book Synopsis Improved Power-on, Base Drag Methodology for the Aeroprediction Code by : Frankie Gale Moore
Download or read book Improved Power-on, Base Drag Methodology for the Aeroprediction Code written by Frankie Gale Moore and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Improved methods for base pressure prediction under base bleed and rocket motor-on conditions have been developed. The base bleed method makes several refinements to the method developed by Danberg at the Army Research Laboratory in Aberdeen, Maryland. The improved rocket motor-on, base pressure prediction improves upon the method developed at the Army Missile Command in Huntsville, Alabama by Brazzel and some of his colleagues. The major refinement to the base bleed method of Danberg was to estimate the power-off value of base pressure empirically based on an extensive data base, as opposed to using computational fluid dynamics codes to predict this term. The major modifications to the power-on base pressure prediction method of Brazzel was to extend its range of applicability to high values of thrust coefficient, to Mach numbers less than 1.5, and to different afterbody shapes. In comparing the improved methods for power-on base drag prediction to experiment, it was seen that both methods gave reasonable agreement to most experimental data bases. However, more validation is needed, particularly for the combined effects of angle of attack, fins, and power-on conditions.
Book Synopsis Improved Aeroprediction Code by : Frankie Gale Moore
Download or read book Improved Aeroprediction Code written by Frankie Gale Moore and published by . This book was released on 1993 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and improved version of the Naval Surface Warfare Center, Dahlgren Division aeroprediction code (AP93) has been developed. The new code contains new technology that allows planar aerodynamics of axisymmetric solid rocket-type weapons to be computed with engineering accurately over the entire Mach number range and for angles of attack to 30 deg. New technology developed and included in the AP93 includes; A new engineering method to compute aeroheating information at a high Mach number; Extension of the second-order shock-expansion theory to include real-gas effects, including several new pressure prediction techniques; An improved body-alone nonlinear normal-force method; New methods for computing nonlinear aerodynamics of wing alone, wing body, and body wing due to angle of attack, and wing body due to control deflection; and a new base-dmg database and improved empirical base-drag estimation technique. ... Aeroprediction code (AP93), Planar aerodynamics, High mach number.
Book Synopsis The 2002 Version of the Aeroprediction Code by : Frankie Gale Moore
Download or read book The 2002 Version of the Aeroprediction Code written by Frankie Gale Moore and published by . This book was released on 2002 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Improved Aeroprediction Code: Part I-summary of New Methods and Comparison with Experiment by : Frank G. Moore
Download or read book Improved Aeroprediction Code: Part I-summary of New Methods and Comparison with Experiment written by Frank G. Moore and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: New and improved version of the Naval Surface Warfare Center, Dahlgren Division aeroprediction code (AP93) has been developed. The new code contains new technology that allows planar aerodynamics of axisymmetric solid rocket-type weapons to be computed with engineering accurately over the entire Mach number range and for angles of attack to 30 deg. New technology developed and included in the AP93 includes; A new engineering method to compute aeroheating information at a high Mach number; Extension of the second-order shock-expansion theory to include real-gas effects, including several new pressure prediction techniques; An improved body-alone nonlinear normal-force method; New methods for computing nonlinear aerodynamics of wing alone, wing body, and body wing due to angle of attack, and wing body due to control deflection; and a new base-dmg database and improved empirical base-drag estimation technique. ... Aeroprediction code (AP93), Planar aerodynamics, High mach number.
Book Synopsis The 2002 Version of the Aeroprediction Code. Part 1. Summary of New Theoretical Methodology by : Frank G. Moore
Download or read book The 2002 Version of the Aeroprediction Code. Part 1. Summary of New Theoretical Methodology written by Frank G. Moore and published by . This book was released on 2002-03-01 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The 2002 Version of the Veroprediction Code by : Frank G. Moore
Download or read book The 2002 Version of the Veroprediction Code written by Frank G. Moore and published by . This book was released on 2002 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: "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. ."--DTIC.
Book Synopsis The 2009 Version of the Aeroprediction Code: The AP09 by :
Download or read book The 2009 Version of the Aeroprediction Code: The AP09 written by and published by . This book was released on 2008 with total page 135 pages. Available in PDF, EPUB and Kindle. Book excerpt: The AP05 code was evaluated when applied to configurations with boattails. Results of the evaluation indicated the AP05 predictions for normal force, center of pressure, pitch and roll damping moments needed improvement. As a result new and improved methods were developed and incorporated into the AP05 to be released as the AP09. Improvements include body alone lift characteristics for Mach numbers less than 2, low angle of attack improvements for roll and pitch damping for configurations with long boattails, incorporation of an improved boundary layer displacement model and refinement of several other existing methods. In addition, new methods were developed to predict nonlinear roll and pitch damping. Comparing the new and improved methods to existing experimental data indicated significant improvements in roll and pitch damping, normal force and center of pressure predictions compared to the AP05. However, validation of the AP09 code was not as complete as desired due to limited generic nonlinear roll and pitch damping data. Also, most of the available nonlinear dynamic derivative data has larger than desired accuracy boundaries due to model sting and wind tunnel wall interference issues. Weapons affected most by the new AP09 methodology are mortars, low drag bombs and projectiles in that order. However, the nonlinear dynamic derivative predictions affect all weapons. The AP09 is thus the most accurate and robust of the Aeroprediction Codes to date.
Book Synopsis Influence of Base Modifications on In-flight Base Drag in the Presence of Jet Exhaust for Mach Numbers from 0.7 to 1.5 by : Sheryll Goecke Powers
Download or read book Influence of Base Modifications on In-flight Base Drag in the Presence of Jet Exhaust for Mach Numbers from 0.7 to 1.5 written by Sheryll Goecke Powers and published by . This book was released on 1988 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Refinements in the Aeroprediction Code Based on Recent Wind Tunnel Data by : Frankie Gale Moore
Download or read book Refinements in the Aeroprediction Code Based on Recent Wind Tunnel Data written by Frankie Gale Moore and published by . This book was released on 1999-12-01 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 1998 (AP98) and prior versions of the aeroprediction code are based primarily on slender body and perturbation theories at low angle of attack and empirical constants that represent the nonlinear aerodynamics as a function of angle of attack, Mach number, aspect and taper ratio, and other missile geometric parameters. The primary data base upon which these empirical nonlinear constants were derived was based on the NASA/Tri-Service component data base taken in the 1970s. This data base was limited in body radius to wing semispan plus body radius ratios (r/s) of 0.5. A more recent data base taken by NASA and the former McDonnell Douglas Corporation, investigated other values of the parameter r/s of 0.25, 0.33 and 0.5. As a result of this new data base, the empirical constants in the AP98 were fine-tuned. This fine-tuning has shown the average normal force coefficient errors to be reduced by anywhere from 10 percent to over 40 percent on various missile configurations. The largest reductions in error were for configurations where the AP98 average accuracy was the worst. These new improved empirical constants will be a part of the next planned release of the aeroprediction code in 2002 (AP02). The AP98 average error on normal force coefficient of +/- 10 percent will therefore be somewhat better for the AP02.
Book Synopsis A Coupled Wake-integral/vorticity Confinement Technique for the Prediction of Drag Force by : Troy Snyder
Download or read book A Coupled Wake-integral/vorticity Confinement Technique for the Prediction of Drag Force written by Troy Snyder and published by . This book was released on 2012 with total page 155 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work couples the two enabling technologies of wake-integral drag prediction and Vorticity Confinement (VC) for the improved prediction of drag from an Euler CFD simulation. Induced drag computations of a thin wing are shown to be more accurate than the more common method of surface pressure integration when compared to Prandtl lifting-line theory. Furthermore, the Vorticity Confinement method is shown to improve trailing vortex preservation and counteract the shift from induced to entropy drag as the distance with which the vortex convects downstream of the wing increases. The desired application of this work is drag prediction, most notably induced drag, for aerodynamic design. High-fidelity Euler CFD simulations are desirable as they provide the most complete inviscid flowfield solution. However, accurate induced drag prediction via the surface integration of pressure is generally intractable barring a sufficiently refined surface grid and resultant increase in computational load. Furthermore, the alternative wake-integral technique for drag prediction suffers from numerical dissipation. VC is shown to control the numerical dissipation with very modest computational overhead. VC is implemented in both a two-dimensional finite-volume Euler code written by the author as well as the commercial cfd code ANSYS FLUENT. The two-dimensional research code is used to test specific formulations of the VC body force terms and illustrate the computational efficiency of the method compared to a 'brute force' reduction in spatial step size. For a three-dimensional wing simulation, AN-SYS FLUENT is employed with the VC body force terms added to the solver with user-defined functions (UDFs).
Book Synopsis The 1998 Version of the NSWC Aeroprediction Code by : Frank G. Moore
Download or read book The 1998 Version of the NSWC Aeroprediction Code written by Frank G. Moore and published by . This book was released on 1998-04-01 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis The 1998 Version of the NSWC Aeroprediction Code: Part I-Summary of New Theoretical Methodology by :
Download or read book The 1998 Version of the NSWC Aeroprediction Code: Part I-Summary of New Theoretical Methodology written by and published by . This book was released on 1998 with total page 129 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Book Synopsis Improved Wave Drag Predictions Using Modified Linear Theory by : R. T. Stancil
Download or read book Improved Wave Drag Predictions Using Modified Linear Theory written by R. T. Stancil and published by . This book was released on 1982 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt: The wave drag prediction method is based on a modified supersonic linear theory computer technique. The modified linear theory differs from ordinary linear theory in that it uses the exact, boundary condition, it uses th exact pressure coefficient equation, and it uses characteristic tracing to determine regions of influence. The theoretical and numerical techniques are described in detail. A computer user's manual is included which provides a detailed description of the inputs and outputs of the computer routine, including recommended guidelines for preparing the geometric input. Comparisons between predictions of drag or pressures using the modified linear theory are made for five cases with wind tunnel data or other theories. These comparisons verify the improved accuracy of the modified linear theory relative to ordinary linear theory, particularly for high Mach numbers and high surface slopes.
Book Synopsis Improved Aeroprediction Code by : Frankie Gale Moore
Download or read book Improved Aeroprediction Code written by Frankie Gale Moore and published by . This book was released on 1993 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: New and improved version of the Naval Surface Warfare Center, Dahlgren Division aeroprediction code (AP93) has been developed. The new code contains new technology that allows planar aerodynamics of axisymmetric solid rocket-type weapons to be computed with engineering accurately over the entire Mach number range and for angles of attack to 30 deg. New technology developed and included in the AP93 includes; A new engineering method to compute aeroheating information at a high Mach number; Extension of the second-order shock-expansion theory to include real-gas effects, including several new pressure prediction techniques; An improved body-alone nonlinear normal-force method; New methods for computing nonlinear aerodynamics of wing alone, wing body, and body wing due to angle of attack, and wing body due to control deflection; and a new base-dmg database and improved empirical base-drag estimation technique. ... Aeroprediction code (AP93), Planar aerodynamics, High mach number.
Book Synopsis Nonlinear Structural Load Distribution Methodology for the Aeroprediction Code by : Roy M. McInville
Download or read book Nonlinear Structural Load Distribution Methodology for the Aeroprediction Code written by Roy M. McInville and published by . This book was released on 1996-09-01 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: New methodology has been added to the NSWCDD Aeroprediction code to permit the distribution of the local linear and nonlinear aerodynamic loads along the body length and over the wing and tail lifting surfaces. The new techniques extend to both the PHI = 0 deg and PHI = 45 deg roll positions and to both windward and leeward lifting surfaces in the 45 deg orientation. The local loads are integrated to get the distribution of the shear and bending moments for use in structural analysis and design. Navier-Stokes CFD computations for the Seasparrow missile were used in the development of these extensions to the code and in validating their effectiveness. In general, good agreement with the CFD results is obtained.
Book Synopsis Recent Advances in Aerospace Engineering by : Sanjay Singh
Download or read book Recent Advances in Aerospace Engineering written by Sanjay Singh and published by Springer Nature. This book was released on with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt:
