An Improved Semiempirical Method For Calculating Aerodynamics Of Missiles With Noncircular Bodies

An improved method has been developed to compute aerodynamics of noncircular cross section shapes. The improved method is based on extending current state of the art methods for computing aerodynamics of noncircular wing- body shapes based on circular wing-body methods. Specific additions to the state of the art methods presently in use include extensions to a broader class of cross section bodies and to a higher angle of attack (AOA); extensions to allow improved accuracy at low cross flow Mach number and to allow body cross section shape to impact the critical cross flow Reynolds number; and a method to treat wing-body interference factor corrections as a function of body geometry, Mach number, and AOA. The new methods were applied to a broad class of noncircular body alone and wing body configurations for which wind tunnel data were available. In general, results for normal force, axial force and center of pressure were quite good over the Mach number and AOA range where data was available. This included Mach numbers as low as 0.3 and as high as 14 and AOAs to 60 degrees.

An improved method has been developed to compute aerodynamics of noncircular cross section shapes. The improved method is based on extending current state of the art methods for computing aerodynamics of noncircular wing-body shapes based on circular wing-body methods. Specific additions to the state of the art methods presently in use include extensions to a broader class of cross section bodies and to a higher angle of attack (AOA); extensions to allow improved accuracy at low cross flow Mach number and to allow body cross section shape to impact the critical cross flow Reynolds number; and a method to treat wing-body interference factor corrections as a function of body geometry, Mach number, and AOA. The new methods were applied to a broad class of noncircular body alone and wing body configurations for which wind tunnel data were available. In general, results for normal force, axial force and center of pressure were quite good over the Mach number and AOA range where data was available. This included Mach numbers as low as 0.3 and as high as 14 and AOAs to 60 degrees.

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.

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.

This report discusses the pros and cons of numerical, semiempirical and empirical aeroprediction codes and lists many state-of-the-art codes in use today. It then summarizes many of the more popular approximate analytical methods used in State-of-the-Art (SOTA) semiempirical aeroprediction codes. It also summarizes some recent new nonlinear semiempirical methods that allow more accurate calculation of static aerodynamics on complete missile configurations to higher angles of attack. Results of static aerodynamic calculations on complete missile configurations compared to wind tunnel data are shown for several configurations at various flight conditions. Calculations show the new nonlinear methods being far superior to some of the former linear technology when used at angles of attack greater than about 15 degrees. Aeroprediction codes, Nonlinear semiempirical methods, State-of-the-Art (SOTA) semiempirical aeroprediction codes, Static aerodynamic calculations.

The International Conference of Computational Methods in Sciences and Engineering (ICCMSE) is unique in its kind. It regroups original contributions from all fields of the traditional Sciences, Mathematics, Physics, Chemistry, Biology, Medicine and all branches of Engineering. The aim of the conference is to bring together computational scientists from several disciplines in order to share methods and ideas. More than 370 extended abstracts have been submitted for consideration for presentation in ICCMSE 2004. From these, 289 extended abstracts have been selected after international peer review by at least two independent reviewers.