User S Guide For An Interactive Personal Computer Interface For The 1998 Aeroprediction Code Ap98

User's Guide for an Interactive Personal Computer Interface for the 1998 Aeroprediction Code (AP98)

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.

The 2002 Version of the Aeroprediction Code

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.

Refinements in the Aeroprediction Code Based on Recent Wind Tunnel Data