A computational fluid dynamics (CFD) approach to predicting high- speed aerodynamic flow fields of interest to the U.S. Army Research Laboratory (ARL) has been carried out The aerodynamic problems of particular interest are: (1) supersonic flow past the aftbody of projectiles with base mass injection, (2) supersonic flow past the M549 projectile, and (3) subsonic, transonic, and supersonic flow past an M864 projectile with base bleed and wake combustion. The commercially available FLUENT (Fluent, Inc. FLUENT. Version 5.1.1, Lebanon, NH, 1999.) CFD code was utilized. The computational effort supports an ongoing ARL- sponsored experimental investigation. Of particular interest in the present investigation is the careful characterization of the various turbulence models employed in the CFD code. Additionally, the ease of use and set-up as well as the computational time will be described. An experimental effort (Dutton, J. C., and A. L. Addy. 'Fluid Dynamic Mechanisms and Interactions Within Separated Flows'. U.S. Army Research Office Research Grant DAAH04-93-G-0226 and the Department of Mechanical and Industrial Engineering, University of illinois, Urbana-Champagne, Urbana, IL, August 1998.) consisting of detailed laser Doppler velocimeter (LDV), particle image velocimeter (PIV), and high-speed wall pressure measurements has been made in axisymmetric and planar subsonic and supersonic flows with embedded separated regions. The present work seeks to predict similar flow fields computationally and to address areas of agreement and disagreement.