Drag Reduction for Turbulent Flow over a Projectile: Part I

TLDR: In this article, a numerical study was made to analyze the performance of a secant-ogive-cylinder-boattail projectile in the transonic Mach number regime between 0.91 and 1.20.

Abstract: A numerical study is made to analyze the drag performance of a secant-ogive-cylinder-boattail projectile in the transonic Mach number regime between 0.91 and 1.20. To improve the projectile's performance, two drag reduction methods, boattailing and base bleed, are applied. The effectiveness of each method and the combination of both methods are studied by varying the values of parameters such as boattail angle, bleed quantity, and bleed area. The computed distributions of surface pressure coefficient of the projectile with different boattail angles are in close agreement with experimental data. Computed drag components and the total drag of the projectile are accurate by comparison with experimental data and semiempirical predictions. The optimal boattail angle for total drag reduction is predicted to be at about 5-7 deg. The method of combining boattailing and base bleed can become an effective method for total drag reduction.