Newtonian-Optimized Aft-Body Flares for High-Mach Drag Reduction

Aft-body flares are used on rockets and reentry vehicles to facilitate achieving stability at high speeds while not suffering the same heating issues that plague fins with thin leading edges. They are mainly employed in vehicles that are designed to reach high altitudes and speeds along a ballistic or quasi-ballistic trajectory. In this study, the lift, drag, and pitching moment characteristics of two flare shapes were analyzed in CFD using Star-CCM+. CFD calculations were made at [Formula: see text] and [Formula: see text] at 40 kft (12.192 km) standard atmosphere conditions at angles of attack ranging from 0 to 10 deg. A conical flare was used as a baseline for comparison against a new flare design. The new design was shaped using a Newtonian aerodynamics-based approach to lower the pressure drag on the aft-body flare. The new design reduced total vehicle drag compared to the conical design across all analyzed Mach numbers, angles of attack, and flare angles. Drag was reduced by up to 10% while minimally impacting vehicle lift and stability.