Effect of Fins on the Mean Base Flow of a Generic Supersonic Projectile

Le résumé fourni par la source

Accurately predicting the aerodynamics around slender, finned projectiles is critical to ensuring optimal performance. Much of the research on these configurations has emphasized understanding of the overall forces and moments, as well as forebody aerodynamic features such as vortices formed by the nosecone and fins. Despite its importance in the aerodynamics of slender projectiles, the flow downstream of these vehicles, i.e., the wake or base flow, has primarily been examined without the presence of fins. Since they substantially alter the flow direction for maneuvering purposes, fins can have a profound impact on the base region flow physics. This study focuses on narrowing the gap of knowledge between the base flow of slender bodies with and without fins. To accomplish this, Reynolds-averaged Navier-Stokes (RANS) simulations are conducted on a generic finned projectile, with four high-aspect ratio, cropped-delta fins, at Mach 2.0 across various roll and pitch angles with and without the fins. The results are validated with previous experimental force and moment measurements of the projectile, as well as literature on the wake flow of similar finless configurations. The base flow is characterized through a series of qualitative and quantitative criteria, the former in terms of the shock and vortical structures and the latter with an analysis of the base pressures. The simulations indicate that at zero angle-of-attack, the fin trailing edge introduces new shock/expansion structures that alter the shape and strength of shock/expansion structures in the base region. With pitch and roll, many of the upstream vortical structures, such as fin-tip vortices, further change the wake flow, including the shape and strength of key shock structures, along with resulting effects on base pressure. These results also aid in narrowing the parameter space for future scale-resolving simulations to study the unsteady behavior of slender body wakes.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.