Forebody Geometry Effects on the Flowfield of a Blunt-Nose Projectile at High Alpha

摘要

Wind-tunnel experiments are conducted on a projectile at high incidence to examine the effect of nose shapes and a passive strake control device on the side force and yawing moment. The study was also aimed at gaining some insights into the fluid mechanics of blunt-nose bodies of revolution at high angles of attack. Detailed flow visualization and force measurements are obtained on a projectile with a fineness ratio of 4 at a Reynolds number of 0.19 × 10~6 and 42-and 48-deg angles of attack. Off- and on-surface flow visualization records are collected to study the effects of two blunt noses: a hemispherical nose and an elliptical nose with 33% ellipticity. It was found that the elliptical nose results in flow behaviors typical of a blunt nose, whereas the hemispheric nose results in behaviors that are akin to a pointed nose. An explanation for the contrasting behaviors is provided.