The effects of forebody strakes on asymmetric vortices on a vertically launched missile

Abstract

Wind tunnel tests were conducted on a vertically launched surface-to- air missile model to investigate the effects of forebody stakes on the side forces and yawing moments induced by nose-generated asymmetric vortices at high angles of attack. The effects of body configuration and a turbulent flowfield on the induced side forces and yawing moments were also examined. Test angles of attack ranged from 0 to 90 at Reynolds number of 150,000 based on the model diameter, and at a March number of 0.11. Three forebody configurations, two body configurations and two flowfield conditions were investigated. The flowfield with a turbulence length scale on the order of the vortex scale was found to have no significant influence on the induced side forces and yawing moments. The change of body configuration had no strong effects on the side forces and yawing moments either. The '4 STRAKES' forebody demonstrated dramatic results in the yawing moment alleviation; the ranges of angle of attack in the induced side forces and yawing moments were also decreased by this modification. The '8' STRAKES forebody gave no significant improvement in the induced side force and yawing moment reduction.