Navier-Stokes predictions of pitch damping for a family of flared projectiles

Abstract

Abstract : A parabolized Navier-Stokes approach has been applied to predict the pitch-damping force and moment coefficients for a family of flared projectiles. This family of flared projectiles, which has been tested in the Army Research Laboratory's (ARL) Aerodynamic Range, consists of a common forebody with various flared afterbodies including straight flares, biconic flares, straked flares, and flares with finlets. The predicted pitch-damping force and moment coefficients are determined from the aerodynamic side force and moment acting on the projectiles due to steady coning motion. The predictions of the flow field about the projectiles undergoing steady coning motion are accomplished using a rotating coordinate frame which rotates at the coning rate of the projectile. The governing equations have been modified to include the centrifugal and Coriolis force terms due to the rotating coordinate frame. The predictions of the pitch-damping moment coefficient are compared with pitch-damping coefficient determined from the inflight motion of the projectile. The predictions of the pitch-damping moment coefficients are in good agreement with the range data.