Investigation of pitching frequency impact on stability criteria for supersonic fin stabilized missile

Abstract

The stability criteria of any fin-stabilized flying object are a decisive metric in evaluating its overall performance and results in mission success. Flight stability depends on many parameters such as body configuration, the center of gravity location, atmospheric conditions, and flight manoeuvres. These manoeuvres are needed for better target interception especially for moving targets located at short ranges, resulting in high frequencies either in pitch or yaw directions. This study examines the impact of body pitch frequency on the stability of a supersonic fin-stabilized object. Time-dependent numerical simulations are implemented to model the unsteady flow field induced by a simple harmonic motion in the case study missile. The missile’s tail section dominates the lift force generated compared to the forebody, resulting in a downstream shift of the missile’s center of pressure and, consequently, an increase in the static stability margin as the pitching frequency increases. However, pitch-damp aerodynamic derivatives remain unchanged at various pitching frequencies, indicating frequency independence. The validity of the results is confirmed compared with wind tunnel data.