Author(s)

J. Sahu

Abstract

This paper describes a new multidisciplinary computational study undertaken to model the flight trajectories and the free-flight aerodynamics of both a finned projectile at supersonic velocities and a spinning projectile at subsonic speeds with and without aerodynamic flow-control. Actual flight trajectories are computed using an advanced coupled computational fluid dynamics (CFD)/rigid body dynamics (RBD) technique. An advanced time-accurate Navier–Stokes computational technique has been used in CFD to compute the unsteady aerodynamics associated with the free-flight of the finned projectile at supersonic speeds and the spinning projectile at subsonic speeds. Computed positions and orientations of the projectile have been compared with actual data measured from free-flight tests and are found to be generally in good agreement. Predicted aerodynamics forces and moments compare well with the forces and moments used in the six degree freedom fits of the results of the same tests. Unsteady numerical results obtained from the coupled method show the flow field, the aerodynamic forces and moments, and the flight trajectories of the projectile. Keywords: unsteady CFD, projectile aerodynamics, couple CFD/RBD method, flight trajectory. 1 Introduction Understanding the aerodynamics of projectiles, rockets, and missiles is critical to the design of stable configurations and contributes significantly to the overall performance of weapon systems [1-3]. The prediction of aerodynamic coefficients for these weapon systems is essential in assessing the performance of new designs. Numerical simulations have the potential of greatly reducing design costs while providing a detailed understanding of the complex

Keywords

unsteady CFD, projectile aerodynamics, couple CFD/RBD method, flight trajectory.