Using computational fluid dynamic/rigid body dynamic results to generate aerodynamic models for projectile flight simulation

Abstract

A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modelling is described. At the core of the method is an unsteady, time accurate computational fluid dynamic simulation that is tightly coupled to a rigid projectile flight dynamic simulation. A set of short time snippets of simulated projectile motion at different Mach numbers is computed and employed as baseline data. For each time snippet, aerodynamic forces and moments and the full rigid body state vector of the projectile are known. With time synchronized air loads and state vector information, aerodynamic coefficients can be estimated with a simple fitting procedure. By inspecting the condition number of the fitting matrix, it is straightforward to assess the suitability of the time history data to predict a selected set of aerodynamic coefficients. The technique it is exercised on an exemplar fin-stabilized projectile with good results.