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Army Research Laboratory, USA 2 Abstract A method to efficiently generate a complete aerodynamic description for projectile flight dynamic modeling is described. At the core of the method is an unsteady, time accurate computational fluid dynamics simulation that is tightly coupled to a rigid body dynamics simulation. A set of n short time snippets of simulated projectile motion at m 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.

This means that aerodynamic forces, aerodynamic moments, position of the mass center, body orientation, translational velocity, and angular velocity of the projectile are all known at the same time instant. With time synchronized air load and state vector information, the aerodynamic coefficients can be estimated with a simple fitting procedure. This paper creates a method to efficiently generate a complete aerodynamic model for a projectile in atmospheric flight using n short time histories at m different Mach numbers with an industry standard time accurate CFD/RBD simulation.

The same results are obtained (with millimeter accuracy) from the analytical and the numerical method. The analytical deflections are calculated using eq. (26) yielding the same values as the fast calculation programme. 2 Example 2 The same projectile and data are used as in example 1 with the exception of the gun elevation angle φ0 = 46° and the latitude ψ = 45°. Table 2 shows the results. The values in brackets are analytically calculated deflections which deviate from the corresponding numerical values.