Reduced-Frequency Approach for Calculating Dynamic Derivatives

Abstract

A novel method of calculating dynamic stability derivatives using Computational Fluid Dynamics is presented. This method uses a non-linear, reduced-frequency approach to simulate the response to a forced oscillation using a single frequency component at the forcing frequency. This provides an order of magnitude improvement in computational e ciency over similar time-dependent schemes without loss of generality. The reduced-frequency approach is implemented with an automated Cartesian mesh scheme. This combination of Cartesian meshing and reduced-frequency solver enables damping derivatives for arbitrary flight condition and geometric complexity to be e ciently and accurately calculated. The method is validated for 3-D reference missile and aircraft dynamic test configurations through the transonic and high-alpha flight regimes. Comparisons with the results of time-dependent simulations are also included.