A Flight Simulator for Agile Fighter Aircraft and Nonlinear Aerodynamics

Physics-based reduced-order models have been developed that can accurately and efficiently simulate key aspects of aircraft flight operations including aerodynamics, aeroelasticity, and control-surface dynamics at subsonic, transonic, and supersonic flight speeds and rapidly changing, nonlinear post-stall conditions. The modeling technology enables flight simulations and virtual flight testing of agile (highly maneuverable) fighter aircraft. Order reduction is effected by transforming from physical space to modal space using the method of proper orthogonal decomposition. Modal models constructed with a relatively small set of data from high-fidelity, computationally intensive CFD simulations (where flow properties are computed in physical space) are capable of accurately predicting the flight dynamics for a wide range of aggressive aircraft maneuvers in simulations that are significantly faster than real time. Model accuracy is demonstrated through comparisons with data from CFD simulations of an open-source fighter aircraft with and without wing stores (modeled after an F-16) and an F-16 aircraft with articulating control surfaces. Model evaluations include both rigid and flexible versions of the aircraft.