NONLINEAR REDUCED ORDER MODELS OF UNSTEADY AERODYNAMICS FOR NON-CLASSICAL AILERON BUZZ ANALYSIS

摘要

A reduced order model of the unsteady aerodynamics is developed for the analysis of non-classical aileron buzz. A high-fidelity model of the dynamic system is defined coupling a CFD aerodynamic model based on the Euler equations with the structural dynamics of the rigid aileron. A state-space realization of the aerodynamic reduced-order model is considered and a continous-time system identification based on a genetic algorithm is employed. In order to represent the nonlinearity of the aerodynamics in the transonic regime a polynomial function of the input is added to the linear model structure. From the reduced-order model of the aerodynamics a low-order aeroelastic system is determined, whose dynamic response is compared to that of the CFD-based model.