Reduced-order modeling for linearized aeroelasticity of fixed wings in transonic flight

This paper presents a methodology for the identification of a reduced-order model (ROM) for the perturbation aeroelastic analysis of fixed wings in transonic flight. It is based on a linearized, frequency-domain, boundary-field integral equation for the solution of the unsteady perturbation potential flow about steady-state reference wing configurations. The resulting transfer functions between structural Lagrangean variables and generalized aerodynamic forces are approximated by means of rational expressions, and the aeroelastic ROM is identified by coupling them with the structural operator. With the aeroelastic operator recast in a reduced-order form, transonic flutter boundaries are detected through a classical eigenvalue analysis and the time-domain state-space aeroelastic model is also obtained. Applications of the methodology presented to a widely known aeroelastic test case reveal a remarkable agreement with the measured speed and frequency of flutter.