Abstract: This paper aims at providing an accurate and efficient method for aeroelastic simulation. System identification is used to get the reduced order models of unsteady aerodynamics. LS(Least Square) method is used to estimate the coefficients of the input-output difference model. The reduced order models (ROM) are then used in place of the unsteady CFD codes for aeroelastic simulation. The efficiency is improved 1-2 orders while still retaining the accuracy of the complete unsteady CFD codes. Two standard aeroelastic computing examples (2D Isogai wing with S type flutter boundary and 3D transonic flutter example-AGARD445.6 wing) are computed. The computed flutter boundaries based on ROM are well compared with those of the directly coupling CFD/CSD method. The identification technology of unsteady aerodynamic loads shows a high efficient and accuracy approach for transonic aeroelastic solving.

Key words: aeroelasticity, flutter, unsteady aerodynamics identification, Euler code