Frequency domain flutter solution technique using complex mu-analysis

Appling perturbation to dynamic pressure in the nominal aeroelastic equation of motion, a mu-omega method is presented for flutter solution. Utilizing the structured singular value mu as stability margin indicator, this method simply employs frequency domain aerodynamics to predict the nominal flutter margin through frequency domain mu-analysis. The error of flutter dynamic pressure is selected as convergence criterion during iterations. Discontinuity of the real mu with respect to purely real perturbation is found in a two dimensional wing model with steady aerodynamics when using mu-omega method. To prevent this problem, complex perturbation to dynamic pressure is considered mathematically and the complex mu-analysis is employed in this study. Numerical examples demonstrated that the flutter results obtained by the mu-omega method correlate well with those of the p-k method.