Nonlinear reduced-order modeling of the forced and autonomous aeroelastic response of a membrane wing using Harmonic Balance methods.

A nonlinear reduced-order model for a membrane wing at low Reynolds numbers is obtained by coupling a linear aerodynamic model with a nonlinear one-dimensional membrane equation. Steady-state solutions for the membrane's aeroelastic response are obtained by means of Harmonic Balance methods in the frequency-domain and in the time-domain. Harmonic Balance methods are adopted to investigate the aeroelastic response of a membrane wing pitching about its leading-edge at R e = 100 , for different values of the pitching angle. Differences between the two Harmonic Balance approaches are discussed and validations of the methods are carried out using high-fidelity Direct Numerical Simulations. The effect of the Reynolds number on the wing's lift response is taken into account by increasing the Reynolds number to R e = 1000. Harmonic Balance methods are also used to analyze the limit-cycle autonomous oscillations of the membrane for linearly unstable cases. The frequency of the oscillations can be predicted by introducing a frequency-searching algorithm in the solution procedure. [ABSTRACT FROM AUTHOR]