Some experience using subcritical response methods in wind-tunnel flutter model studies

Experiences obtained with four methods of predicting flutter of wind-tunnel models from subcritical response data are described. The four methods are: co/quad, randomdec, power spectra density, and the peak-hold spectrum. Model excitation techniques included both forced (sinusoidal sweep) and random (tunnel turbulence). These methods were successfully used to measure the frequency and damping (or an inverse response amplitude proportional to the damping) in the predominant flutter modes. Implementation and application of each method are discussed. Some results and comparisons between methods are presented.