LAUNCH VEHICLE SELF-SUSTAINED OSCILLATION FROM AEROELASTIC COUPLING PART 2 - ANALYSIS

Aeroelastic theory developed in a companion paper is applied to the an alysis of a launch vehicle mission, and the corresponding loads are co mpared with those for other transonic events. Limit cycle amplitudes a re computed for several payload fairing lengths using both the present theory and the classical approach for analysis of launch vehicle aero elastic coupling. The present theory explicitly identifies a generaliz ed time lag as the critical parameter for aeroelastic coupling. The am plitude of the self-sustained oscillation can be significantly smaller than that predicted by the so-called stability criterion in the class ical theory, depending on the value of this parameter The single mode representation for launch vehicle aeroelastic analysis is assessed thr ough transient analysis of the fully coupled system. It is shown that higher order Fourier components of the oscillating how forces can exci te system modes other than the bending mode, which was expected to dom inate the coupling. Data exhibiting oscillating flow states during a f light of the Titan IV launch vehicle are presented.