Analysis of tiltrotor whirl flutter in time and frequency domain

Taeseong Kim, SanJoon Shin, Taehyoun Kim

    Research output: Contribution to journalJournal articleResearchpeer-review


    The whirl flutter phenomenon in a rotor is induced by in-plane hub forces, and imposes a serious limit on the forward speed. In this paper, based on Greenberg’s model, quasi-steady and unsteady aerodynamic forces are formulated to examine the whirl flutter stability for a three-bladed rotor without flexible wing modes. Numerical results are obtained in both time and frequency domains. Generalized eigenvalue solution is utilized to estimate the whirl flutter stability in the frequency domain, and Runge-Kutta method is used to analyze it in time domain. The effects of varying the pylon spring stiffness and the swashplate geometric control coupling upon the flutter boundary are investigated. An optimum pitch-flap coupling parameter is discovered through the parametric study. Aeroelastic stability boundaries are estimated with the three different aerodynamic models. It is found that the analysis with the full unsteady aerodynamics predicts the highest flutter speed.
    Original languageEnglish
    JournalJournal of Mechanical Science and Technology
    Issue number3281-3291
    Publication statusPublished - 2009


    • Aeroelastic design methods
    • Wind Energy


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