Abstract
The nonlinear coupling between the aerodynamic load and structural motions in the experiments conducted in the Langley Transonic Dynamics Tunnel at NASA Langley Research Center on a flexible semispan model (FSM) of a high-speed civil transport wing configuration is examined. The results show that, right before "hard" flutter took place, the aerodynamic load and the structural motion of the FSM were intermittently and quadratically coupled. Particularly, the shock motion, which can be caused by local and intermittent flow separation, is nonlinearly related to the structural motion in such a manner that one full cycle of the shock motion is related to two cycles of the acceleration of the wing tip. Because of the required averaging in implementing them, Fourier-based higher-order spectral moments could not characterize this coupling. On the other hand, the wavelet-based cross bicoherence is established as a tool that is capable of detecting intermittent or transient nonlinear aeroelastic phenomena as would be encountered in model studies or flight tests.
Original language | English |
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Pages (from-to) | 1082-1088 |
Number of pages | 7 |
Journal | Journal of Aircraft |
Volume | 43 |
Issue number | 4 |
DOIs | |
State | Published - 2006 |