Papers Published

1. Tang, D.M. and Dowell, E.H., Comparison of theory and experiment for nonlinear flutter and stall response of a helicopter blade, Annual Forum Proceedings - American Helicopter Society (1991), pp. 1413 - 1425 .
   (last updated on 2007/04/10)

   Abstract:
   The purpose of the present paper is to study the flutter instability and forced response of a non-rotating helicopter blade model with parabolic and freeplay torisonal stiffness nonlinearity based upon the (linear and) nonlinear ONERA stall aerodynamic model. An experiment has also been carried out in the Duke University low speed wind tunnel. The wind tunnel tests show good agreement between theory and experiment for linear and nonlinear flutter instability; for periodic, limit cycle and chaotic flutter motion and forced response behavior; and for the effects of initial disturbance on nonlinear flutter instability. Comparisons of the results of the theory and the experiment are helpful in understanding physically the nonlinear aeroelastic phenomena and chaotic oscillations.

   Keywords:
   Turbomachinery - Blades;Aerodynamics - Flutter;Wind Tunnels - Applications;