Papers Published

1. Tang, Deman and Dowell, Earl H., Nonlinear rotor aeroelastic analysis with stall and advanced wake dynamics, Journal of Aircraft, vol. 34 no. 5 (1997), pp. 679 - 687 .
   (last updated on 2007/04/10)

   Abstract:
   This paper studies an effective lag damping prediction method for a flexible flap-lag-torsional hingeless rotor model and correlation with the experimental data for a four-bladed rotor. The ONERA dynamic stall models of lift, drag, and pitching moment for each aerodynamic airfoil element and an advanced three-dimensional finite state wake model are used. The nonlinear equations of motion are represented in terms of state variables with 4×10 structural state variables. Eight aerodynamic elements for each rotor blade and at least eight wake harmonics are employed. The aerodynamic and wake state variables are 4×48 and 45, respectively. A numerical simulation technique is applied to determine the transient response of the hingeless rotor model and to predict the lag damping. Numerical investigations indicate that the present theoretical/numerical method improves the correlation of the theoretical and experimental results compared to an earlier eigenvalue, perturbation analysis.

   Keywords:
   Flexible structures;Flight dynamics;Damping;Lift;Drag;Airfoils;Wakes;Computer software;Computer simulation;Equations of motion;Nonlinear equations;Mathematical models;