NONLINEAR ROTOR AEROELASTIC ANALYSIS WITH STALL AND ADVANCED WAKE DYNAMICS

This paper studies an effective lag damping prediction method for a fl exible flap-lag-torsional hingeless rotor model and correlation with t he 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 s tate variables with 4 x 10 structural state variables. Eight aerodynam ic elements for each rotor blade and at least eight wake harmonics are employed, The aerodynamic and wake state variables are 4 x 48 and 45, respectively. A numerical simulation technique is applied to determin e the transient response of the hingeless rotor model and to predict t he lag damping. Numerical investigations indicate that the present the oretical/numerical method improves the correlation of the theoretical and experimental results compared to an earlier eigenvalue, perturbati on analysis.