Non-linear analysis of stall flutter based on the ONERA aerodynamic model

Abstract

AbstractThis paper presents a simple and efficient way of calculating stall flutter using the ONERA aerodynamic model. At first, the model is presented along with a solution technique based on the harmonic balance method. The parameters of the model are estimated using data either from experiments or CFD calculations and optimised using the Levenberg-Marquardt algorithm. The aerodynamic model is then coupled with a structural one using the Rayleigh-Ritz formulation and a solution technique is devised based on the Newton- Raphson method. Finally the model is used to ‘fit’ aerodynamic loads of oscillating aerofoils generated using CFD. The aeroelastic analysis of a helicopter blade is finally undertaken using material properties found in the literature. The model appears to be robust and efficient and able to fit the unsteady aerodynamics of various cases. The proposed aeroelastic analysis was also found to be efficient and capable of providing adequate results for preliminary analysis of stall flutter.