Helicopter Rotor Loads Prediction and Validation Based on a Fully Nonlinear Aeroelastic Method

Abstract

State-of-the-art helicopter rotor simulations reveal that the prediction accuracy of aerodynamic and structural main rotor loads is still insufficient. In particular, deficits are apparent in simulations of flight conditions on the edge of the flight envelope -such as high-thrust forward flight with three dimensional flow separation on the retreating blade. This work presents numerical approaches for the improved prediction of helicopter rotor loads. Using high-fidelity validated CFD-MBS methods have been enhanced the accuracy of aeroelastic simulations compared to state-of-the-art. The research contains the analysis of the structural blade dynamics isolated from the aeroelastic helicopter response problem. Investigations of the aeroelastic rotor behavior are based on tightly-coupled simulations between an unstructured CFD solver and a Multibody Software (MBS) using the previously validated structural rotor blade models. The rotor predictions were assessed with aerodynamical and structural data gained from European wind tunnel measurements.