Assessment of Ice Accretion Effects on Rotor Dynamics via Multi-Body and CFD Approaches

A numerical approach is outlined to determine the degraded performance and changes in flight characteristics of a helicopter rotor due to icing. The methodology loosely couples a multibody dynamics code and a Computational Fluid Dynamics-based ice accretion code in an effort to reach a compromise between computational resources and model accuracy. Ice accretion is calculated at several radial sections in a quasi-3D analysis. The dynamics code then determines the degraded flight conditions of the helicopter. Ice shedding from the rotor is addressed through a simplified model which predicts shedding through a computation of cohesion and adhesion stresses due to centrifugal loading. The technique has been applied to a helicopter rotor blade in hover flight, demonstrating an increase in torque and a significant loss in the figure of merit.