Ice Accretion Effects on Helicopter Rotor Performance, via Multibody and CFD Approaches

A numerical approach for assessing the degraded aerodynamics and flight characteristics of ice-contaminated helicopter rotors is proposed. A hybrid two- and three-dimensional loose coupling strategy between multibody dynamics modeling and computational fluid dynamics icing is formulated that attempts to balance computational resources, model complexity, and accuracy for use during the early design phases. A quasi-3D formulation that considers the heat transfer and the motion of the water film due to centrifugal effects is introduced. The method is suited for the analysis of rime, glaze, and/or mixed ice conditions. Degraded aerodynamic and dynamic characteristics of the iced rotor and the changes in flight performance are assessed. The technique has been applied to the scenario of isolated helicopter rotors in hover and in forward flight. Deterioration of the figure of merit is also presented.