Validation of rotor aerodynamics predictions of hingeless rotor using a flexible multi-body approach

This paper presents validation of the rotor aerodynamics in descending flight for a hingeless rotor using a flexible multi-body dynamic analysis. In the present computational model, an extended mixed variational formulation was derived to consider the multi-body components as individual beam elements. Thus complex rotor system, such as bearingless rotor, can be also analyzed by the present approach. Structural model was developed using the geometrically exact beam formulation. Various low-order inflow aerodynamics models, such as uniform, linear, and finite state dynamic inflow combined with blade element theory, were used. The present structural model features advantages that displacements, inertial forces, and momenta can be directly extracted and solved simultaneously. Finite state dynamic inflow aerodynamics was used to predict induced inflow in descending flight condition. It calculates unsteady aerodynamics and will cost less computational time than the other wake models do. The present results are compared by experimental data on HART II rotor.