Application of Finite-State Wake Models to Rotors Reentering Their Own Wake

This paper details the development of a finite-state, dynamic wake model for the purpose of modeling a helicopter rotor reentering their own wake. This model stems directly from both the Peters-Morillo wake model to determine the velocity field on and above the helicopter rotor and the Peters-Fei model to compute the velocity field below the rotor. The specific case of nonzero net thrust was evaluated, under assumptions of axial flow (relative to the rotor) and potential flow theory. Results consist of computations of the inflow velocity for this case, along with comparison to closed-form, potential flow solutions for validation. The finite-state model is shown to converge with the closed-form solutions up to 10 states prior to increasing divergence with an increasing number of states.