A New Actuator Surface Model with Improved Wake Model for CFD Simulations of Rotorcraft

Simulations of rotorcraft operating in unsteady flow-fields, manoeuvring flight, or with complex rotor configurations pose a significant challenge to current simulation methods. Simplified rotor models lack the generality required for the diverse range of operating conditions that a rotor may be exposed to, while higher-fidelity Navier-Stokes CFD simulations with fully-resolved rotors are expensive in terms of computational resources, simulation time, and preprocessing time. Here we present a new rotor and wake model which is fully-coupled to a CFD solver and is based on the actuator surface model. This model is designed to reduce the cost of complex rotorcraft simulations in comparison with fully-resolved simulations and provide greater generality than other rotor models. Results from simulations using the new actuator surface and wake model provide validation of the concept for hover and forward flight. The spanwise loading distribution, thrust coefficient, and wake geometry are shown to be reasonable in comparison with data from experiments, fully-resolved simulations, and prescribed wake models.