Validation of a cost effective method for the rotor-obstacle interaction

Abstract Helicopter flight in proximity to the ground and to rectangular obstacles is addressed in the paper. The work aims at first evaluating the capabilities of a medium fidelity simulation model to reproduce the effects on the loads of a helicopter main rotor, when it executes a hover flight close or above an obstacle of well defined geometry and second, at characterizing the flow field in the wake of the helicopter as it interacts with the obstacle and the ground. Detailed characterization and classification of the interactional phenomena occurring between the rotor and its wake and the obstacle is performed with main parameter their relative position. Moreover, simulations are carried out with a free wake model combined with a cost saving particle mesh technique for the treatment of the wake evolution and predictions are compared against two different experimental databases. Both experimental campaigns concern scaled helicopter models hovering above a rectangular box and have been performed at Politechnico di Milano and at the University of Glasgow respectively.