Helicopter-obstacle aerodynamic interaction in windy conditions

Abstract

The helicopter-obstacle interaction has become a challenging research topic in the last few years. The detrimental effects which can arise in this kind of aerodynamic interaction can be dramatically worsened under windy conditions, particularly when the helicopter flies inside the turbulent and extremely unsteady wake generated by an obstacle. In the present paper a comprehensive experimental survey carried out at Politecnico di Milano is described, obtained by placing a helicopter model in several positions with respect to an obstacle, in windy and not windy conditions. The experimental database comprises load measurements on the rotor in order to assess the rotor performance for different positions with respect to a cubic obstacle, steady and unsteady pressure measurements on the obstacle and Particle Image Velocimetry (PIV) measurements in the region between the rotor and the obstacle in order to highlight the features of the interacting flowfield.