Experiments on the Helicopter-Obstacle Aerodynamic Interference in Absence of External Wind

The rotor-obstacle interaction has become a challenging research topic in the last few years. In the present paper a comprehensive experimental survey carried out at University of Glasgow is described, taking advantage of two different rotor rigs and several experimental techniques. The results are then compared with those already obtained for a similar investigation at Politecnico di Milano. 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), Laser Doppler Anemometry (LDA) measurements of the rotor in ow and Stereoscopic Particle Image Velocimetry (SPIV) measurements in the region between the rotor and the obstacle. Despite a few slight differences in geometry and test conditions, the two databases show several similarities that are analysed in the paper.