Experimental study of a helicopter model in shipboard operations

The paper presents the experimental investigation of the aerodynamic interaction between a helicopter model and a ship model with a simplified geometry. In the first phase of the experiment, a series of wind tunnel tests were carried out in order to study the flow features on the flight deck for several wind conditions, without the presence of the helicopter. Pressure measurements and Particle Image Velocimetry surveys were performed to assess the effect of wind velocity and direction on the flow field in the landing region over the ship deck. Moreover, the effect of the Atmospheric Boundary Layer was investigated. In the second phase of the experimental campaign, a helicopter model was positioned in a series of points representative of a typical stern landing trajectory and a vertical descent above the landing spot. The landing maneuver was performed in three different wind conditions, including no-wind, head wind and wind blowing from port side of the deck. The rotor loads and moments were measured by means of a six-axis balance for all test points. The use of different measurement techniques in the present experiments provides a comprehensive database suitable for the study of the rotor-ship aerodynamic interaction. Additionally, the experimental results are used to develop an identification algorithm to be incorporated into the flight simulator environment to capture the effect of ship airwake on the rotor loads during shipboard operations.