Wind Tunnel Investigation of a Helicopter Model in Shipboard Operations

The paper presents the wind tunnel simulation of a helicopter model in shipboard operations. The test rig consists of a scaled helicopter model and a simplified ship model, based on the geometry of the Simple Frigate Shape 1. In the first phase of the experiment, pressure and Particle Image Velocimetry survey of the flow field on the flight deck were performed without the presence of the helicopter, to study the flow features on the ship deck, for several wind conditions obtained modifying the wind speed and direction. The influence of Atmospheric Boundary Layer was investigated as well. Then, the rotorcraft was positioned in a series of points representative of both a typical fore-aft landing trajectory toward the deck, and a vertical descent on the deck. Loads generated by the rotor were monitored by means of a six-axis load cell. Particle Image Velocimetry of the ship wake and of the helicopter inflow were carried out in order to have a better understanding of how the interacting flow fields affected the helicopter performance. The test showed a significant effect of the mutual aerodynamic influence between the helicopter and the ship model and a limited effect of the Atmospheric Boundary Layer