Aerodynamic Performance of a Rotor Hovering in Close Proximity to Confined Area Ground

In this study, effects of the confined area geometry on the aerodynamic performance of the hovering rotor are showed from experiments from standpoints of flight safety. The confined area is simulated putting up vertically a single plate or plural plates on the ground effect plate. The aerodynamic performance of the rotor changes because a part of the rotor wake upward along the walls interferes with the flow field around the rotor. It is shown that the behavior of the steady torque coefficients remarkably depends on the combinations among the space between walls, the wall numbers, and the rotor height, and the required torque coefficient increases at all rotor height compared with that above the ground without walls. And also, there is the required torque coefficient in ground effect which can exceed that out-of-ground effect.