Impact of Wind Energy Rotor Wakes on Fixed-Wing Aircraft and Helicopters

Abstract

The wake of wind energy rotors is modeled as a tip vortex helix with a vortex strength estimated from its rotor thrust. A fixed-wing sail plane and a helicopter whose rotor is represented as a fixed-wing circular disk (instead of rotating blades) are subjected to the wake. In both cases the roll moment induced by the wake is compared to the maximum roll control moment of the aircraft. For comparison with revolving blades, the blade element momentum theory is applied to the isolated rotor and a simulation of an entire helicopter is used also. It is found that typical on-shore power plants could be a hazard for sailplanes, but not for helicopters. Large off-shore wind energy converters, however, could even be a danger for small helicopters that may be used for maintenance.