Wake characteristics of an offshore wind turbine in the vicinity of a coastal mountain

An extensive set of experiments was carried out in the CRIACIV boundary layer wind tunnel in order to characterize flow and turbulence around an offshore wind turbine in complex coastal terrain. The wind-tunnel simulation of the atmospheric boundary layer (ABL) flow and turbulence developing upwind from the coastal mountain was achieved by using the castellated barrier wall, vortex generators and surface roughness elements. Once a well developed ABL simulation has been created, wake characteristics of an alone-standing offshore wind turbine were studied for three different mountain models (small and large mountain with laterally uniform height, mountain with a bay). A configuration without the mountain was tested as well in order to investigate flow and turbulence around an offshore wind turbine placed downstream of a plane coast. The wind turbine was in the parking position (no rotation of the rotor blades) in order to study wind characteristics for a strong wind situation with wind velocity larger than 25 m/s. The experimental results indicate a velocity decrease and stronger turbulence in the wind-turbine wake in presence of a coastal mountain.