Wind flow in complex terrains is characterized by strong unsteady phenomena and multi-scale characteristics

which makes accurate simulation difficult and hinders the refined assessment of wind resources. In order to take into account both the mesoscale atmospheric circulation and the microscale unsteady flow details

this paper couples the mesoscale weather research and forecasting (WRF) model and the microscale computational fluid dynamics (CFD) technology to construct an unsteady modeling framework for complex terrain wind farms. The international classic cases of Askervein Hill and Bolund Island are used as the validation cases to study the vertical distribution of mean wind speed and turbulence intensity in the complex terrain flow field

and the strategy of wind turbine layout in complex terrains is briefly analyzed. The results show that the numerical simulation results based on the coupled WRF-CFD framework for unsteady flow modeling are in good agreement with the experimental observations

and the absolute error of the wind speed is within 2 m/s in the selected locations of the characteristic point

which is better than that of the mesoscale numerical simulation alone. The methodology in this paper can also provide input conditions for wind turbine design

layout

load assessment as well as wind farm operation control.