Investigation of the impact of planetary boundary layer turbulence on the performance of onshore wind farm

Abstract

Abstract In recent years, wind power has become the fastest growing renewable energy. In the wind power generation, wind energy assessment is also a crucial one, it is directly related to the layout and power generation forecast of a wind farm. Before a wind park is constructed, a site with high mean annual wind speeds in hub height has to be found. To analyse the wind resources at a potential wind park site the three-dimensional wind field has to be simulated. In this paper, accurate and reliable Computational Fluid Dynamics (CFD) simulations of wind flow over natural complex terrain in northern of Morocco have been performed. The Geographic Information System (GIS) is used to generate contour elevation data before can be directly imported into CAD to generate terraced three-dimensional topographic map of test area. The site is characterized regarding its flow features and the suitability for a wind turbine test field. An improved delayed detached eddy simulation (IDDES) was employed using measurement data to generate generic turbulent inflow. A good agreement of the wind profiles between the different approaches was reached. The terrain slope leads to a speed up, a change of turbulence intensity as well as to flow angle variations. For the numerical simulation the Open Source Computational Fluid Dynamics (CFD) Toolbox OpenFOAM (Open Field Operation and Manipulation) was used. It is a compressible finite volume flow solver using block-structured grids and featuring a wide range of turbulence models. This type of analysis may help in preliminary assessments and expedite the site selection process.