Abstract
The wake characteristics of a hill-top wind turbine are investigated by means of large-eddy simulations (LESs) of stably stratified atmospheric boundary-layer (ABL) flows. All simulations are conducted with synchronized turbulent inflow data retrieved from an LES of diurnal cycle-driven boundary-layer flow over homogeneous surface. An investigation of different (weak, moderate, strong) stably stratified flow regimes passing over various 3D hill configurations with heights up to 50 m reveals that the occurrence of flow separation not only depends on hill properties but also on the atmospheric stratification. The hill-top wake characteristics of all flow regimes are compared with wakes resulting from the same flow fields passing through the same wind turbine, however, sited on a homogeneous surface. For the same atmospheric stratification the flow over the hill impacts only the near-wake region. In contrast, the stratification impact on the hill-top wind-turbine wake is much more distinct, especially, in the far wake.
Highlights
A detailed understanding of wind-turbine wakes is essential to increase the wind-energy contribution to the world-energy demand in the future
The numerical study presented in this paper focuses on the wind-turbine wake characteristics, influenced by a turbulent flow over a 3 D isolated hill for different stably stratified atmospheric boundary-layer (ABL) regimes
The wind-turbine wakes over homogeneous surface corresponding to the morning boundary layer (MBL) and the evening boundary layer (EBL) are comparable to the stable boundary layer (SBL), with a slightly longer wake extension and larger velocity deficit values for the MBL (EBL)
Summary
A detailed understanding of wind-turbine wakes is essential to increase the wind-energy contribution to the world-energy demand in the future. More precise knowledge about the wake of a wind turbine responding to ABL flow under different thermal stratifications in complex terrain is necessary. This will help to extend the lifetime of a wind turbine and to improve the performance of wind farms. The deformation of the wind while passing over hilly terrain increases the turbulence and advects it leewards into possible wind-turbine wakes [1], [2]. Considering the ABL, the ambient turbulence impacts the fatigue loading of a wind turbine and controls the entrainment of ambient air into the wake and, its characteristics. Transitional periods in the evening and the morning follow the respective flow regime prior to the transition [6]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
