Detailed induction zone wind field measurements over sloping terrain

T.K. Mikkelsen, C.M. Sjöholm, P. Astrup, M F van Dooren, A.P.Kidambi Sekar

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Abstract

High-resolution 3D wind field measurements scanned upwind in the induction zone of an 850 kW- 52m Ø DTU test wind turbine (Vestas V52) is presented.
Two high-resolution synchronized lidars[1] (6” short-range WindScanners) scanned the inflow in a 2D vertical plane between the turbine rotor and an upwind the met-mast at +2.2D. A DTU SpinnerLidar installed on top of the turbine nacelle scanned the wind field crosswind within the rotor plane at +1D.
The lidar scanned wind field measurements are compared with the met-mast vertical wind profile measure at five heights with sonic anemometers within the rotor area.
Two case studies have been analysed and will be presented, both obtained during periods where the mean wind direction aligned favourable (within a few degrees) of the met-tower turbine connection line have been analysed. One, characterized by high strong winds, obtained June xx.? 2018 (with average wind speed 17 m/s) and another, obtained on December 10. 2018 (with average wind speed about 10 m/s), have subsequent been analysed.
During Westerly winds (280 degrees ?) the turbine, installed 9 m above sea level, experiences heterogeneous inflow through the met-mast at +2.2D and installed at 7 m asl, and furthermore upwind the inflow is influenced by a relative steep escarpment of approximately 6 m height down towards the fjord at + 4. 3D.
The 2D wind field measured via the vertically scanning with two lidars between the met-mast and the turbine show significant influence by the terrain effects: caused by the escarpment an increased wind speed extended from the ground and up to approximately 40 m height. Nearest to the turbine, the vertical wind component diverges around the rotor. In the along wind component, stagnation can be observed already in the met-tower vertical profiles. At +1D the DTU SpinnerLidar scanned line-of-sight measurements were fed into a 3D wind field reconstruction using the fast cfd code LINCOM[2]. In addition, these measurements show influence of induction-reduced inflow and flow divergence above and below the rotor.
Original languageEnglish
Publication date2019
Number of pages2
Publication statusPublished - 2019
EventWind Energy Science Conference 2019 - University College Cork, Cork, Ireland
Duration: 17 Jun 201920 Jun 2019
https://www.wesc2019.org/

Conference

ConferenceWind Energy Science Conference 2019
LocationUniversity College Cork
CountryIreland
CityCork
Period17/06/201920/06/2019
Internet address

Keywords

  • Induction zone
  • Sloping terrain
  • Wind field scanning
  • Full-scale experimental evaluation

Cite this

Mikkelsen, T. K., Sjöholm, C. M., Astrup, P., van Dooren, M. F., & Sekar, A. P. K. (2019). Detailed induction zone wind field measurements over sloping terrain. Abstract from Wind Energy Science Conference 2019, Cork, Ireland.