Abstract
Super-large-scale particle image velocimetry using natural snowfall is used to investigate the influence of nacelle and tower generated flow structures on the near-wake of an operational 2.5 MW wind turbine. The measurement provides the velocity field over the entire rotor span in a plane centered behind the support tower, revealing a region of accelerated flow around the nacelle and a reduction in velocity behind the tower, causing asymmetry in the velocity deficit profile. The in-plane turbulent kinetic energy field shows increased turbulence in the regions of large shear behind the blade tips and nacelle, and a reduction in turbulence behind the tower. The nacelle wake meandering frequency is found to scale with the nacelle dimension rather than the rotor dimension, corresponding to the vortex shedding frequency of an Ahmed body. Persistent nacelle wake deflection is observed and shown to be connected with the turbine yaw error. Strong interaction between the tower- and blade-generated structures, quantified by the co-presence of two dominant frequencies, demonstrates the influence of the tower on blade tip vortex breakdown. This study highlights the influence of the tower and nacelle on the behavior of the near-wake, informing model development and elucidating the mechanisms that influence wake evolution.
| Original language | English (US) |
|---|---|
| Article number | 103981 |
| Journal | Journal of Wind Engineering and Industrial Aerodynamics |
| Volume | 193 |
| DOIs | |
| State | Published - Oct 2019 |
Bibliographical note
Funding Information:This work was supported by the National Science Foundation CAREER award (NSF-CBET-1454259), Xcel Energy through the Renewable Development Fund (grant RD4-13) as well as IonE of University of Minnesota. We also thank the faculties and engineers from St Anthony Falls Laboratory, including M. Guala, S. Riley, J. Tucker, C. Ellis, J. Marr, C. Milliren and D. Christopher for their assistance in the experiments.
Funding Information:
This work was supported by the National Science Foundation CAREER award ( NSF-CBET-1454259 ), Xcel Energy through the Renewable Development Fund (grant RD4-13 ) as well as IonE of University of Minnesota . We also thank the faculties and engineers from St Anthony Falls Laboratory, including M. Guala, S. Riley, J. Tucker, C. Ellis, J. Marr, C. Milliren and D. Christopher for their assistance in the experiments.
Publisher Copyright:
© 2019 Elsevier Ltd
Keywords
- Super-large-scale particle image velocimetry
- Turbine nacelle
- Turbine tower
- Utility-scale wind turbine wake
