Investigations on wind turbine wakes: wind tunnel tests and field experiments with LiDARs
Event details
| Date | 18.10.2011 |
| Hour | 16:15 |
| Speaker | Dr Valerio Iungo, WIRE-ENAC |
| Location |
GR C0 01
|
| Category | Conferences - Seminars |
Wind energy has been growing rapidly in the last few decades and is becoming one of the most profitable source of renewable energy, thus more efficient and optimized wind energy systems are needed. Investigations on wake flows produced from the interaction between atmospheric boundary layer and wind turbines can be carried out with numerical simulations; however, all numerical tools need a significant amount of experimental data for their assessment and validation. Experimental investigations on wind turbines mainly consist of wind tunnel tests and field measurements of real wind turbines: the former presents the advantage of reproducing a broad range of well characterized wind conditions, but the down-scaled models used for these investigations can represent a strong limitation due to a lower Reynolds number with respect to real conditions. On the other hand field measurements of real wind turbines still represent a challenging task due to the large measurement volumes involved and to the high financial effort. In this study wind tunnel investigations carried out by using hot-wire anemometry and multi-hole pressure probes are presented. Analysis of the development of wind turbine wakes by moving downstream and of the evolution of turbulence highlights that wind turbine wakes are characterized by a strong velocity defect in the proximity of the rotor; moreover, the wake velocity defect and the cross-dimension of the wake are found to be related to wind turbine performance. Besides wind tunnel tests, field measurements of wake flows produced from two 2 MW wind turbines located in Valais, Switzerland, are performed with three wind LiDARs. Bi-dimensional scans are performed in order to analyse wind turbine wakes and simultaneous measurements with two or three LIDARs allow the reconstruction of multi-component velocity fields. Interestingly, both LiDAR and wind tunnel measurements highlight the presence of an increased turbulence level at the top-tip of the wind turbine blades, which can represent dangerous fatigue loads on following wind turbines within a wind farm.
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Practical information
- General public
- Free
Contact
- Prof. Fernando Porte-Agel