Room:
Diesel Hall
Topic:
B. Wind, wakes, turbulence and wind farms
Form of presentation:
Oral
Duration:
90 Minutes
Chaired by: J. Meyers, J. Peinke
16:30
Wind turbine wake measurement in complex terrain
Kurt S. Hansen | Technical University of Denmark | Denmark
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Authors:
Kurt S. Hansen | Technical University of Denmark | Denmark
Gunner Chr. Larsen | Denmark
Robert Menke | Denmark
Nikola Vasiljevic | Denmark
Nikolas Angelou | Denmark
Ju Feng | Denmark
Andrea Vignaroli | Denmark
Chang Xu | Denmark
Wei Liu | Denmark
Wen Zhong Shen | Denmark
SCADA data from a wind farm and high frequency time series measurements obtained with remote scanning systems have been analysed with focus on identification of wind turbine wake properties in complex terrain. The analysis indicates that within the flow regime characterized by medium to large downstream distances (more than 5 diameters) from the wake generating turbine, the wake changes according to local atmospheric conditions e.g. vertical wind speed. In very complex terrain the wake effects are often overruled by distortion effects due to the terrain complexity or topology.
16:50
Investigations into the Interaction of a Wind Turbine with Atmospheric Turbulence in Complex Terrain
Dr. Thorsten Lutz | University of Stuttgart | Germany
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Authors:
Dr. Thorsten Lutz | University of Stuttgart | Germany
Levin Klein | Germany
Pascal Weihing | Germany
Christoph Schulz | Germany
This paper deals with the Delayed-Detached-Eddy-Simulations (DES) of a generic 2.4MW wind turbine in a complex terrain site facing a turbulent atmospheric boundary layer. The boundary layer is generated based on measurement data derived at the complex terrain site. Further, the process of data preparation as well as the numerical setup are described. In the results the impact of complex terrain on the flow field is shown and estimations on the influence on the turbine performance are made. Afterwards, simulations of the turbine facing atmospheric inflow in flat and complex terrain are presented. An increase of loads resulting from a speed-up caused by the terrain as well as a change in the power spectrum become visible in complex terrain compared to flat terrain. This finding is in agreement with the estimations derived previously. Moreover, the impact of inclined inflow caused by the local terrain slope can be seen in the load distribution vs. the azimuth angle, amongst others.
17:10
Study of the wind flow over a double-ridge site with numerical simulations using a coupling approach and multi-lidar field measurements
Dr. Carlos Veiga Rodrigues | University of Porto, Faculty of Engineering (FEUP) | Portugal
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Authors:
Dr. Carlos Veiga Rodrigues | University of Porto, Faculty of Engineering (FEUP) | Portugal
José Palma | Portugal
Nikola Vasiljevic | Portugal
Michael Courtney | Portugal
Jacob Mann | Portugal
The wind flow over a double-ridge site has been numerically simulated with a nested model-chain coupling, down to horizontal resolutions of 40 m. The results were compared with field measurements attained using a triple-lidar instrument, the long-range WindScanner system, which allowed measurements up to 500 m height and the mapping of the wind speed onto a two-dimensional transect crossing the valley. The site, known as Serra do Perdigão, is located in central Portugal and consists of two parallel ridges 1.4 km apart with height differences of 200 m in between, being characterized by rough terrain and forested areas. The analysis was restricted to June 10th 2015, for which measurements and simulations both predicted gravity wave activity, the later showing formation of rotors in the lee of both ridges and some events of wave breaking above the ridge top.
17:30
The effects of the canopy created velocity inflection in the wakes development of a large wind turbine array
Oxana Agafonova | Lappeenranta University of Technology | Finland
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Authors:
Oxana Agafonova | Lappeenranta University of Technology | Finland
Anna Avramenko | Finland
Ashvinkumar Chaudhari | Finland
Antti Hellsten | Finland
Large Eddy Simulations (LES) are carried out using OpenFOAM to investigate the canopy created velocity inflection in the wake development of a large wind turbine array. Simulations are performed for two cases with and without forest separately. Results of the simulations are further compared to clearly show the changes in the wake and turbulence structure due to the forest. Moreover, the actual mechanical shaft power produced by a single turbine in the array is calculated for both cases. Aerodynamic efficiency and power losses due to the forest are discussed as well.