ESRIG-EES colloquium: Freek Janssen, MSc EES student
| When: | Tu 01-05-2018 16:00 - 17:00 |
| Where: | 5159.00110 (Energy Academy Building, Nijenborgh 6) |
Title: New wind turbine based on lift enhancement due to oscillation.
By: Freek Janssen, MSc EES student
Summary:
One of the similarities between the fulmar and the albatross is the unusual technique of take-off and landing, called fanning \cite[]{Ruppell}. When the bird approaches the ground, the wings fulfill a fast oscillating rotatory motion. Due to fanning, the aerodynamic coefficients of the wing increase. The angle of attack of the wing increases, which causes an increase in lift. However, the wing reaches stall fast, which means that the lift reduces again and drag increases. Just before the wing reaches stall, the wing returns back to the original angle of attack, which avoids that the wing will be in stall.
In previous studies, it is tested whether this technique would improve the lift to drag ratio of a wind turbine blade as well. This is tested experimentally, with a blade in a flow channel. Also, numerical studies were done. The results of these studies were not unison.
This study is done to proof the concept of lift enhancement due to oscillation in a real wind turbine. In contrast to previous studies, the blades rotate as well. A real wind turbine is built and is tested in a wind tunnel. The main question, whether the power output of a wind turbine that uses this technique is higher or lower than a wind turbine which has fixed blades, can clearly be answered. Higher. This study shows that the concept works. There is a clear difference in power output between the oscillation frequencies and different amplitudes that are tested for the oscillation of the blade. The power increase is a factor 5 for low wind speeds (2.7 m/s) to almost a factor 2 for higher wind speeds (4.5 ms).