Wind Energy Research News from Forwind Institute, Oldenburg
by Jana Stone, ForWind – Zentrum für Windenergieforschung
Higher energy output from wind farms
The Center for Wind Energy Research (ForWind) is partner in the joint project "CompactWind II", which will receive a total of 1.4 million euros in funding from the Federal Ministry of Economics and Energy (BMWi) over the next three years. The project aims to minimize the negative wake effects in wind parks in order to increase energy yield and reduce loads. This would allow more output to be achieved while maintaining the same base area of the wind farm. Under the project management of eno energy systems GmbH, Rostock, ForWind, the Department of Wind Energy at the Technical University of Munich (TUM), and fos4X GmbH, Munich, are involved. The project partners intend to use computer simulations, model tests in wind tunnels and free-field experiments on real turbines to test the new control procedures using the most modern methods available.
Installation of control set-up on top of a wind turbine
Particle image velocimetry (PIV) in the large Oldenburg wind tunnel
How does the wind flow around the rotor blade of a wind turbine? What does this flow look like when a gust of wind hits the blade? In order to answer these and other questions, ForWind scientists are conducting experiments in the large Oldenburg wind tunnel. With the help of an active grid, turbulent currents can be generated to which a model wind turbine is exposed. A laser makes tiny particles added to the air visible, and high-speed cameras record the movements of the particle streams. With this method, known as particle image velocimetry (PIV), the particles of an entire flow field that passes the blade are photographed and the flow direction and velocity are calculated from the change in their position from one photo to the next. The cameras take up to 12,000 images per second. The Oldenburg scientists have now succeeded in applying this measurement method to a rotating model wind turbine in a large wind tunnel with turbulent flows. These were the first wind tunnel experiments within the research project "TurbuMetric – Optical 3D measurement systems for coverage dynamic fluid-structure-interactions while turbulent wind surroundings" (https://turbumetric.de). TurbuMetric is a joint research project of the Jade Hochschule and the University of Oldenburg and funded by the European Regional Development Fund (ERDF). The results show how the wind flows around the moving rotor blade. The scientists are particularly interested in when and how the flow breaks off from the rotating blade and which wind situations lead to the largest impacts and thus to the greatest dynamic loads on the components of the wind turbine. In the wind tunnel, the measurements can be reproduced under controlled conditions. For example, the scientists can carry out several tests with the same turbulent wind field. Since they can only measure in a thin light section with the standard method, the researchers are already working on a further development of the PIV method: Holography will be used to measure three-dimensional flow fields.
Experimental setup in the Oldenburg wind tunnel with model wind turbine MoWiTO 1.8 (rotor diameter 1.8 meters), laser and active grid (Photo: J. Puczylowski, ForWind)
New ForWind member and newly elected Executive Board Spokesman
At the meeting of the ForWind Executive Board on March 14, 2019, Prof. Dr. Jürgen Peissig from the Leibniz University Hannover was welcomed as a new member at ForWind. Peissig is head of the department "Communication Systems" at the Institute of Communications Technology. Thus, a total of 30 working groups and institutes of the universities of Oldenburg, Hannover and Bremen are currently members of ForWind.
At the Executive Board meeting Prof. Dr.-Ing. Peter Schaumann was elected as new spokesman and Prof. Dr. Joachim Peinke as second spokesman. The Executive Board of ForWind consists of two members each from the Carl von Ossietzky University of Oldenburg, the Leibniz University of Hannover and the University of Bremen. The current board consists of Prof. Dr. Martin Kühn (Oldenburg), Prof. Dr.-Ing. Bernd Orlik (Bremen), Prof. Dr. Joachim Peinke (Oldenburg), Prof. Dr.-Ing. habil. Raimund Rolfes (Hannover), Prof. Dr.-Ing. Peter Schaumann (Hannover) and Prof. Dr.-Ing. Klaus-Dieter Thoben (Bremen).
Research cooperation with Taiwan
In March ForWind scientists visited the National Cheng Kung University (NCKU) in Tainan, Taiwan, as part of a long-term international cooperation. As a contribution to a national research project of the Taiwanese partners, the sphere anemometer developed in the Oldenburg working group TWiSt (Turbulence, Wind Energy and Stochastics) was adapted for use in extreme wind conditions such as typhoons. In an on-site measurement campaign, two configurations of the anemometer were measured in the wind tunnel at wind speeds of up to 70 m/s. The program of the week was supplemented by three lectures in the context of a workshop on "Extreme Wind Speed Measurements and Atmospheric Turbulence in Wind Energy Applications" at the NCKU as well as an overview lecture by Joachim Peinke at the state-owned energy supplier Taipower on the main research areas and expertise of wind research in Oldenburg.
Left picture: sphere anemometer developed at Forwind, Ol / Right picture: Forwind Scientists (a.o. Dr. Mike Hölling – PPRE-lecturer 3rd from right) with local researchers at NCKU, Taiwan
ForWind research topics at the Wind Energy Science Conference
You are planning to attend the Wind Energy Science Conference WESC in Cork in June this year? Come and join us for the Mini Symposia with ForWind research topics „Wind Tunnel Experiments“ (Chair: Hendrik Heißelmann, Co-Chair: Michael Hölling) and „Mesoscale Modelling of Wind Resources“ (Chair: Björn Witha, Co-Chair: Andrea Hahmann)!