HusumWind 2019

•••2••• Innovationen How wind speeds change Flight data of offshore wind farm measurements published A total of 41 flights with the re- search aircraft of TU Braun- schweig were carried out with great success to measure the wind fields downwind of offshore parks. The research team of the Institute of Flight Guidance at the TU Braunschweig, headed by Professor Peter Hecker, was par- ticularly interested in the investi- gation of long-range wake flows. These can form with stable at- mospheric stratification when warm air flows over the cooler sea surface. The wind speed can be significantly reduced up to 50 kilometres behind the wind farms. Different weather condi- tions and seasons were investi- gated, and the data were evalu- ated together with the project partners. “The project has provided us with important insights that will di- rectly influence the further plan- ning of the North Sea wind farm expansion,” explains Dr. Astrid Lampert, head of the subproject at Technische Universität Braun- schweig. The first results have already been published in several scientific journals and presented at scientific conferences. The pub- lication of the entire data set now enables research groups world- wide to use the data for their own investigations and in particular for the validation of simulations. The findings are of great interest for the further efficient and environ- mentally compatible expansion of offshore wind power. The motivation to launch the “Windpark-Fernfeld (WIPAFF)” project came from satellite imag- es. They showed a change in the roughness of the sea surface be- hind wind farms. Also numerical simulations predicted the exist- ence of far-reaching wakes behind offshore wind parks. Within the framework of WIPAFF, these ef- fects were measured for the first time directly on site on a large scale by airplane. The data were evaluated in combination with other measurement data, satellite images and simulations. The research project is coordi- nated by the Karlsruhe Institute of Technology (KIT). In addition to the Institute of Flight Guid- ance of the TU Braunschweig, the Eberhard-Karls-Universität Tübingen, the Helmholtz-Zentrum Geesthacht and an industrial part- ner are involved. It was funded by the Federal Ministry of Economics and Energy over a period of three years with 1.75 million euros. Zuverl ssige Rotorblattlager für Windenergieanlagen Moderne Windenergieanlagen können die Rotorblät- ter individuell und kontinuierlich den Windbedingun- gen anpassen. Diese kontinuierliche Nachstellung setzt die Rotorblattlager jedoch ständigen oszillie- renden Bewegungen aus. Bei bis zu 80 Meter langen Rotorblättern wirken gewaltige Kräfte auf die Blatt- lager ein, besonders empfindlich ist die Verbindung zwischen Nabe und Rotorblättern. Schäden verursa- chen lange Ausfallzeiten und hohe Kosten. Um Rotor- blattlager zuverlässig zu gestalten und kostenintensi- ve Wartungsarbeiten zu vermeiden, hat sich ein Konsortium aus fünf Forschungsinstituten und vier Herstellern von Windenergieanlagen formiert, koor- diniert vom Institut für Maschinenkonstruktion und Tribologie (IMKT) der Leibniz Universität Hannover. RELIABLADE: increasing reliability of rotor blades Danish DTU Wind Energy and German Fraunhofer Institute for Wind Energy Systems (IWES) have joined forces and nation- al funded projects in the new 17.6 million euros RELIABLADE project. For the project, researchers will develop a blade de- sign for a 40 metre blade. This will serve as a blueprint for manufac- turing two blades at Fraunhofer IWES and challenge them in experimental tests at the DTU in order to intentionally damage them under controlled conditions. “We want to improve the understanding of the structural behaviour of rotor blades. There- fore, we have developed a project in which we have control over the blade design, the manufacturing and the test and can investigate the damage process over the entire blade life with advanced numerical and ex- perimental methods.” Fraunhofer IWES in Bremerhaven Photo: Jan Meier Race Bank offshore wind farm, 27 km off the coast of Norfolk, United Kingdom Photo: Nicholas Doherty on Unsplash Continued from page 1