Aeroelastic Stability of Wind Turbines

Project Description

There is an ongoing trend of increasingly slender and flexible rotor blades in wind turbine development. Consequently, the governing natural frequencies of the rotor blades decrease. The bending and torsional natural frequencies can approach each other in such a way that the risk of bend-twist flutter (and other instabilities) increase. This can especially be critical for so-called "Smart Blades", in which active and passive deformation couplings are integrated.

This research project, which is integrated in the coordinated research project "SmartBlades2", deals with the simulation-based treatment of instability effects. For this purpose, runaway scenarios (besides other aeroelastic test cases) are investigated for the reference turbine model IWT-7.5-164 using the tool OpenFAST. The simulation results are compared with those of the project partners, who use different simulation tools. By this coordinated code-to-code comparison we try to figure out the relevance of modeling differences for the prediction of aeroelastic instabilities. Besides the reference turbine, configurations with geometric bend-twist coupling (so-called "Swept Blades") and with integrated trailing edge flaps are investigated.

The project is integrated in the coordinated research project "SmartBlades2" as task no. 4.2.2.

Project Partners:

• German Aerospace Center (DLR), Institute of Aeroelastics, Göttingen, Germany
• Nordex Energy GmbH, Hamburg, Germany
• Senvion GmbH, Hamburg, Germany