Sub-scaling method is capable of representing full-scale wind turbine dynamics
The wind power industry is expected to grow in the coming years as interests in renewable energy sources continue to rise. In order to capture more wind energy, turbine sizes have been growing as well. New designs suggest the use of blades greater than 100 meters in length, well above the conventional size used for wind turbines.
“The increase in blade lengths leads to highly flexible blades which were once described to me as ‘wet noodles’,” said Meghan Kaminski, an author on a paper developing a turbine sub-scaling method. “A full-scale model to test the practicality of the highly flexible blades would be grossly expensive.”
For more cost-effective testing, the researchers created and tested small-scale models which operate like the full-scale blades. They applied their method, called Servo-Aero-Gravo-Elastic Scaling, to create a 20 percent scale model of a 13-MW turbine. They found they were able to keep the blade dynamics of the 20 percent model similar to its full-size counterpart.
Kaminski says this shows a sub-scale model is capable of representing the full-scale turbine.
“Since this scaling is applied to extreme-scale blades, the flexibility and gravitational loads of the structure are highly important,” she said. ‘The modelling of the wind turbine u sed puts these at the forefront of the scaling methodology in order to better match the full-scale dynamics during operation. “
In the future, the method could be applied to test other full-scale systems at a fraction of the cost.
“I am hoping this type of scaling will be able to be used for any type of aeroelastic modelling as we move forward with renewable energy projects,” said Kaminski.
Source: “Servo-Aero-Gravo-Elastic (SAGE) scaling and its application to a 13-MW downwind turbine,” by Meghan Kaminski, Eric Loth, Daniel Zalkind, Lucy Pao, Michael Selig, and Kathryn Johnson, Journal of Renewable and Sustainable Energy (2020). The article can be accessed at https://doi.org/10.1063/5.0021171 .