CORDIS provides links to public deliverables and publications of HORIZON projects.
Links to deliverables and publications from FP7 projects, as well as links to some specific result types such as dataset and software, are dynamically retrieved from OpenAIRE .
Deliverables
The aim of the STENO project was to investigate the reduction of the aerodynamic noise of a wind turbine by applying serrations (saw teeth) at the trailing edge of the outer part of a blade. At the beginning of the project it was known from wind tunnel experiments performed on two-dimensional (generic) models of wind turbine blades, that serrated trailing edges have the potential to reduce boundary-layer trailing-edge (TB-TE or just for short TE) noise by 3-6 dB. TE noise is known to be the most important contributor to the overall (A-weighted) noise level of modern, large wind turbines. To obtain these reductions on a real turbine, it was expected that the shape, orientation and spreading of the serrations had to be optimised as a function of the characteristics of the boundary layer along the rotating blade.
A prediction model developed by TNO/TPD in the parallel JOULE project DRAW [34] was used and extended to the case where the trailing edge is serrated. The prediction models have been developed and validated using the results of a series of wind tunnel experiments. These experiments were carried out on various models of blade tips in the 2.25x3 m(2) closed test section of the Low Speed Wind Tunnel (LST) of the German Dutch Wind Tunnel (DNW) and the 0.4x0.5 m2 anechoic wind tunnel (KAT) of the National Aerospace Laboratory (NLR).
The prediction model has been used to define saw-teeth geometries, which have been manufactured and mounted on the outer part of one blade of the UNIWEX test turbine of the University of Stuttgart. The measurements of the noise radiated from this blade and of the (untreated) reference blade were carried out using an acoustic parabola. The analyses of both the UNIWEX and the wind tunnel results have led to the insight that the way the serrations had always been applied during previous (wind tunnel) tests and a (Dutch national) test on a 1 MW turbine is not optimal, i.e. the application of serrations should be applied in such a way that the distortion of the flow streamlines is minimized. If the teeth are applied in this way on a blade of the UNIWEX turbine a noise reduction of 2-3.5 dB is obtained at all frequencies of interest.
With the help of the prediction models developed, the proved noise-reduction capabilities of serrations can be translated into practical guidelines for their optimal application. These guidelines can be followed by blade manufacturers.
Searching for OpenAIRE data...
There was an error trying to search data from OpenAIRE
No results available