SIROCCO: Silent Rotors by Acoustical OptimizationAnsprechpartner: Dr.-Ing. Thorsten Lutz, Dr.-Ing. Andreas Herrig, Dr.-Ing. Werner Wuerz
Project Information & ChallengesSIROCCO was a European project that ran from 2003 to 2005. Despite the fast acceleration of wind energy implementation, wind turbine noise is still one of the major hindrances for the widespread use of wind energy in Europe. For modern large turbines, aerodynamic (in particular trailing edge) noise is considered to be the dominant noise source. In a number of European and national projects in the last decade, the understanding of aerodynamic noise from wind turbines has increased significantly, and new noise reduction concepts have been developed. In the recent EU project DATA ('Design and Testing of Acoustically Optimised Airfoils for Wind Turbines') these concepts resulted in a noise reduction of 3-6 dB on a model scale wind turbine in a large wind tunnel. Such a noise reduction offers enormous potentials, not only with respect to noise regulations, but also in terms of e.g. a smaller distance to the nearest building, an increased tip speed, or increased public acceptance. In this way, the implementation of wind energy in Europe can be increased greatly. Furthermore, silent rotors will improve the position of the European Wind Turbine Industry with respect to its competitors. Therefore, the objective of SIROCCO is to obtain a noise reduction of 3-6 dB on full-scale wind turbines, without a reduction in power performance.
In order to achieve this goal, the project will start with acoustic field measurements to characterise the noise sources on two existing (baseline) wind turbines. A new measurement technique, developed in DATA, will be extended and utilised to localise and quantify noise sources on the rotating blades. Parallel to the field measurements, a combined acoustic/ aerodynamic design methodology that was developed in DATA will be extended to design low-noise airfoils. Airfoils shall be developed, which in contrast to the DATA project exhibit this noise reduction in the polluted (rough) state, the normal one for a wind turbine under real-world conditions. Subsequently the new airfoils will be tested in small scale, two-dimensional acoustic and aerodynamic wind tunnel tests. If the results are satisfactory, low-noise blades will be designed. These desings will be assessed analytically and if the outlook is promising, the blades will be manufactured to validate the acoustic and aerodynamic performance on full-scale wind turbines.
Objectives of IAGThe idea of the SIROCCO project is to reduce flow-induced noise source by the design and direct numerical optimization of dedicated low-noise airfoil sections. For this design task an efficient but reliable and consistent aerodynamic and aeroacoustic airfoil analysis method was developed on the basis of models derived within previous European research projects. Extensive validation by comparison to detailed boundary-layer experiments and acoustic measurements conducted in the LaminarWind Tunnel (LWT) of the IAG.
- A validated design methodology for silent airfoils on wind turbine blades (IAG)
- A validated noise prediction code for wind turbines (ECN)
- Measurement technique to localise and quantify the noise sources on wind turbine blades (NLR)
- Silent wind turbine blades for turbine 1 (Gamesa)
- Silent wind turbine blades for turbine 2 (GE Energy)
Work package partners
- National Aerospace Laboratory, NLR (NL)
- Institute of Aerodynamics & Gas Dynamics (IAG),University of Stuttgart USTUTT (FRG)
- Gamesa Eólica S.A. (E)
- Composite Technology Centre CTC (NL)
- NOI Rotortechnik GmbH (FRG)
- Project Website: www.ecn.nl/nl/units/wind/projecten/sirocco
Sources: SIROCCO Project Website, CORDIS, Research & Innovation in Baden-Wuerttemberg