Wind turbine near wakes and comparisons to the wake behind a disc
2005 (English)Conference paper (Refereed)
The wake development behind wind turbines affects power losses in turbine parks aswell as the flow induced rotor loads due to wake turbulence. In the near wake region tipvortices are a distinct feature of the flow. Such vortices do not exist behind a circulardisc but instead the flow is characterized by a large scale vortex shedding. In our windtunnel experiments we have observed similar large scale vortex shedding in the wake of atwo-bladed wind turbine model. The frequency of the shedding in terms of the Strouhalnumber decreases with increasing tip speed ratio and levels out at a value which is close tothat observed for a solid disc. For low tip speed ratios no large scale vortex shedding wasobserved. When the turbine was yawed the shedding frequency increased in a similar wayas for an inclined disc. In order to further investigate this phenomenon we have studiedthe vortex shedding behind solid and porous discs. All our results indicate that a turbineat high tip speed ratio sheds large scale structures in a similar way as a disc. We alsohypothesize that the vortex shedding is the cause for the observed meandering of wakeswhich has been observed behind full scale turbines.
Place, publisher, year, edition, pages
2005. 15593-15604 p.
Fluid Mechanics and Acoustics
IdentifiersURN: urn:nbn:se:kth:diva-9025ScopusID: 2-s2.0-30744452472OAI: oai:DiVA.org:kth-9025DiVA: diva2:14561
43rd AIAA Aerospace Sciences Meeting and Exhibit, 10-13 January 2005, Reno, Nevada, USA
QC 201412042006-01-262006-01-262014-12-04Bibliographically approved