Wake evolution and trailing vortex instabilities
2011 (English)Conference paper (Other academic)
The production losses and inhomogeneous loads of wind powerturbines placed in the wake of another turbine is a well-known problemwhen building new wind power farms, and a subject of intensive research.The present work aims at developing an increased understanding of thebehaviour of turbine wakes, with special regard to wake evolution andthe stability of the trailing vortices. Single point velocity measurementswith hot-wire anemometry were performed in the wake of a small-scalemodel turbine. The model was placed in the middle of the wind tunneltest section, outside the boundary layers from the wind tunnel walls.In order to study the stability of the wake and the trailing vortices,a disturbance was introduced at the end of the nacelle. This was ac-complished through two ori¯ces perpendicular to the main °ow, whichwere connected to a high-pressure tank and two fast-switching valves.Both varicose and sinusoidal modes of di®erent frequencies could be trig-gered. By also triggering the measurements on the blade passage, themeandering of the wake and the disturbance frequency, phase averagedresults could be computed. The results for di®erent frequencies as wellas studies of wake evolution will be presented.
Place, publisher, year, edition, pages
Other Engineering and Technologies not elsewhere specified
IdentifiersURN: urn:nbn:se:kth:diva-85924OAI: oai:DiVA.org:kth-85924DiVA: diva2:500200
American Physical Society, 64th Annual meeting of the APS Div. Fluid Dyn., Nov. 20-22, Baltimore, Maryland
QC 201204102012-02-132012-02-132012-04-10Bibliographically approved