Print Email Facebook Twitter Wind turbine wake stability investigations using a vortex ring modelling approach Title Wind turbine wake stability investigations using a vortex ring modelling approach Author Baldacchino, D. Van Bussel, G.J.W. Faculty Aerospace Engineering Department Aerodynamics, Wind Energy & Propulsion Date 2014-12-31 Abstract In the present study, a simple inviscid vortex ring (VR) modelling approach is used to represent the developing rotor wake. This allows a straightforward investigation and comparison of the impact of uniform, yawed and sheared flow conditions on the development of the rotor wake, with the additional possibility of including ground effect. The effect of instabilities on the development of the wake is manually introduced in the form of perturbations of strength, ring position and size. The phenomenon of vortex filament interaction or leapfrogging, could play a role in the observation of unsteady phenomena and is therefore also addressed. Such a study is hence performed in light of recent conflicting views on the causes of wake meandering: is the observed dynamic wake behaviour a result of large scale turbulent forcing or do more subtle and intrinsic wake instabilities play a role? This study concludes that the presence of the ground and external perturbations, most notably changes in the wake pitch and the rotor thrust coefficient, can significantly affect the steady development of the wake. The mutual vortex pairing instability, whilst displaying interesting periodic behaviour, does not correlate with periodic wake behaviour reported by Medici et al. [1]. However, in the absence of unsteady inflow, it is shown that the wake of a Horizontal Axis Wind Turbine (HAWT) is certainly prone to displaying unstable, dynamic behaviour caused by these additional factors. To reference this document use: http://resolver.tudelft.nl/uuid:c948d7c3-1cb8-41a2-a658-709815786195 Publisher IOP Publishing ISSN 1742-6588 Source Journal of Physics: Conference Series, 555 (2014), 012111 Part of collection Institutional Repository Document type journal article Rights (c) CC BYContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd Files PDF 1742-6596_555_1_012111.pdf 1.1 MB Close viewer /islandora/object/uuid:c948d7c3-1cb8-41a2-a658-709815786195/datastream/OBJ/view