Abstract
The actuator line method made it possible to describe the near wake of a wind turbine more accurately than with the actuator disk method. Whereas the actuator line generates the helicoidal vortex system shed from the tip blades, the actuator disk method sheds a vortex sheet from the edge of the rotor plane. But with the actuator line come also temporal and spatial constraints, such as the need for a much smaller time step than with actuator disk. While the latter one only has to obey the Courant-Friedrichs-Lewy condition, the former one is also restricted by the grid resolution and the rotor tip-speed. Additionally the spatial resolution has to be finer for the actuator line than with the actuator disk, for well resolving the tip vortices. Therefore this work is dedicated to examining a method in between of actuator line and actuator disk, which is able to model the transient behaviour, such as the rotating blades, but which also relaxes the temporal constraint. Therefore a larger time-step is used and the blade forces are swept over a certain area. The main focus of this article is on the aspect of the blade tip vortex generation in comparison with the standard actuator line and actuator disk.
Original language | American English |
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Article number | Article No. 01001 |
Number of pages | 8 |
Journal | E3S Web of Conferences |
Volume | 5 |
DOIs | |
State | Published - 16 Oct 2015 |
Event | 2nd Symposium on OpenFOAM in Wind Energy, SOWE 2014 - Boulder, United States Duration: 19 May 2015 → 21 May 2015 |
Bibliographical note
Publisher Copyright:© 2015 Owned by the authors, published by EDP Sciences.
NREL Publication Number
- NREL/JA-5000-68400
Keywords
- actuator line method
- blade tip vortex generation
- wind turbines