Support structure modelling in actuator line method large eddy
simulations of wind turbine wakes
Abstract
While advancements in the prediction of wind turbine loads and wakes
within the actuator line method large eddy simulation (ALM-LES)
framework have been an active research topic in recent years, the
modelling of the tower and nacelle has received comparatively less
attention. This paper investigates different numerical modelling methods
for the representation of the support structure and discusses the
implications and trade offs associated with each method. Three support
structure modelling approaches are investigated: explicitly meshing the
support structure; a direct forcing meshless representation; and a
combination of actuator disc/line method for the representation of the
nacelle/tower. All methods contribute to a more realistic representation
of the near wake mean flow when compared to experimental measurements.
In the measured far wake, the interaction between the tower and rotor
wakes creates asymmetries in the mean flow profiles. The meshed and
cell-blocking numerical representations are capable of replicating these
far wake asymmetries. In contrast, the actuator method has a less
pronounced effect on the far wake mean flow.