  Large Eddy Simulations (LES) are used to study the effects of veer (the
height-dependent lateral deflection of wind velocity due to Coriolis
acceleration) on the evolution of wind turbine wakes. Specifically, this work
focuses on turbines that are yawed with respect to the mean incoming wind
velocity, which produces laterally deflected wakes that have a curled
(crescent-shaped) structure. These effects can be attributed to the
introduction of streamwise mean vorticity and the formation of a
Counter-rotating Vortex Pair (CVP) on the top and bottom of the wake. In a
Truly Neutral Boundary Layer (TNBL) in which wind veer effects are absent,
these effects can be captured well with existing analytical wake models
(Bastankhah et al. J. Fluid Mech. (2022), 933, A2). However, in the more
realistic case of atmospheric boundary layers subjected to Coriolis
acceleration, existing models need to be re-examined and generalized to include
the effects of wind veer. To this end, the flow in a Conventionally Neutral
Atmospheric Boundary Layer (CNBL) interacting with a yawed wind turbine is
investigated in this study. Results indicate that in the presence of veer the
CVP's top and bottom vortices exhibit considerable asymmetry. However, upon
removing the veer component of vorticity, the resulting distribution is much
more symmetric and agrees well with that observed in a TNBL. These results are
used to develop a simple correction to predict the mean velocity distribution
in the wake of a yawing turbine in a CNBL using analytical models. The
correction includes the veer-induced sideways wake deformation, as proposed by
Abkar et al. (Energies (2018), 11(7), 1838). The resulting model predictions
are compared to mean velocity distributions from the LES and good agreement is
obtained.
