Abstract. This paper presents an investigation of wakes behind model wind turbines,
including cases of yaw misalignment. Two different turbines were used and
their wakes are compared, isolating effects of boundary conditions and
turbine specifications. Laser Doppler anemometry was used to scan full planes
of wakes normal to the main flow direction, six rotor diameters downstream of
the respective turbine. The wakes of both turbines are compared in terms of
the time-averaged main flow component, the turbulent kinetic energy and the
distribution of velocity increments. The shape of the velocity increments'
distributions is quantified by the shape parameter λ2. The results
show that areas of strongly heavy-tailed distributed velocity increments
surround the velocity deficits in all cases examined. Thus, a wake is
significantly wider when two-point statistics are included as opposed to a
description limited to one-point quantities. As non-Gaussian distributions of
velocity increments affect loads of downstream rotors, our findings impact
the application of active wake steering through yaw misalignment as well as
wind farm layout optimizations and should therefore be considered in future
wake studies, wind farm layout and farm control approaches. Further, the
velocity deficits behind both turbines are deformed to a kidney-like curled
shape during yaw misalignment, for which parameterization methods are
introduced. Moreover, the lateral wake deflection during yaw misalignment is
investigated.