  Modelling of turbine blade-induced turbulence (BIT) is discussed within the
framework of three-dimensional Reynolds-averaged Navier-Stokes (RANS) actuator
disk computations. We first propose a generic (baseline) BIT model, which is
applied only to the actuator disk surface, does not include any model
coefficients (other than those used in the original RANS turbulence model) and
is expected to be valid in the limiting case where BIT is fully isotropic and
in energy equilibrium. The baseline model is then combined with correction
functions applied to the region behind the disk to account for the effect of
rotor tip vortices causing a mismatch of Reynolds shear stress between short-
and long-time averaged flow fields. Results are compared with wake measurements
of a two-bladed wind turbine model of Medici and Alfredsson [Wind Energy, Vol.
9, 2006, pp. 219-236] to demonstrate the capability of the new model.
