  A three-dimensional (3D) direct numerical simulation is combined with a
laboratory study to describe the turbulent flow in an enclosed annular
rotor-stator cavity characterized by a large aspect ratio G=(b-a)/h=18.32 and a
small radius ratio a/b=0.152, where a and b are the inner and outer radii of
the rotating disk and h is the interdisk spacing. The rotation rate Omega under
consideration is equivalent to the rotational Reynolds number Re=Omegab2/nu=9.5
x 104, where nu is the kinematic viscosity of the fluid. This corresponds to a
value at which an experiment carried out at the laboratory has shown that the
stator boundary layer is turbulent, whereas the rotor boundary layer is still
laminar. Comparisons of the 3D computed solution with velocity measurements
have given good agreement for the mean and turbulent fields. The results
enhance evidence of weak turbulence at this Reynolds number, by comparing the
turbulence properties with available data in the literature. An approximately
self-similar boundary layer behavior is observed along the stator side. The
reduction of the structural parameter a1 under the typical value 0.15 and the
variation in the wall-normal direction of the different characteristic angles
show that this boundary layer is three-dimensional. A quadrant analysis of
conditionally averaged velocities is performed to identify the contributions of
different events (ejections and sweeps) on the Reynolds shear stress producing
vortical structures. The asymmetries observed in the conditionally averaged
quadrant analysis are dominated by Reynolds stress-producing events in this
B\"{o}dewadt layer. Moreover, case 1 vortices (with a positive wall induced
velocity) are found to be the major source of generation of special strong
events, in agreement with the conclusions of Lygren and Andersson.
