  Direct numerical simulations (DNS) are performed to study the turbulent shear
flow of an electrically conducting fluid in a cylindrical container. The flow
is driven by the interaction between the radial electric currents ($I$)
injected through a large number of small electrodes at the bottom wall and an
axial magnetic field. All the numerical parameters, including the geometry of
the container, the total injcected currents and the magnetic field, are in line
with the experiment performed in J. Fluid Mech. 456, 137-159. First, witth
laminar Hartmann layers, three dimensional simulations recover experimentally
measured quantities (global angular momentum, velocity profiles). The variation
laws for the wall shear stresses, the energy spectra and visualizations of flow
structures near the side wall highlight separation and turbulence within the
side wall layers. Furthermore, a parametric analysis of the flow reveals that
Ekman recirculations have significant influence on the vortex size, the free
shear layer, and the global dissipation. Second, we recover the scaling laws of
the cutoff scale that separate the large quasi-two-dimensional scales from the
small three-dimensional ones (J. Fluid Mech. 118, 507-518), and thus establish
their validity in sheared MHD turbulence. Furthermore, we find that
three-componentality are and the three-dimensionality appear concurrently and
that both the two-dimensional cutoff frequency and the mean energy associated
to the axial component of velocity scale with $N_t$, respectively as
$0.063N_t^{0.37}$ and $0.126 N_t^{-0.92}$.
