  The von Karman flow apparatus produces a highly turbulent flow inside a
cylinder vessel driven by two counter-rotating impellers. Over more than two
decades, this experiment has become a very classic turbulence tool, studied for
a wide range of physical systems by many groups, with incompressible flow,
compressible flow, for magnetohydrodynamics and dynamo studies inside liquid
metal, for particle tracking purposes, and recently with turbulent super-fluid
helium. We present a direct numerical simulation (DNS) version the von Karman
flow, forced by two rotating impellers. The cylinder geometry and the rotating
objects are modelled via a penalization method and implemented in a massive
parallel pseudo-spectral Navier-Stokes solver. We choose a special
configuration (TM28) of the impellers to be able to compare with set of water
experiments well documented. But our good comparison results implied, that our
numerical modelling could also be applied to many physical systems and
configurations driven by the von Karman flow. The decomposition into poloidal,
toroidal components and the mean velocity fields from our simulations are in
agreement with experimental results. We analyzed also the flow structure close
to the impeller blades and found different vortex topologies.
