Modeling of dense suspensions,
present some issues related to the numerical modeling of dense
suspensions of rigid bodies in a viscous fluid, for which close
range lubrication forces may play a significant role.
In the context
of direct numerical simulations, thoses forces are supposed to be
accounted for in the equations for the fluid. Yet, as interparticle
distances may be very small compared to other characteristic lengths,
most solvers are likely to fail in giving an accurate description of
the interstitial flow.
For this reason, different approaches have
been proposed, and we will describe some of them in terms of
numerical efficiency, respect of the underlying physics, and
influence upon the global behaviour of the suspension.