The heart of the question is with regard to details of implementing
SIMPLE shear boundary conditions in  continuum models, specifically
for granular systems.

I am looking for any details regarding the implementation of
Lees-Edwards type boundary conditions in a granular continuum model. 
Such boundary conditions produce a system with SIMPLE shear by
implementing moving periodic boundary conditions.  These moving
periodic boundaries (in the case of granular systems) result in
significantly different dynamics than other sheared systems, i.e,
Couette Flow.

In the least, I would like to get an idea of the viability and ease of
such implementation and perhaps some links to information such that I
can ultimately resolve the details of my own implementation.  An
explicit answer (while certainly desirable) is not necessary.  I just
need some good leads.