  Coupled models are set to become increasingly important in all aspects of
science and engineering as tools with which to study complex systems in an
integrated manner. Such coupled, hybrid simulations typically communicate data
between the component models of which they are comprised relatively
infrequently, and so a Grid is expected to present an ideal architecture on
which to run them. In the present paper, we describe a simple, flexible and
extensible architecture for a two-component hybrid molecular-continuum coupled
model (hybrid MD). We discuss its deployment on distributed resources and the
extensions to the RealityGrid computational-steering system to handle coupled
models.
