  The simulation of granular media is usually done either with event-driven
codes that treat collisions as instantaneous but have difficulty with very
dense packings, or with molecular dynamics methods that approximate rigid
grains using a stiff viscoelastic spring. There is a little-known method that
combines several collision events into a single timestep in order to retain the
instantaneous collisions of event-driven dynamics but also be able to handle
dense packings. However, it is poorly characterized as to its regime of
validity and failure modes. We present a modification of this method to reduce
the introduction of overlap error, and test it using the problem of 2D granular
Couette flow, a densely packed system that has been well-characterized by
previous work. We find that this method can successfully replicate the results
of previous work up to the point of jamming, and that it can do so a factor of
10 faster than comparable MD methods.
