We present a novel continuum-based model that enables efficient
simulation of granular materials. Our approach fully solves the internal
pressure and frictional stresses in a granular material, thereby
allows visually noticeable behaviors of granular materials to be reproduced,
including freely dispersing splashes without cohesion,
and a global coupling between friction and pressure. The full treatment
of internal forces in the material also enables two-way interaction
with solid bodies. Our method achieves these results at
only a very small fraction of computational costs of the comparable
particle-based models for granular flows.