Computer simulation of irreversible expansions via molecular dynamics, smooth particle applied mechanics, Eulerian, and Lagrangian continuum mechanics

We simulate the far-from-equilibrium irreversible expansion or a compressed ideal gas in two space dimensions. For this problem the particle trajector ies from conventional smooth particle applied mechanics are isomorphic to t hose from a corresponding molecular dynamics simulation. The smooth-particl e "weight function" used to describe the expanding gas is identical to the pair potential governing the molecular dynamics simulation. These many-body particle simulations are compared with those using a modified smooth-parti cle algorithm invented by Monaghan, as well as with those based on conventi onal grid-bused Eulerian and Lagrangian methods.