International Journal of Thermophysics, Vol. 7, No. 3, 1986 Rheology and Thermodynamics from Nonequilibrium Molecular Dynamics t Denis J. Evans 2 We review some of the recent developments in nonequilibrium molecular dynamics (NEMD) simulations of fluids. One of the areas which has been profoundly influenced by this new technique is the study of systems undergoing steady planar Couette flow. Attention has been focused on developments which have taken place since the 1982 Conference on Nonlinear Fluid Behaviour. Since that time many questions concerning the formal justification of NEMD algorithms have been successfully answered. There have also been extensions of the range of properties studied by the technique. KEY WORDS: algorithms; Couette flow; nonequilibrium molecular dynamics; nonlinear fluid behavior; rheology; simulation. 1. INTRODUCTION In this review, we concentrate on developments that have taken place since the 1982 Conference on Nonlinear Fluid Behavior El]. At that time, NEMD simulations of planar Couette flow had revealed that even simple atomic fluids can, under suitable conditions, exhibit a wide variety of non- Newtonian behavior. The Lennard-Jones fluid had been shown to be viscoelastic, shear thinning, and capable of displaying normal stress effects [2]. All of these properties are well-known, experimentally observable effects in molecularly complex non-Newtonian fluids. The simulations also revealed an associated property which is almost impossible to observe experimentally, namely, shear dilatancy--the expansion of fluids with increasing shear rate under isothermal isobaric conditions. Before the t Invited paper presented at the Ninth Symposium on Thermophysical Properties, June 24-27, 1985, Boulder, Colorado, U.S.A. 2 Research School of Chemistry, Australian National University, GPO Box 4, Canberra A.C.T. 2601, Australia. 573 0195-928X/86/0500-0573505.00/09 1986 Plenum Publishing Corporation