Micro-hydrodynamics

Micro-hydrodynamics is a term used to describe the search for and study of hydrodynamic phenomena at microscopic scales. The principal method used to accomplish this research is molecular dynamic (MD) simulations. Computational limits on MD models restrict the size of the system and simulation time. Typically, the length scales are on the order of 10–1000 Å and time scales 10–1000 psec (thus the qualifier micro). We review the results of our research in this area. We use MD to model channel flow, flow past a plate, flow past a cylinder, and Rayleigh-Benard convection. In general, we find that the behavior in these models agrees with results obtained from experiment and more traditional theoretical approaches, such as solving the Navier-Stokes equations. In addition to the appearance of spatial and temporal patterns, we observe scaling relations in agreement with those predicted by macroscopic hydrodynamics. In some specific situations, we can see the breakdown of Navier-Stokes theory and estimate its limits.