Molecular dynamics simulation of surface roughness effects on nanoscale flows

In the present study, a molecular based scheme has been developed for simulating of surface roughness effects on nano- and micro-scale flows. In micro channel flow, there are some differences on the flow friction between roughness and cavitations which are not well studied. In the presented approach, based on the Molecular Dynamics Simulation (MD), the Lennard-Jones potential is used to model the interactions between particles. Particles equation of motion is integrated using fifth order Gear predictor-corrector. Periodic boundary condition is implemented via minimum image convention. Each atom of the solid wall is anchored at its lattice site by a harmonic restoring force and its temperature has been controlled by utilizing Nose-Hoover thermostat. The roughness is implemented on the lower channel wall. To make a comparison between the effect of roughness and cavitations, the same dimension is used for both with different aspect ratio. To allow comparison with previous results, the same fluid density has been also used. The effects of surface roughness and cavitations on velocity distribution of hydrophobic and hydrophilic wall undergoing Poiseuille flow are presented. (C) 2010 Elsevier Masson SAS. All rights reserved.