Fluid Particle Models for the Simulation of Microfluids

Abstract

In the present work, some of the mesoscopic particle methods generally used for the simulation of microstructured fluids are reviewed. In particular, the Dissipative Particle Dynamics (DPD) method, designed by Hoogerbrugge and Koelman in 1992, offers a good compromise of performance and flexibility. Some aspects of the method are discussed as well as the main conceptual shortcomings which limit its current applicability to some micro-flow conditions. Refined models of DPD are therefore presented, i.e. Smoothed Dissipative Particle Dynamics (SDPD) (Espanol and Revenga, Phys. Rev. E 67:026705, 2003). The method is a thermodynamically consistent version of DPD and, at the same time represents a direct discretization of the continuous Navier-Stokes equations on a Lagrangian framework. This feature is common to another macroscopic particle method, i.e. Smoothed Particle Hydrodynamics (SPH) (Gingold and Monaghan, Mon. Not. R. Astron. Soc. 181:375, 1977). SDPD can be therefore understood as a mesoscopic version of SPH with thermal fluctuations consistently included and provides the unifying multiscale framework linking DPD to SPH. Finally, applications of the model to microfluids are discussed. In particular, results for polymer molecules and colloidal particles suspended in Newtonian solvent are presented.