Mesoscopic Multi-particle Collision Model for Fluid Flow and Molecular Dynamics

Abstract

Several aspects of modeling dynamics at the mesoscale level are discussed: (1) The construction of a mesoscopic description of fluid dynamics. The mesoscale dynamics consists of free streaming interrupted by multi-particle collisions. The multi-particle collisions are carried out by performing random rotations of particle velocities in predetermined cells in a manner that conserves mass, momentum and energy. The algorithmic implementation of the method is described and its theoretical basis is justified. Examples of simulation results on hydrodynamic flows are presented. (2) A hybrid molecular dynamics (MD)-Mesoscale Solvent model is described next. In this method full MD of solute particles is combined with the mesoscale dynamics of the surrounding fluid. The method is illustrated by considering the diffusive dynamics and hydrodynamic interactions among solute particles and clusters in the mesoscale solvent. (3) Finally, extensions of such schemes are outlined. In particular, generalizations to molecular solvents are presented and examples of solute dynamics in mesoscale water are given; also extensions to reactive flows are described.