Flow of multiparticle collision dynamics fluids confined by physical barriers

Abstract

We propose a new method for confining of fluids simulated by Multiparticle Collision Dynamics. In this method confinement is achieved by introducing solid surfaces consisting of particles that interact with the particles of the fluid by means of explicit repulsive forces. We derive an integrated expression for the interaction potential between the fluid and the solid wall in which the molecular properties of the latter are averaged and reduced to an equation that involves only its geometrical features. We test the applicability of the proposed model in simulations of fluids confined between two parallel planes and subjected to a uniform force field. We find that our model yields the correct plane Poiseuille flow expected from hydrodynamics with slip boundary conditions. We carry out an extensive numerical analysis of the method for a wide range of values of the simulation parameters. We measure important quantities characterizing the flow and the fluid-solid interaction, e.g., the slip at the solid boundary and the effective viscosity of the fluid. Finally, we determine the conditions for which flows with stick boundary condition can be simulated.