No-slip boundary condition in dissipative particle dynamics

Dissipative Particle Dynamics (DPD) has, with only a few exceptions, been u sed to study hydrodynamic behavior of complex fluids without confinement. P revious studies used a periodic boundary condition, and only bulk behavior can be studied effectively. However, if solid walls play an important role in the problem to be studied, a no-slip boundary condition in DPD is requir ed. Until now the methods used to impose a solid wall consisted of a frozen layer of particles. If the wall density is equal to the density of the sim ulated domain, slip phenomena are observed. To suppress this slip, the dens ity of the wall has to be increased. We introduce a new method, which intri nsically imposes the noslip boundary condition without the need to artifici ally increase the density in the wall. The method is tested in both a stead y-state and an instationary calculation. If repulsion is applied in frozen particle methods, density distortions are observed. We propose a method to avoid these distortions. Finally, this method is tested against conventiona l computational fluid dynamics (CFD) calculations for the flow in a lid-dri ven cavity. Excellent agreement between the two methods is found.