Parametric study of particle sedimentation by dissipative particle dynamics simulation.

A parametric study on the simulation of a single aluminum (Al) particle settling in water is conducted using various sets of interactive parameters between Al and water particles, so that a systematic method can be established to describe the hydrodynamic interaction between an Al particle and the fluid in a large range of particle sizes. The force parameters and the cutoff have been correlated to the terminal settling velocity of the Al particle in the dissipative particle dynamics simulation, so that the classic Stokes' law can be used to determine those parameters. Two empirical equations are developed to calculate the minimum repulsive force parameter in terms of the number density and radius, respectively. In addition, the correlation between the cutoff and the Al particle radius has been obtained by linear curve fitting. The radial distribution functions of Al and water particles are computed to examine the relative spacing among solid and fluid particles. The present approach is general and can also be extended to study particle motion of other types of particles and fluids. This study will be a baseline for the investigation of multiple particles settling in a viscous fluid.