Transport coefficients of dissipative particle dynamics with finite time step

The viscosity and self-diffusion constant of a mesoscale hydrodynamic method, dissipative particle dynamics (DPD), are investigated. The viscosity of DPD with finite time step, including the Lowe-Anderson thermostat, is derived analytically for the ideal-gas equation of state and phenomenologically for systems with soft repulsive potentials. The results agree well with numerical data. A velocity-scaling version of the profile-unbiased thermostat is shown to be useful to obtain faster diffusion than for the DPD thermostat.