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. The scaling of the local relative velocity in molecular dynamics simulations is shown to be useful to obtain faster diffusion than for the DPD thermostat.