Simulation of vapor-liquid coexistence using dissipative particle dynamics

Due to a purely repulsive conservative interaction adopted in the traditional dissipative particle dynamics, the vapor-liquid coexistence phenomena or fluid flows with free surfaces could not be simulated. In the present study a recently proposed combination of short-range repulsive and long-range attractive interaction for DPD was investigated to explore its ability of simulating vapor-liquid coexistence or fluid flows with free surfaces. With this modified interaction, steady vapor-liquid interface could be obtained in DPD simulation, and the stress distribution across the vapor-liquid interface region was also discussed, which were found in accordance with those obtained by multibody DPD. Furthermore, surface tension of vapor-liquid interface was studied, and it was verified that Laplace' s law is satisfied in our simulation. Surface tensions obtained by theoretical method and Laplace' s law, respectively, are in agreement with each other.