Smoothed Dissipative Particle Dynamics model for mesoscopic multiphase flows in the presence of thermal fluctuations

TL;DR

This paper introduces a novel multiphase smoothed dissipative particle dynamics model that incorporates thermal fluctuations, accurately capturing interfacial phenomena and hydrodynamics in multiphase flows across various temperatures.

Contribution

The work develops a new SDPD model that accounts for thermal fluctuations and relates model parameters to surface tension over a wide temperature range.

Findings

Model accurately captures bubble coalescence and capillary spectra.

Relationship between parameters and surface tension is validated for different thermal fluctuations.

The model extends previous zero-fluctuation assumptions to finite temperature regimes.

Abstract

Thermal fluctuations cause perturbations of fluid-fluid interfaces and highly nonlinear hydrodynamics in multiphase flows. In this work, we develop a novel multiphase smoothed dissipative particle dynamics model. This model accounts for both bulk hydrodynamics and interfacial fluctuations. Interfacial surface tension is modeled by imposing a pairwise force between SDPD particles. We show that the relationship between the model parameters and surface tension, previously derived under the assumption of zero thermal fluctuation, is accurate for fluid systems at low temperature but overestimates the surface tension for intermediate and large thermal fluctuations. To analyze the effect of thermal fluctuations on surface tension, we construct a coarse-grained Euler lattice model based on the mean field theory and derive a semi-analytical formula to directly relate the surface tension to model parameters for a wide range of temperatures and model resolutions. We demonstrate that the present method correctly models the dynamic processes, such as bubble coalescence and capillary spectra across the interface.