A Study on Slip Characteristics Using Hybrid Particle-Continuum Method

Abstract

An effective boundary potential has been proposed to solve nonperiodic boundary condition (NPBC) of hybrid method. The optimized hybrid method is applied to investigate the influences of the channel height and solid–liquid interaction parameters on slip characteristics of Couette flows in micro/nanochannels. By changing the channel height, we find that the relative slip lengths show the obvious negative correlation with the channel height and fewer density oscillations are generated near the solid wall in the larger channel height. Moreover, we continue to investigate the solid–liquid interaction parameters, including the solid–liquid energy scales ratio (C1) and solid–liquid length scales ratio (C2). The results show that the solid–liquid surface changes from hydrophobic to hydrophilic with the increase of C1, the arrangement of liquid particles adjacent to the solid particles is more disorganized over the hydrophobic solid–liquid surface compared with the hydrophilic surface, and the probability of the liquid particles that appear near the solid particles becomes smaller. Meanwhile, the relative slip lengths are minimum when the liquid and solid particles have the same diameter. Furthermore, the relative slip lengths follow a linear relationship with the shear rate when the solid–liquid interaction parameters change. The plenty computational time has been saved by the present hybrid method compared with the full molecular dynamics simulation (FMD) in this paper.