Viscous dissipation effect in nano-confined shear flows: a comparative study between molecular dynamics and multi-scale hybrid simulations

Abstract

In this work, a full molecular dynamics simula- tion (MDS) of nano-confined shear flows has been conducted to examine the effect of viscous dissipation and applicability of multi-scale hybrid simulation. In the cases of high shear rate and strong solid-liquid interaction, the difference is clearly seen between the MDS and hybrid simulation results. The applicability of the hybrid simulation is found highly dependent on the effect of viscous dissipation. The non- monotonic variation of the average temperature found in pressure-driven flows is also found in the present shear-driven flows. By comparatively analyzing the molecular dynamics and hybrid simulation results, it is confirmed that the hybrid simulation is valid and the explicit correlation between the slip and Kapitza lengths is valid in the ranges of shear rate ( _ c ¼ 0:012� 0:094 s � 1 , s being the time scale) and solid- liquid interaction factor (b = 0.1-10). Although the hybrid simulation results deviate from the MDS results due to the effect of viscous dissipation, the explicit correlation between the slip and Kapitza lengths still holds.