Velocity Inversion in Nanochannel Flow

TL;DR

This study uses molecular dynamics simulations to explore velocity inversion phenomena in nanoscale cylindrical Couette flow, revealing that weak fluid-wall interactions and low density lead to velocity inversion due to slip and layering effects.

Contribution

It demonstrates the conditions under which velocity inversion occurs in nanoscale flow, linking slip behavior and fluid layering to flow dynamics.

Findings

Velocity inversion occurs with weak fluid-wall interactions.

Low fluid density promotes velocity inversion.

Slip and layering effects are key to the phenomenon.

Abstract

The nanoscale cylindrical Couette flow is investigated by means of molecular dynamics simulations, in the case where the inner cylinder is rotating whereas the outer cylinder is at rest. We find that the tangential velocity of the low is inverted when the fluid-wall interaction near the outer cylinder is weak and the fluid density is low. The unusual velocity inversion behavior is shown to be strongly related to the degree of the slip between the fluid and the outer cylinder, which is determined by the presence or absence of the layering of the fluid near the outer wall.