Velocity slip on curved surfaces

TL;DR

This study demonstrates that the slip length, a measure of velocity slip at boundaries, is a material property transferable across flat, curved, and rotating surfaces when atomic interactions are consistent.

Contribution

The paper extends the Navier boundary condition to curved surfaces and confirms through simulations that slip length remains consistent across various boundary geometries.

Findings

Slip length is consistent across flat and curved surfaces with same atomic interactions.

Navier boundary condition applies to curved and rotating boundaries.

Slip length can be considered a material property, transferable between flow configurations.

Abstract

The Navier boundary condition for velocity slip on flat surfaces, when expressed in tensor form, is readily extended to surfaces of any shape. We test this assertion using molecular dynamics simulations of flow in channels with flat and curved walls and for rotating cylinders and spheres, all for a wide range of solid-liquid interaction strengths. We find that the slip length as conventionally measured at a flat wall in Couette flow is the same as that for all other cases with curved and rotating boundaries, provided the atomic interactions are the same and boundary shape is properly taken into account. These results support the idea that the slip length is a material property, transferable between different flow configurations.