Slipping Interfacial Hydrodynamics: Wall Slip Can Cause Drastic Changes in Flow Characteristics at Micro/Nanoscales
Hsien-Hung Wei1*
1Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
* presenting author:Hsien-Hung Wei, email:hhwei@mail.ncku.edu.tw
It is commonly believed that wall slip just does nothing but drag reduction without changing flow characteristics. In this talk I will show that this is not the case for interfacial thin film flows at micro/nanoscales. Specifically, when slip effects are strong, a flow can exhibit characteristics quite distinct from those based on the no-slip condition. The effects at work are illustrated by re-visiting a number of classical free-surface problems in coating and dynamic wetting. It is found that the usual no-slip scaling laws can break down when the film thickness is comparable to or thinner than the slip length. Instead, new strong-slip scaling laws will emerge to govern the dynamics of films. These new results are further accompanied by unique stick-to-slip transitions, providing useful means for probing wall slippage.


Keywords: hydrodynamic clip, thin films, coating, dynamic wetting