On the coupling instability of a gas jet impinging on a liquid film

TL;DR

This study uses advanced numerical simulations to analyze the instability of a gas jet impacting a liquid film, revealing similarities across different wiping conditions and offering new insights for industrial applications.

Contribution

It introduces a novel combination of VOF, LES, and emPOD techniques to analyze high Kapitza number liquid films, expanding understanding of jet-wiping dynamics.

Findings

Gas-liquid interaction dynamics are similar across different Kapitza numbers.

Unprecedented resolution captures detailed flow features.

Results suggest scalable principles for industrial jet-wiping processes.

Abstract

We investigate the dynamics of a gas jet impinging on a thin liquid film. This configuration is relevant to the jet-wiping process and is unstable. In particular, we complement previous works that focused on the wiping of liquids with low Kapitza numbers (highly viscous liquids) by numerically analyzing the wiping of liquids with much higher Kapitza numbers, more relevant to industrial processes. The simulations are carried out by combining Volume of Fluid (VOF) and Large Eddy Simulation (LES), and the dynamics of the gas-liquid interaction is analyzed using extended multiscale Proper Orthogonal Decomposition (emPOD). The resolution and flow details captured by the simulations are unprecedented. The results show that, despite the vastly different wiping conditions, the dynamics of the gas-liquid interaction is remarkably similar. This opens new avenues to the study and the scaling of the jet-wiping process.