Anatomy of air entrapment in drop impact on a solid surface

Wu, Zhenlong; Cao, Yihua; Yao, Yufeng

Abstract

When a drop impacts on a solid surface, a thin air film is entrapped first and later evolves into a spherical air bubble at the center inside the drop. The problem involves several complex physical processes, including two-phase fluid flow interactions, moving and deforming interfaces in space and time. In this paper, we dissect the whole air entrapment and evolution process from drop release at a certain height above the substrate to finally a spherical air bubble formation by direct numerical simulation. A detailed quantitative analysis of the various dynamic phenomena occurring at different stages is performed. The complex physical phenomena revealed by current high-fidelity numerical simulations are validated qualitatively against theoretical estimations and previous experimental observations, followed by quantitative comparisons with the theories and available experiments for the dimple, kink and air film. Finally, a new cognition of vortex ring evolution is proposed to explore further insights into the underlying physical mechanisms associated with the evolution of the entrapped air film in liquid-solid impact.

• Journal Article Type: Article
• Acceptance Date: Jun 10, 2021
• Online Publication Date: Jun 15, 2021
• Publication Date: 2021-09
• Deposit Date: Nov 18, 2021
• Publicly Available Date: Jun 16, 2022
• Journal: International Journal of Multiphase Flow
• Print ISSN: 0301-9322
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 142
• Article Number: 103724
• DOI: https://doi.org/10.1016/j.ijmultiphaseflow.2021.103724
• Keywords: Fluid Flow and Transfer Processes; General Physics and Astronomy; Mechanical Engineering
• Public URL: https://uwe-repository.worktribe.com/output/8155236
• Additional Information: This article is maintained by: Elsevier; Article Title: Anatomy of air entrapment in drop impact on a solid surface; Journal Title: International Journal of Multiphase Flow; CrossRef DOI link to publisher maintained version: https://doi.org/10.1016/j.ijmultiphaseflow.2021.103724; Content Type: article; Copyright: © 2021 Elsevier Ltd. All rights reserved.