Formation of soap bubbles by gas jet

TL;DR

This paper investigates the formation of soap bubbles by gas jets, revealing that bubble formation occurs in two velocity ranges corresponding to laminar and turbulent flows, and highlighting the role of aerodynamics in the process.

Contribution

It challenges previous models by showing bubble formation at two velocity ranges and emphasizes the importance of gas jet aerodynamics in bubble formation.

Findings

Bubbles form at two distinct velocity ranges, laminar and turbulent.

The threshold velocity for bubble formation depends on the flow regime.

Aerodynamics significantly influence the bubble formation process.

Abstract

Soap bubbles can be easily generated by varies methods, while their formation process is complicated and still worth study. A model about the bubble formation process was proposed in Phys. Rev. Lett. 116, 077801 recently, and it was reported that the bubbles were formed when the gas blowing velocity was above one threshold. However, after repeating these experiments, we found the bubbles could be generated in two velocities ranges which corresponded to laminar and turbulent gas jet respectively, and the predicted threshold was only effective for turbulent gas flow. The study revealed that the bubble formation was mainly influenced by the aerodynamics of the gas jet blowing to the film, and these results will help to further understand the formation mechanism of the soap bubble as well as the interaction between gas jet and thin liquid film.