The controlled formation of gas bubbles from an orifice is of interest from both a practical perspective, with numerous applications in chemical engineering, as well as a fundamental one, as the pinch-off process is a 'singular flow'. This phenomenon is shown in the YouTube video below.
Video of a gas bubble forming from a needle, from the Supplementary Material in [Thoroddsen et al, 2008].
The approach we have developed, based on a computational platform, allows us to capture global characteristics of the flow, such as the volume of the formed bubble and the time taken, and their dependencies on material parameters such as substrate wettability (see video below).
Growth and detachment of a bubble form a solid surface which is wettable (left) and non-wettable (right). The height of the final bubble on the right is ~1cm
Pinned to a Submerged Orifice
In a recent article [Simmons et al, 2015] our approach is used to map the parameter space relevant for the pinch-off of bubbles from small submerged orifices in which the contact line remains pinned throughout the process. This has allowed us to examine various scaling-laws proposed for the bubble formation process.
Moving Contact Line
Work currently in progress will consider the influence of contact line dynamics on such processes (as shown in the video above).
Talks
Our research in this area was presented at the 2013 BAMC in Leeds by Mr Jonathan Simmons and the presentation can be found here [Simmons et al, 13].
