Type : Semester project
Understanding the fundamentals of bubble and drop fragmentation is key for a large number of industrial and environmental settings ranging from efficient drug delivery to modeling of air-sea interactions.
There are experimental [1] and numerical [2] evidences that gas bubble breaking under stretching (either gravity or strain) can create a filament which subsequently fragments into numerous tiny bubbles.
Figure: Air bubble in a very viscous fluid, breaking under gravity, creating a large number of tiny bubbles. Adapted from [1].
At this point, the role of the inner fluid properties is still unclear.
In this project, we propose to run direct numerical simulations using the free software Basilisk [3], to investigate the effect of the density and viscosity ratios on the fragmentation dynamics.
To do so, we will use a code which has already been developed and run in the bubble case.
We will focus on:
Characterizing the filament shape at the moment of breakup depending on the viscosity and density ratios.
Characterizing the subsequent fragmentation to understand the bubble/drop sizes produced.
[1] S. T. Thoroddsen, T. G. Etoh, K. Takehara; Experiments on bubble pinch-off. Physics of Fluids 1 April 2007; 19 (4): 042101. https://doi.org/10.1063/1.2710269
[2] A. Rivière et al. “Breakup cascade in gas filament.” arXiv preprint arXiv:2508.00872 (2025).
[3] basilisk.fr
Supervisor(s): Aliénor Riviere & François Gallaire