Research interests

I have a strong interest in multiphase physics, instabilities and dynamical systems.

My PhD research focused on the interactions between a turbulent flow and a bubble, in the context of ocean-atmosphere gas transfers. In this framework, I studied both fragmentation processes and deformations dynamics by performing simulations and then developing reduced order models based on data.

In post-doc at EPFL, I investigate both the linear stability and non linear dynamics of bubbles in model flow geometries. This includes very long Bretherton bubbles, bubbles in uni-axial or bi-axial straining flows, and filament fragmentation. The effect of time variations, potentially stochastic, of the surrounding flow, is also investigated.

Deformations in a model flow

The main flow geometry into which bubbles deform and break in turbulence is an extensional flow. We, then, study bubble deformations and breakage in a uniaxial extensional flow. We show that the full deformation dynamics and breakage can be reproduced by a one-dimensional non-linear oscillator.

Code Uniaxial Uniaxial

Capillary fragmentation in turbulence

Bubbles drive gas transfers at the interface between the atmosphere and the oceans. Small bubbles, smaller than the critical size for bubble stability, are the main contributors. Indeed, they represent the largest surface of exchange. We show that these bubbles are created by the fragmentation of very large bubbles, through filament breaking.

Turbulent bubble Capillary breakage Experiments Sub-Hinze production

Stochastic deformations in turbulence

Turbulent fluctuations randomly deform bubbles. In particular, presssure fluctuations larger than the surface energy of bubbles can induce breakup. For large bubbles, we link short-time deformations as well as bubble lifetime to the turbulent flow statistics. For bubbles smaller than the critical size for bubble stability, we develop a stochastic model that reproduces both the deformation dynamics and the probability to break.

Turbulent bubble Short times Break-up rate Stochastic deformations

Stretched air filaments

Rayleigh-Plateau instability can be modified in several manners. One of them is stretching. We observe that stretching decreases bubble size.