Stéphane Perrard
Junior Resarcher, Ecole Normale Supérieure Paris

Bubble break up in turbulent flows

The transfert of CO2 from the atmosphere to the ocean is estimated to originate at 40% from wave breaking in open seas. Indeed, when a wave breaks, it traps large volumes of air that will fragment and generate submillimetric bubbles. These small bubbles rise slower to the surface and dissolve faster into the ocean. The physical processes at play in bubble fragmentation by turbulent flows have henceforth been studied for more than a century, but the distribution of bubble size, and in particular of the smallest one is still not understood. After a general introduction on bubble fragmentations processed by turbulent flows, I will present our experimental and numerical results on bubble fragmentation, and in particular on the smaller ones. Our approach combines statistical description of turbulent flows with interfacial dynamics, in order to obtain quantitative results on bubble deformation prior to break up, and to deduce expected size distributions in some limit cases.