Description du sujet de thèse

Describing exchanges between oceans and atmosphere requires an understanding of change-of-state phenomena such as the evaporation of seawater droplets into the atmosphere and the dissolution of air bubbles in the ocean. It is also crucial to better understand hydrodynamic phenomena such as the entrainment of air into the ocean via wave breaking, or the dispersion of aerosols into the atmosphere when surface bubbles burst. All these phenomena take place at different scales and are affected by physical chemistry due to the presence of biosurfactants, microorganisms and salt in the oceans.

The proposed topic is to examine the influence of physicochemistry on air entrainment and aerosol creation. With regard to air entrainment, we have developed a model experiment in which a jet of liquid impacts the same liquid. During this impact, an air cavity is created which hollows out the interface, and a wave propagates along this cavity, generating (or not) bubbles. An existing experiment allows us to visualize and characterize wave propagation along the cavity, as well as the number of bubbles created (Figure 1 - right). The impact of the presence of salt and surfactants on this cavity and its ability to create bubbles will be explored.

A complementary experiment will observe the rupture of surface bubbles under controlled conditions (thickness, geometry, humidity, physicochemical properties, etc.).

Contexte de travail

MMOI Team https://equipes.lps.u-psud.fr/mmoi/

Contraintes et risques

RAS