Séminaire de Mécanique d'Orsay

Le Mardi 21 novembre 2023 à 14h00 - Salle des séminaires FAST-LPTMS (Bât. 530, salle C.120, 1er)

Phoretic and Marangoni Flows: Studying Self-Propelled Water Droplets and Improving the Efficiency of Blue Energy

Charlotte de Blois
ENS Paris et ESPCI

Observations have revealed that pure water droplets in an outer oil-micelle solution spontaneously propel themselves [1]. This motion arises from the nonlinear coupling between a locally emerging flow and the advection-diffusion of micelles filled with water. Four years ago, I conducted a study on these swimming water droplets in complex situations, such as interacting with walls, confined in one dimension (1D), or interacting with other droplets. I will present a part of my research focusing on the swimming behavior of these droplets in close proximity to a wall, as the presence of the wall breaks the natural axisymmetry of the flow field around the droplet [2]. The study of these swimming water droplets is a fundamental step for the understanding of chemically driven phoretic and Marangoni flows at small scales. Surprisingly, it relates to my current project on optimizing blue energy generation, which harnesses energy from salinity gradients [3], which I will briefly discuss. Furthermore, I intend to use the second part of this seminar as an opportunity to introduce a project proposal for CNRS in collaboration with the FAST laboratory. This proposal can serve as a foundation for future discussions. [1] Z. Izri, M. N. van der Linden, S. Michelin, and O. Dauchot, Self-Propulsion of Pure Water Droplets by Spontaneous Marangoni-Stress-Driven Motion, Phys. Rev. Lett. 113, 248302 (2014). [2] C. de Blois, M. Reyssat, S. Michelin, and O. Dauchot, Flow field around a confined active droplet; Phys. Rev. Fluids 4, 054001 (2019). [3] B. E. Logan, and M. Elimelech, Membrane-based processes for sustainable power generation using water, Nature 488, 313-319 (2012).

Accès Salle des séminaires FAST-LPTMS (Bât. 530, salle C.120, 1er)