Title : Transport and mixing in effective compressible flows
Contact : Nathanael Machicoane
Abstract : Diffusiophoresis is a mechanism by which colloidal particles suspended in water start to move under the action of a scalar gradient (salt gradient for instance). When such colloids and salt are transported by a flow, the particles do not follow the fluid velocity but have a small drift which proved experimentally to strongly modify the mixing time of colloids concentration in chaotic flows. After reviewing the basic mechanism of diffusiophoresis we will focus on a series of experiments and numerical simulations of laminar mixing which explains how a such small drift, which causes the colloids flow field to become compressible, can dramatically change the way they are dispersed and mixed.